TWI684296B - Stable organic photosensitive devices with exciton-blocking charge carrier filters utilizing high glass transition temperature materials - Google Patents

Abstract

Disclosed herein are stable organic photosensitive devices including at least one exciton-blocking charge carrier filter. The filters comprise a mixture of at least one wide energy gap material having a sufficiently high glass transition temperature, e.g., higher than the temperature or temperature range at which the device typically operates, higher than a highest operating temperature of the device, higher than a threshold temperature value, etc. and at least one electron or hole conducting material. As described herein, the novel filters simultaneously block excitons and conduct the desired charge carrier (electrons or holes).

Description

Stable organic photosensitive device with exciton barrier charge carrier filter using high glass transition temperature material Cross-reference of related applications

This application claims the rights and interests of US Provisional Application No. 62/026,301 filed on July 18, 2014, which is incorporated by reference in its entirety.

Relevant statement of federally funded research

The present invention is contract numbers DE-SC0000957, DE-SC0001013 and DE-EE0005310 issued by the US Department of Energy (USDepartment of Energy), and FA9550-10-1- issued by the Air Force Office of Scientific Research It is supported by the US government under 0339. The government has certain rights in the invention.

Joint Research Agreement

The subject of the present invention is carried out by representing and/or cooperating with one or more of the following parties to reach a joint university-company research agreement: The Regents of the University of Michigan, the University of Southern California (University of Southern California) and NanoFlex Power. The agreement takes effect on the day of the formulation of the subject of the invention and in advance, and is formulated as the result of various activities carried out within the scope of the agreement.

The present invention relates generally to electroactive, optically active, solar and semiconductor devices, and in particular to an exciton-barrier charge carrier filter including at least one wide-gap material that is morphologically stable at the operating temperature of the device Organic photosensitive optoelectronic equipment Set. This article also discloses a method of manufacturing the organic photosensitive optoelectronic device.

Optoelectronic devices rely on the optical and electronic properties of materials to electronically generate or detect electromagnetic radiation or generate electricity from environmental electromagnetic radiation.

Photosensitive optoelectronic devices convert electromagnetic radiation into electricity. Solar cells (also called photovoltaic (PV) devices) are a type of photosensitive optoelectronic devices that are specifically used to generate electricity. PV devices that can generate electricity from light sources other than sunlight can be used to drive power-consuming loads to provide, for example, lighting, heating, or power electronic circuits or devices (such as computers, radios, computers, or remote monitoring or communication equipment) . These power generation applications usually also involve charging batteries or other energy storage devices, so that when direct lighting from the sun or other light sources is not available, they can continue to operate, or balance the power output of the PV device with the requirements of the specific application. As used herein, the term "resistive load" refers to any power-consuming or storage circuit, device, equipment, or system.

Another type of photosensitive optoelectronic device is a photoconductor battery. In this function, the signal detection circuit monitors the resistance of the device to detect changes caused by absorbed light.

Another type of photosensitive optoelectronic device is a photodetector. In operation, the photodetector is used in conjunction with a current detection circuit that measures the current generated when the photodetector is exposed to electromagnetic radiation and may have an applied bias voltage. The detection circuit described herein can provide a bias voltage to the photodetector and measure the electronic response of the photodetector to electromagnetic radiation.

These three types of photosensitive optoelectronic devices can be characterized according to whether there is a rectifying junction as defined below and also according to whether the device is operated with an applied voltage (also referred to as bias or bias voltage). Photoconductor cells do not have rectifying junctions and usually operate with bias. The PV device has at least one rectifying junction and operates without bias. The photodetector has at least one rectifying junction and usually (but not always) operates with bias. Generally, photovoltaic cells supply power to circuits, devices or equipment, but do not provide signals or current to control the detection circuit or output information from the detection circuit. Conversely, the photodetector or photoconductor provides the signal or current that controls the detection circuit, or the information output of the detection circuit, but does not power the circuit, device, or equipment.

Traditionally, photosensitive optoelectronic devices have been constructed from many inorganic semiconductors (eg, crystalline, polycrystalline, and amorphous silicon, gallium arsenide, cadmium telluride, etc.). The term "semiconductor" as used herein means a material that can conduct electricity when a charge carrier is induced by thermal or electromagnetic excitation. The term "light guide" generally refers to the process of absorbing electromagnetic radiation energy and thereby converting it into the excitation energy of charge carriers so that these carriers can conduct (ie, transport) charges in the material. The terms "photoconductor" and "photoconductive material" are used herein to refer to semiconductor materials selected based on their characteristics of absorbing electromagnetic radiation to generate charge carriers.

PV devices can be characterized by their efficiency in converting incident solar energy into useful electrical energy. Devices using crystalline or amorphous silicon dominate commercial applications, and some have reached efficiencies of 23% or greater. However, the manufacture of effective crystal-based devices (especially those with large surface areas) becomes difficult and expensive due to the problems that exist in manufacturing large crystals without significant efficiency degradation defects. On the other hand, high-efficiency amorphous silicon devices still have stability problems. Recent efforts have focused on the use of organic photovoltaic cells to achieve acceptable photovoltaic conversion efficiency at economical production costs.

The PV device can be optimized to produce the largest amount of electric power under standard lighting conditions (ie, standard test conditions, 1000 W/m ² , AM1.5 spectral lighting), where the product of photocurrent times photovoltage is the largest. The power conversion efficiency of such a battery under standard lighting conditions depends on the following three parameters: (1) the current at zero bias, ie, the short-circuit current I _SC in amperes, (2) the open circuit condition The photovoltage, that is, the open circuit voltage V _OC in volts, and (3) the fill factor FF.

The PV device generates a photo-generated current when it is connected to both ends of the load and illuminated by light. When irradiating under an infinite load, the PV device generates its maximum possible voltage V _{open circuit} (or V _OC ). When irradiated with its electrical contacts shorted, the PV device generates its maximum possible current I _{short circuit} (or I _SC ). When the PV device is actually used to generate power, it is connected to a finite resistive load and the power output is given by the product of current and voltage I×V. The maximum total power generated by the PV device does not substantially exceed the product I _SC × V _OC . When the load value is optimized to obtain maximum power extraction, the current and voltage have the values I _max and V _maximum.

One factor is the quality of the PV device fill factor FF, defined as: FF = {I _maximum V _{max.} / {I SC V OC}} (1)

Among them, FF is always less than 1, because in actual use, I _SC and V _OC are never achieved at the same time. However, as FF approaches 1, the device has a smaller series or internal resistance, and thus provides a larger percentage of the product of I _SC and V _OC under optimal conditions. When P _inc is the incident power on the device, the power efficiency η _{P of the} device can be calculated by the following formula: η _P =FF*(I _SC * V _OC )/P _inc

In order to generate an internal electric field that occupies the substantial volume of the semiconductor, a common method is to arrange two layers of material with suitable conductive properties (especially in terms of the distribution of their molecular energy states). The interface between these two materials is called the photovoltaic bonding interface. In traditional semiconductor theory, the material used to form the PV junction is generally expressed as n or p type. In this article, n-type indicates that most carrier types are electrons. It can be regarded as a material with many electrons in a relatively free energy state. The p-type indicates that most carrier types are holes. This material has many holes in a relatively free energy state. The type of background (ie, non-photogenerated) concentration of most carriers mainly depends on the unintentional doping of defects or impurities. The type and concentration of impurities are determined by the value or level of Fermi energy within the energy gap (also called HOMO-LUMO energy gap) between the minimum conduction band energy and the maximum valence band energy. Fermi energy characterizes the statistical occupancy of molecular energy states represented by an energy value with an occupancy probability equal to 1/2. Fermi energy close to the minimum conduction band (LUMO) can indicate that electrons are the main carrier. Fermi energy close to the maximum valence band (HOMO) can indicate that the hole is the main carrier. Therefore, Fermi energy is one of the main characteristic properties of traditional semiconductors and the prototype PV junction is traditionally a p-n interface.

The term "rectification" especially means that the interface has asymmetric conductive properties, that is, the interface preferably supports electron charge transport in one direction. Rectification is usually associated with a built-in electric field that occurs at the junction between suitably selected materials.

One notable characteristic of organic semiconductors is carrier mobility. Charge carrier It can respond to a measure of the ease with which the electric field moves through the conductive material. In the case of organic photosensitive devices, a layer containing a material that is preferentially conducted by electrons due to high electron mobility may be referred to as an electron transport layer (or ETL). A layer containing a material that is preferentially conducted by holes due to high hole mobility may be referred to as a hole transport layer (or HTL). In some cases, the acceptor material may be ETL and the donor material may be HTL.

Conventional inorganic semiconductor PV cells can use a p-n junction to establish an internal electric field. However, it is now known that in addition to establishing p-n junctions, energy level shifts of heterojunctions also play an important role.

Xianxin's energy level shift at the organic donor-acceptor (DA) heterojunction is important for the operation of organic PV devices due to the basic characteristics of the photovoltaic power generation process in organic materials. When organic materials are photoexcited, local Frenkel or charge transfer excitons are generated. For electrical detection or current generation, the bound excitons must be dissociated into their constituent electrons and holes. This process can be initiated by a built-in electric field, but the efficiency of this electric field (F~10 ⁶ V/cm) usually present in organic devices is extremely low. The most efficient exciton dissociation in organic materials occurs at the DA interface. At this interface, the donor material with low ionization potential forms a heterojunction with the acceptor material with high electron affinity. Depending on the matching of the energy levels of the donor and acceptor materials, the dissociation of excitons at the interface will become energetically favorable, resulting in free electron polarons in the acceptor material and free holes in the donor material Polaron.

Carrier generation requires exciton generation, diffusion, and ionization or aggregation. There is an efficiency η associated with each of these processes. Subscripts can be used as follows: P refers to power efficiency, EXT refers to external quantum efficiency, A refers to photon absorption excitons, ED refers to diffusion, CC refers to aggregation, and INT refers to internal quantum efficiency. Use this notation: η _P ~η _EXT =η _A * η _ED * η _CC

η _EXT = η _A * η _INT

Excitons' diffusion length (L _D ) is usually much smaller than (L _D ~50Å) optical absorption length (~500Å), which requires the use of thick and therefore resistive batteries with multiple or highly folded interfaces, or the use of low There is a trade-off between thin cells for optical absorption efficiency.

Organic PV cells have many potential advantages when compared to traditional silicon-based devices. Organic PV cells are lightweight, economical in material use, and can be deposited on low-cost substrates such as flexible plastic foils. However, in terms of commercialization, new materials and device design methods must be used to further improve device efficiency.

In organic PV cells, it can be seen that interface phenomena dominate key processes, such as charge separation at the donor/acceptor interface and charge extraction at the organic material/electrode interface. In order to improve charge extraction and suppress exciton recombination, a buffer layer is often used between the photoactive region and one or two electrodes.

Wide energy gap materials such as BCP and BPhen have been used as buffers. These materials act by blocking the transmission of excitons due to their wide HOMO-LUMO energy gap, while allowing electron transmission through the defect energy state caused by the deposited cathode. The second function of the wide band gap buffer is to further separate the optical absorption layer from the reflective cathode at the optimal position in the light field. However, these buffers are limited by the extremely thin film (<10 nm) and their high resistance due to the penetration depth of the defect energy state caused during the deposition.

Materials with small HOMO energy, such as Ru(acac), have been used as buffers that transport holes from the cathode to recombine with electrons at the receptor/buffer interface.

A third type of buffer, such as PTCBI and NTCDA, has been developed based on materials with LUMO energy that matches the LUMO energy of the receptor. The LUMO energy level matching allows electrons to be efficiently conducted from the acceptor to the cathode. These materials can also be used to block excitons when their HOMO/LUMO energy gap is large enough. However, these materials hinder device performance if they absorb in the same spectral region as the active layer material. These device architectures must be improved to improve the conversion efficiency of organic PV cells.

The inventor has developed a novel type of buffer, disclosed herein as an exciton-blocking charge carrier filter. The novel buffers include a mixture of at least one wide band gap material and at least one electron or hole conducting material. These filters rely on their Centered to optimize. In other words, the exciton-blocking hole conduction filter is disposed between the photoactive region and the anode to block the excitons and conduct holes to the anode. Conversely, the exciton-blocking electron conduction filter is arranged between the photoactive region and the cathode to block the excitons and conduct electrons to the cathode. For example, in an exciton-barrier electronic filter, electrons are transmitted by electron conducting materials through a mechanism similar to the energy band of impurities. At the same time, the exciton is subject to a combination of an energy barrier caused by a wide band gap material and a statistical barrier caused by a reduction in the number of energy states available for transfer to electronic conductors.

One problem with many buffers, such as BCP or BPhen, is that they are highly resistive and depend on damage-induced transmission states, which limits the actual layer thickness to ~10nm. By mixing a wide bandgap material (such as BCP) with a material with good transmission properties (such as C ₆₀ ), the overall conductivity can be improved by utilizing transmission of similar impurity bands.

The second problem with buffers such as BCP or Bphen is that they can become morphologically unstable at operating temperatures that begin to approach or in some cases exceed their respective glass transition temperature ( _Tg ), which can cause performance degradation over time, Thereby significantly shortening the operating life of the device. Under these conditions, the buffer can crystallize and degrade. The inventors found that by mixing a wide band gap material with an electronic conductor (such as fullerene) or a hole conductor, the buffer layer has increased stability, similar to the morphological "doped pinning". In addition, by using a morphologically stable wide band gap material, that is, a wide band gap material with a sufficiently high glass transition temperature for the exciton-barrier charge carrier filter described herein, it can be significantly extended The operating life of the device.

The exciton-blocking charge carrier filter described herein also acts to prevent the accumulation of charge in the active layer to help reduce exciton-polaron quenching of the exciton, thereby increasing the short circuit current and fill factor of the device. Second role.

In the first aspect of the present invention, the organic photosensitive optoelectronic device includes two electrodes including an anode and a cathode in a stacked relationship; the electrode disposed between the two electrodes to form a donor-acceptor heterojunction includes at least A photoactive region of a donor material and at least one acceptor material, wherein the at least one acceptor material has a lowest unoccupied molecular orbital energy level (LUMO _Acc ) and a highest occupied molecular orbital energy level (HOMO _Acc ), and the At least one donor material has the lowest unoccupied molecular orbital energy level (LUMO _don ) and the highest occupied molecular orbital energy level (HOMO _don ); and the exciton barrier property disposed between the cathode and the at least one acceptor material An electronic filter, wherein the electronic filter includes a mixture comprising at least one cathode side wide band gap material and at least one electron conducting material, and wherein the at least one cathode side wide band gap material has: _-a minimum value equal to or less than the LUMO _Acc unoccupied molecular orbital energy level (LUMO _CS-WG); - is greater than, equal to, or less than 0.3eV in the highest occupied molecular orbital energy level of the HOMO _Acc (HOMO _CS-WG); and - wider than the HOMO _Acc - LUMO _Acc energy gap of HOMO _CS-WG -LUMO _CS-WG bandgap; and wherein the cathode side at least one material having a wide bandgap is equal to or higher than the glass transition temperature of 85 ℃.

In a second aspect, an organic photosensitive optoelectronic device includes two electrodes including an anode and a cathode in a stacked relationship; the electrode disposed between the two electrodes to form a donor-acceptor heterojunction includes at least one donor A photoactive region of the material and at least one acceptor material, wherein the at least one donor material has the lowest unoccupied molecular orbital energy level (LUMO _Don ) and the highest occupied molecular orbital energy level (HOMO _Don ); and is disposed at the anode An exciton-barrier hole filter between the at least one donor material, wherein the hole filter includes a mixture including at least one anode-side wide band gap material and at least one hole conductive material, and the at least one of The anode-side wide bandgap material has:-greater than or equal to the highest occupied molecular orbital energy level of HOMO _Don (HOMO _AS-WG );-less than, equal to, or greater than (farther from the vacuum energy level) LUMO _{Don within 0.3eV} The lowest unoccupied molecular orbital energy level (LUMO _AS-WG ); and-HOMO _AS-WG -LUMO _AS-WG energy gap wider than the HOMO _Don -LUMO _Don energy gap; and at least one of the anode side wide energy gaps The material has a glass transition temperature equal to or higher than 85°C.

As used herein, the term "organic" includes polymeric materials and small molecule organic materials that can be used to manufacture organic photosensitive devices. "Small molecule" refers to any organic material that is not a polymer, and "small molecules" can actually be quite large. In some cases, small molecules may include repeating units. For example, the use of long-chain alkyl groups as substituents does not exclude molecules from the category of "small molecules". Small molecules can also be incorporated into polymers, for example as side groups on the polymer backbone or as part of the backbone.

In the context of the organic materials of the present invention, the terms "donor" and "acceptor" refer to the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy of two contacting but different organic materials The relative position of the order. If the LUMO energy level of a material in contact with another material is further away from the vacuum energy level, the material is the acceptor. Otherwise, it is a donor. In the absence of external bias, it is energetically favorable for electron transfer at the donor-acceptor junction Into the acceptor material, and facilitate the migration of holes into the donor material.

Herein, the term "cathode" is used in the following manner. In a non-stacked PV device connected to a resistive load and without an externally applied voltage or a single unit of a stacked PV device (such as a solar cell) under ambient irradiation, electrons move from the adjacent photoconductive material to the cathode. Similarly, the term "anode" is used herein, therefore, in a solar cell under illumination, holes move from adjacent photoconductive materials to the anode, which is equivalent to electrons moving in the opposite way. It should be noted that the "anode" and "cathode" electrodes may be charge transfer regions or composite regions, such as those used in tandem photovoltaic devices. In a photosensitive optoelectronic device, it may be desirable to enable the maximum amount of ambient electromagnetic radiation from outside the device to be received by the photoconductive active internal region. In other words, electromagnetic radiation must reach the light-conducting layer, where it can be converted into electricity by absorption by the light guide. This usually determines that at least one electrical contact should absorb and reflect incident electromagnetic radiation to a minimum. In some cases, this contact should be transparent or at least translucent. An electrode is said to be "transparent" when it allows at least 50% of the ambient electromagnetic radiation of the relevant wavelength to transmit through it. The electrode is said to be "translucent" when it allows a portion (but less than 50%) of the ambient electromagnetic radiation of the relevant wavelength to be transmitted. The opposite electrode may be a reflective material so that light that has passed through the battery but has not been absorbed is reflected back through the battery.

As used herein, "photoactive region" refers to a region in a device that absorbs electromagnetic radiation to generate excitons. Similarly, a layer is "photoactive" if it absorbs electromagnetic radiation to produce excitons. These excitons can dissociate into electrons and holes in order to generate current.

As used and described herein, "layer" refers to a member or component of a photosensitive device whose main dimension is X-Y (ie, along its length and width). It should be understood that the term layer is not necessarily limited to a single layer or sheet of material. In addition, it should be understood that the surface of some layers (including the interface between these layers and other materials or layers) may be imperfect, where these surfaces represent interpenetrating, entangled, or spiral network structures with other materials or layers. Similarly, it should also be understood that the layer may be discontinuous, so that the continuity of the layer along the X-Y dimension may be disturbed by other layers or materials or otherwise Break.

As used herein, if the first HOMO or LUMO energy level is closer to the vacuum energy level than the second HOMO or LUMO energy level, the first HOMO or LUMO energy level is "less than" the second HOMO or LUMO energy level. Similarly, if the first HOMO or LUMO energy level is farther from the vacuum energy level than the second HOMO or LUMO energy level, the first HOMO or LUMO energy level is "greater than" the second HOMO or LUMO energy level.

As used herein, when the term is used in this article, if its energy matches decile, the energy levels of the two orbits are "equal" to each other. For example, for the purposes of the present invention, a LUMO energy of -3.70 eV will be regarded as "equal to" a LUMO energy of -3.79 eV.

As used herein, LUMO _Acc and HOMO _Acc represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of at least one acceptor material, respectively.

As used herein, LUMO _Don and HOMO _Don represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of at least one donor material, respectively.

As used herein, LUMO _CS-WG and HOMO _CS-WG respectively represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of at least one cathode side wide band gap material.

As used herein, LUMO _AS-WG and HOMO _AS-WG respectively represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of at least one anode-side wide bandgap material.

As used herein, LUMO _EC and HOMO _EC represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of at least one electron conductive material, respectively.

As used herein, LUMO _HC and HOMO _HC respectively represent the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level of at least one hole conducting material.

As used herein, the HOMO-LUMO energy gap is the energy difference between the HOMO and LUMO of a material.

As used herein, the term "between" is intended to include endpoint values in the case of the listed range of glass transition temperature (T _g ) values of wide band gap materials.

The device of the present invention includes at least one exciton barrier charge carrier filter. example For example, FIG. 1 shows a schematic diagram of an organic photosensitive optoelectronic device according to the present invention. The electrode 110 includes an anode or a cathode. In the case where the electrode 110 includes a cathode, the electrode 140 includes an anode. In the case where the electrode 110 includes an anode, the electrode 140 includes a cathode. The photoactive region includes donor/acceptor organic layers 120 and 130 to form a donor-acceptor heterojunction as described herein. The photoactive area may include additional donor and/or acceptor layers to form, for example, a hybrid planar hybrid heterojunction. The organic layer 120 includes at least one donor material or at least one acceptor material. In the case where the layer 120 contains at least one acceptor material, the organic layer 130 contains at least one donor material. In the case where the layer 120 contains at least one donor material, the organic layer 130 contains at least one acceptor material. It should be noted that the donor/acceptor layers in Figure 1 need not be planar. In other words, the present invention covers all types of donor-acceptor heterojunctions known in the related art for organic photovoltaic devices, including those specifically described herein.

In the device A of FIG. 1, when the electrode 110 includes a cathode, the organic layer 120 includes at least one acceptor material, the organic layer 130 includes at least one donor material, and the electrode 140 includes an anode, the layer 115 is exciton-blocking Electronic filter. In the case where the electrode 110 includes an anode, the organic layer 120 includes at least one donor material, the organic layer 130 includes at least one acceptor material, and the electrode 140 includes a cathode, the layer 115 is an exciton-blocking hole filter.

In some embodiments, as in device B, the device includes both exciton-barrier electronic filters and exciton-barrier hole filters. When electrode 110 includes a cathode, organic layer 120 includes at least one acceptor material, organic layer 130 includes at least one donor material, layer 135 is an exciton-blocking hole filter, and electrode 140 includes an anode, layer 115 is Excitonic barrier electronic filter. In the case where the electrode 110 includes an anode, the organic layer 120 includes at least one donor material, the organic layer 130 includes at least one acceptor material, the layer 135 is an exciton-barrier electronic filter, and the electrode 140 includes a cathode, the layer 115 is an excitation Sub-barrier hole filter.

Although not shown in FIG. 1, devices A and B may include other buffer layers or cover layers between the exciton-blocking electron/hole filter and the closest electrode.

The exciton-blocking electronic filter is disposed between the cathode and at least one acceptor material and includes a mixture including at least one cathode side wide energy gap material and at least one electron conductive material. The at least one cathode side wide energy gap material has: _-a minimum unoccupied molecular orbital energy level (LUMO _CS-WG ) less than or equal to LUMO _Acc ;-a maximum occupied molecule greater than, equal to, or less than HOMO _Acc within 0.3 eV Orbital energy level (HOMO _CS-WG ); and-HOMO _CS-WG -LUMO _CS-WG energy gap wider than HOMO _Acc -LUMO _Acc energy gap.

The at least one electronically conductive material having greater than, equal to, or within less than 0.3eV (such as less than 0.2 eV in) the LUMO _Acc lowest unoccupied molecular orbital energy level (LUMO _EC).

In order to extend the operating life of the device by using morphologically stable materials, some embodiments of the present invention use a glass transition temperature that is sufficiently high (eg, higher than the temperature or temperature range in which the device normally operates, higher than the maximum operation of the device Temperature, higher than the threshold temperature value, etc.) wide gap material on the cathode side.

In some embodiments, the HOMO _CS-WG is larger than HOMO _Acc , such as at least 0.2 eV large, at least 0.3 eV large, at least 0.5 eV large, at least 1 eV large, at least 1.5 eV large, or at least 2 eV large, and LUMO _{CS- The WG} system is smaller than LUMO _Acc , such as at least 0.2 eV small, at least 0.3 eV small, at least 0.5 eV small, at least 1 eV small, at least 1.5 eV small, or at least 2 eV small.

In some embodiments, LUMO _EC is equal to LUMO _Acc .

In some embodiments, the LUMO _EC is greater than LUMO _Acc , such as within 0.5 eV greater, within 0.4 eV greater, within 0.3 eV greater, or within 0.2 eV greater.

In some embodiments, LUMO _{EC is} less than or greater than LUMO _{Acc by} no more than 0.1 eV.

In some embodiments, the LUMO _CS-WG system is smaller than LUMO _EC , such as at least 0.2 eV small, at least 0.3 eV small, at least 0.5 eV small, at least 1 eV small, at least 1.5 eV small, or at least 2 eV small.

In some embodiments, the LUMO _CS-WG system is smaller than LUMO _{Acc by} more than 0.2 eV, such as smaller than 0.3 eV, smaller than 0.5 eV, smaller than 1 eV, smaller than 1.5 eV, or smaller than 2 eV.

In some embodiments, the at least one cathode-side wide energy gap material includes a material selected from the group consisting of bath copper spirit (BCP), bath morpholine (BPhen; bathophenanthroline), p-bis(triphenylsilyl)benzene (UGH -2), (4,4'-N,N'-dicarbazole) biphenyl (CBP), N,N'-dicarbazolyl-3,5-benzene (mCP), poly(vinylcarbazole ) (PVK), phenanthrene and phenanthrene substituted with alkyl and/or aryl, benzene derivatives substituted with alkyl and/or aryl, benzophenanthrene and benzophenanthrene substituted with alkyl and/or aryl , Aza-substituted benzophenanthrene, oxadiazole, triazole, aryl-benzimidazole, adamantane and adamantane substituted with alkyl and/or aryl groups, tetraarylmethane and its derivatives, 9,9 -Dialkyl-stilbene and its oligomer, 9,9-diaryl-stilbene and its oligomer, spiro-biphenyl and substituted derivatives, corannulene and its alkyl and/or Aryl substituted derivatives and their derivatives.

62℃)混合物之激子障蔽性電荷載體濾波器之隨時間變化的性能(亦即，標準化響應度、填充因子、Voc及PCE)隨著操作溫度自50℃增加至80℃降級較包含TPBi：C₇₀(TPBi的T_g

122℃)混合物之激子障蔽性電荷載體濾波器之隨著操作溫度自50℃增加至130℃降級更快。換言之，採用TPBi：C₇₀之裝置之性能隨時間降級甚至在更高操作溫度下較採用BPhen之裝置更慢。因此，裝置之效率及操作壽命可藉由例如改由具有更高T_g的陰極側寬能隙材料諸如TPBi代替具有類似T_g值的Bphen及障壁性材料得以改良。 May have a sufficiently high by employing, for example, higher than the temperature or temperature range of the device is generally operated, the apparatus is higher than the maximum operating temperature, higher than the temperature threshold value or the like of the wide-gap side of the cathode material to increase the T _g of the apparatus Operating life. For example, as can be seen in FIGS. 31A to C and 32A to D, including Bphen: C ₆₀ (T _{g of} Bphen

62°C) The time-varying performance of the mixture's exciton-blocking charge carrier filter (ie, standardized responsivity, fill factor, Voc, and PCE) as the operating temperature increases from 50°C to 80°C. The degradation includes TPBi: C ₇₀ (TP _{g Tg}

122°C) The exciton barrier charge carrier filter of the mixture degrades faster as the operating temperature increases from 50°C to 130°C. In other words, the performance of the device using TPBi:C ₇₀ degrades over time even slower than the device using BPhen at even higher operating temperatures. Thus, the efficiency and operating life of the apparatus may be modified by, for example, from the cathode side of the wide-gap material having a higher T _g, such as TPBi instead of having similar T _g values Bphen and barrier material are improved.

In some embodiments, the at least one cathode-side wide bandgap material includes materials that are sufficiently high, for example, higher than the temperature or temperature range at which the device normally operates, higher than the maximum operating temperature of the device, higher than the threshold temperature value, etc. _Tg material. For example, in some embodiments, the at least one cathode side wide energy gap material includes a material selected from the group consisting of: 3,3',5,5'-tetra[(m-pyridyl)-phenyl-3-yl] Benzene (BP4mPy), 2,2',2"-(1,3,5-Petroleum triphenyl (Benzinetriyl))-ginseng (1-phenyl-1-H-benzimidazole) (TPBi), bis( 2-methyl-8-hydroxyquinoline)-4-(phenylbenzyl alcohol) aluminum (BAlq), ginseng (8-hydroxy-quinoline) aluminum (Alq3), ginseng (2,4,6-trimethyl 3-(pyridin-3-yl)phenyl)borane (3TPYMB), 4,40-(1,3-phenylene)bis(2,6-di-p-tolylpyridine-3,5- Dicarbonitrile) (m-MPyCN), 4,40-(1,3-phenylene)bis(2,6-bis(biphenyl-4-yl)pyridine-3,5-dicarbonitrile) (m -PhPyCN), 4,40-(1,3-phenylene)bis(2,6-diphenylpyridine-3,5-dicarbonitrile) (m-PyCN), 6,60-(1,4 -Phenylene)bis(2-phenyl-4-p-tolylnicotinic acid nitrile) (p-PPtNN), 4,40-(1,4-phenylene)bis(2-phenyl-6-p Toluylnicotinonitrile) (p-PPtNT), ginseng (6-fluoro-8-hydroxy-quinoline) aluminum (6FAlq3), 2,6-bis(4-cyanophenyl)-4-phenylpyridine- 3,5-dicarbonitrile (CNPyCN), 4,40-(1,4-phenylene)bis(2,6-di-p-tolylpyridine-3,5-dicarbonitrile) (p-MPyCN), Dibenzimidazolo[2,1-a:1',2-b']anthracene[2,1,9-def:6,5,10-d'e'f']diisoquinoline-10, 21-diketone (PTCBI), 5,10,15-tribenzyl-5H-diindo[3,2-a: 3',2'-c]carbazole (TBDI), 5,10,15 -Triphenyl-5H-diindo[3,2-a: 3',2'-c]carbazole (TPDI), 1,3-bis[3,5-bis(pyridin-3-yl) Phenyl]benzene (BmPyPhB), 1,3,5-tris (m-pyridin-3-ylphenyl)benzene, 1,3,5-Shen(3-pyridyl-3-phenyl)benzene, 3, 3'-[5'-[3-(3-pyridyl)phenyl][1,1': 3',1"-terphenyl]-3,3"-diyl]bispyridine (TmPyPB), 9,9-dimethyl-10-(9-phenyl-9H-carbazol-3-yl)-9,10-dihydroacridine (PCZAC), 3,3-bis(9H-carbazole-9 -Yl) biphenyl (mCBP), 4,40-bis(triphenylsilyl)-biphenyl (BSB) and its derivatives.

In some embodiments, the cathode side wide energy gap material has a glass transition temperature equal to or higher than 85°C, equal to or higher than 95°C, equal to or higher than 105°C, equal to or higher than 115°C, equal to or higher than 125 ℃, 135 ℃ or higher, 145 ℃ or higher, 155 ℃ or higher, 165 ℃ or higher, 175 ℃ or higher, 185 ℃ or higher, Equal to or higher than 195°C, equal to or higher than 200°C, equal to or higher than 225°C or equal to or higher than 250°C.

In some embodiments, the glass transition temperature of the wide energy gap material on the cathode side is between 85 and 200°C, such as between 90 and 195°C, between 95 and 190°C, and between 100 To 185°C, 105 to 180°C, 110 to 175°C, 115 to 170°C, or 120 to 165°C. It should be noted that materials having a glass transition temperature above 200°C, such as between 200 to 300°C, 200 to 275°C, 200 to 250°C, or 200 to 225°C can be used.

The operating temperature of the device can vary and depends on many factors, such as, for example, environmental conditions (eg, temperature, light intensity, etc.) and whether enhancement mechanisms (eg, solar concentrators) are used in conjunction with the device. For example, the ambient temperature may change according to the geographic location of the device, time of year, time of day, and so on. Similarly, light intensity can also depend on geographic location, time of year and time of day, and cloud coverage, angle of incidence, and other factors. Therefore, in some embodiments, the cathode-side wide bandgap material has a sufficiently high temperature, for example, above the temperature or temperature range at which the device normally operates (eg, under normal environmental conditions), and above the device under normal environmental conditions _Tg of the highest operating temperature.

In some embodiments, the solar concentrator may be integrated with or used in conjunction with the device to increase, expand, or otherwise enhance the light directed to the device. The use of concentrators and/or other enhancement mechanisms can increase the operating temperature of the device beyond that experienced by the device under normal environmental conditions. Therefore, to increase the stability and operating life of the device, the cathode side wide bandgap material may have a _Tg that is higher than the maximum operating temperature experienced by the device under enhanced light conditions.

In some embodiments, the at least one acceptor material includes a material selected from the group consisting of phthalocyanines, naphthalene phthalocyanines, dipyrrolene complexes (such as zinc dipyrrolene complexes), BODIPY complexes Compounds, perylene, naphthalene, fullerene and fullerene derivatives (for example, PCBM, ICBA, ICMA, etc.) and polymers (such as polythiophene substituted with carbonyl, polythiophene substituted with cyano, polyphenylene) Ethylene, or polymers containing electron-deficient monomers (such as perylenediamide, benzothiadiazole, or fullerene polymers). Non-limiting mention of those selected from the following: C ₆₀ , C ₇₀ , C ₇₆ , C ₈₂ , C ₈₄ , or derivatives thereof such as phenyl-C ₆₁ -methyl butyrate ([60]PCBM), Phenyl-C ₇₁ -methyl butyrate ([70]PCBM), or thienyl-C ₆₁ -methyl butyrate ([60]ThCBM) and other receptors such as 3,4,9,10-perylenetetracarboxylic acid -Bibenzimidazole (PTCBI), hexafluorophthalocyanine (F ₁₆ CuPc) and its derivatives.

In some embodiments, the at least one electron conducting material includes a material selected from the group consisting of phthalocyanine, naphthalene phthalocyanine, dipyrrolene complex (such as zinc dipyrrolene complex) and BODIPY complex Compounds, perylene, naphthalene, fullerene and fullerene derivatives (for example, PCBM, ICBA, ICMA, etc.) and polymers (such as polythiophene substituted with carbonyl, polythiophene substituted with cyano, polyphenylene) Ethylene, or polymers containing electron-deficient monomers (such as perylenediamide, benzothiadiazole, or fullerene polymers). Non-limiting mention of those selected from the following: C ₆₀ , C ₇₀ , C ₇₆ , C ₈₂ , C ₈₄ , or derivatives thereof such as phenyl-C ₆₁ -methyl butyrate ([60]PCBM), Phenyl-C ₇₁ -methyl butyrate ([70]PCBM), or thienyl-C ₆₁ -methyl butyrate ([60]ThCBM) and other receptors such as 3,4,9,10-perylenetetracarboxylic acid -Bibenzimidazole (PTCBI), hexafluorophthalocyanine (F ₁₆ CuPc) and its derivatives.

In some embodiments, the at least one acceptor material includes a material selected from fullerenes and functionalized fullerene derivatives. In some embodiments, the at least one electron conducting material includes a material selected from fullerenes and functionalized fullerene derivatives.

Particular attention is paid to the use of fullerene as the at least one electron conducting material. C ₆₀ (for example) has an absorption spectrum dominated by two features in solution that have an electron transition due to the allowable generation of the Frenkel-type (ie, single molecule) excited state at 260 nm and 340 nm wavelengths The peak at, while the absorption at longer wavelengths is due to symmetric prohibition transitions. When transitioning from a solution to a solid state, C ₆₀ (for example) undergoes a significant increase in absorption between λ=400 and 550 nm due to the occurrence of electrons excited from the HOMO of a fullerene to its closest neighbor The intermolecular charge transfer (CT) state of the LUMO. When C _{60 is} mixed with a cathode side wide bandgap material such as BCP, the CT state absorption decays more rapidly than the CT state absorption of the Frenkel type characteristic. Therefore, fullerene mixed with a wide bandgap material on the cathode side can be used as a good electron conductive material with reduced absorption rate (even when diluted in materials such as 70% C ₆₀ and 30% wide bandgap), so as not to be rich The exciton generated in the leene electron conductive material will not improve the efficiency of the device in other cases.

In some embodiments, the at least one electron conductive material includes a material selected from C ₆₀ and C ₇₀ .

In some embodiments, the at least one acceptor material and the at least one electron conducting material include the same material. In certain embodiments, the same material is fullerene or a functionalized fullerene derivative. In some embodiments, the same material is C ₆₀ or C ₇₀ . In some embodiments, the at least one acceptor material and the at least one electron conducting material include different materials.

In some embodiments, the at least one acceptor material and the at least one electron conducting material are selected from different fullerenes and functionalized fullerene derivatives.

In some embodiments, the mixture comprises a ratio ranging from about 10:1 to 1:10 (by volume) (such as about 8:1 to 1:8 (by volume), about 6:1 to 1:6 ( (By volume), about 4:1 to 1:4 (by volume), or about 2:1 to 1:2 (by volume)) at least one cathode side wide band gap material and at least one electron conducting material. In some embodiments, the ratio is about 1:1. It should be understood that the indicated ratios include integer and non-integer values.

In some embodiments, the donor-acceptor heterojunction is selected from mixed heterojunctions, bulk heterojunctions, planar heterojunctions, and hybrid planar hybrid heterojunctions. In some embodiments, the donor-acceptor heterojunction is a hybrid planar hybrid heterojunction (PM-HJ). For example, in the PM-HJ structure, there are two main loss mechanisms that lead to low FF. One is the bimolecular recombination of free charge carriers in the vast donor-acceptor doped region of PM-HJ structure, the rate of which is k _BM =γ. n. p is given. Here, γ is the Langevin recombination constant, and n(p) is the density of free electrons (holes). The second significant loss is due to the exciton-polaron quenching in the pure acceptor layer. Electron-polaron accumulation has been observed at the interface of the pure acceptor/barrier layer that leads to quenching and therefore reduced internal quantum efficiency (IQE). It should be noted that the exciton-polaron quenching follows a similar relationship with bimolecular recombination, because the concentration of both excitons and polarons is proportional to the intensity. The two mechanisms will cause the loss of photocurrent under forward bias, which increases the slope of the current density-voltage (JV) characteristic in the fourth quadrant, and ultimately reduces the FF and PCE.

The exciton-blocking electronic filter arranged between the photoactive area and the cathode can improve the efficiency of the double-layer OPV battery. The electron conducting material efficiently conducts electron-polaron while the wide band gap material blocks the exciton. Exciton-polaron quenching can be significantly reduced in double-layer batteries using electronic filters due to their ability to spatially separate excitons and polarons at the barrier interface. This in turn can lead to a significant increase in J _SC , while V _OC and FF remain unchanged. PM-HJ batteries also have the problem of bimolecular recombination in the mixed photoactive layer. However, the filter (hybrid layer) of the present invention results in a reduced interface field with the active layer due to its increased conductivity compared to the purely conventional barrier buffer layer. The resulting increase in the field across the photosensitive region leads to faster charge extraction. This in turn leads to a reduction in bimolecular recombination in the battery.

In some embodiments, the device further includes at least one additional buffer layer or cover layer disposed between the exciton-barrier electronic filter and the cathode. In some embodiments, the at least one covering layer having a greater than, equal to, or less than 0.3 eV in the (such as less than in the 0.2eV) LUMO _EC of the LUMO energy level in the conduction electrons to the cathode. In some embodiments, the LUMO energy level of the capping layer is greater than 0.5 eV, such as greater than 0.4 eV, greater than 0.3 eV, or greater than LUMO _EC in 0.2 eV. In some embodiments, the capping layer has a LUMO energy level that is less than or greater than 0.1 eV than LUMO _EC . In some embodiments, the at least one cover layer is selected from fullerenes and functionalized fullerene derivatives. In some embodiments, the at least one cover layer comprises PTCBI.

In some embodiments, the capping layer includes a material having a LUMO level that is not conducive to conduction of electrons to the cathode. In such embodiments, the cover layer may be thin enough to transport electrons through the damage-induced state. In some embodiments, the at least one cover layer includes a material selected from BCP, BPhen, UGH-2, and CBP.

In some embodiments, the at least one cover layer and the at least one electron conductive material include the same material. In some embodiments, the at least one cover layer, the at least one electron conductive material, and the at least one acceptor material include the same material.

In some embodiments, the at least one cover layer and the at least one cathode side wide energy gap material include the same material.

The exciton-blocking hole filter is disposed between the anode and at least one donor material and includes a mixture including at least one anode-side wide energy gap material and at least one electron conductive material. The at least one anode side wide band gap material has:-greater than or equal to the highest occupied molecular orbital energy level of HOMO _Don (HOMO _AS-WG );-less than, equal to, or greater than the lowest unoccupied molecule of LUMO _Don within 0.3eV Orbital Energy Level (LUMO _AS-WG ); and-HOMO _AS-WG -LUMO _AS-WG energy gap wider than HOMO _Don -LUMO _Don energy gap.

The at least one electrically conductive material having a hole smaller than (closer to vacuum level), is equal to, or greater than 0.2eV in (farther from the vacuum level) the highest occupied molecular orbital energy level of HOMO _Don (HOMO _HC).

In order to extend the operating life of the device by using morphologically stable materials, some embodiments of the present invention use a sufficiently high, for example, higher than the temperature or temperature range where the device normally operates, higher than the maximum operating temperature of the device, high A wide band gap material on the anode side at the glass transition temperature such as the threshold temperature value.

In some embodiments, the HOMO _AS-WG is larger than HOMO _Don , such as at least 0.2 eV large, at least 0.3 eV large, at least 0.5 eV large, at least 1 eV large, at least 1.5 eV large, or at least 2 eV large, and LUMO _AS-WG It is smaller than LUMO _Don , such as at least 0.2 eV small, at least 0.3 eV small, at least 0.5 eV small, at least 1 eV small, at least 1.5 eV small, or at least 2 eV small.

In some embodiments, HOMO _HC is equal to HOMO _Don .

In some embodiments, the HOMO _HC is less than HOMO _Don , such as less than 0.5 eV, less than 0.4 eV, less than 0.3 eV, or less than 0.2 eV.

In some embodiments, HOMO _{HC is} less than or greater than HOMO _{Don by} no more than 0.1 eV.

In some embodiments, the HOMO _AS-WG is greater than HOMO _HC , such as at least 0.2 eV large, at least 0.3 eV large, at least 0.5 eV large, at least 1 eV large, at least 1.5 eV large, or at least 2 eV large.

In some embodiments, the HOMO _AS-WG is greater than 0.2 eV larger than HOMO _Don , such as greater than 0.3 eV, greater than 0.5 eV, greater than 1 eV, greater than 1.5 eV, or greater than 2 eV.

In some embodiments, the at least one anode-side wide energy gap material includes a material selected from the group consisting of: N,N'-diphenyl-N,N'-bis(1-naphthyl)-1-1' Tetraaryl of benzene-4,4'diamine (NPD) and N,N'-bis-(3-methylphenyl)-N,N'-bis-(phenyl)-benzidine (TPD)- Benzidine, triarylamine, 5,10-disubstituted anthracene, oligothiophene, 9,9-dialkyl stilbene and its oligomer, 9,9-diaryl stilbene and its oligomer, oligophenyl , Spiro-biphenyl and its substituted derivatives and their derivatives.

May have a sufficiently high by employing, for example, higher than the temperature or temperature range of the device is generally operated, the apparatus is higher than the maximum operating temperature, higher than the temperature threshold value or the like of the anode side of the wide-gap material to increase the T _g of the apparatus Operating life. For example, in some embodiments, the at least one wide anode-side energy gap includes a material selected from the group consisting of: 3,3',5,5'-tetra[(m-pyridyl)-benzene-3-yl]biphenyl (BP4mPy), 2,2',2"-(1,3,5-petroleum triyl)-ginseng (1-phenyl-1-H-benzimidazole) (TPBi), bis(2-methyl -8-hydroxyquinolinate)-4-(phenylbenzyl alcohol) aluminum (BAlq), ginseng (8-hydroxy-quinoline) aluminum (Alq3), ginseng (2,4,6-trimethyl-3- (Pyridin-3-yl)phenyl)borane (3TPYMB), 4,40-(1,3-phenylene) (2,6-di-p-tolylpyridine-3,5-dicarbonitrile) ( m-MPyCN), 4,40-(1,3-phenylene)bis(2,6-bis(biphenyl-4-yl)pyridine-3,5-dicarbonitrile) (m-PhPyCN), 4 ,40-(1,3-phenylene)bis(2,6-diphenylpyridine-3,5-dicarbonitrile) (m-PyCN), 6,60-(1,4-phenylene) Bis(2-phenyl-4-p-tolylnicotinonitrile) (p-PPtNN), 4,40-(1,4-phenylene)bis(2-phenyl-6-p-tolylnicotine Basic nitrile) (p-PPtNT), ginseng (6-fluoro-8-hydroxy-quinoline) aluminum (6FAlq3), 2,6-bis(4-cyanophenyl)-4-phenylpyridine-3,5 -Dicarbonitrile (CNPyCN), 4,40-(1,4-phenylene)bis(2,6-di-p-tolylpyridine-3,5-dicarbonitrile) (p-MPyCN), bisbenzene Imidazolo[2,1-a:1',2-b']anthracene[2,1,9-def:6,5,10-d'e'f']diisoquinoline-10,21- Diketone (PTCBI), 5,10,15-tribenzyl-5H-diindole[3,2-a: 3',2'-c]carbazole (TBDI), 5,10,15-triphenyl -5H-diindole[3,2-a: 3',2'-c]carbazole (TPDI), 1,3-bis[3,5-bis(pyridin-3-yl)phenyl]benzene (BmPyPhB), 1,3,5-tris(m-pyridin-3-ylphenyl)benzene, 1,3,5-Shen(3-pyridyl-3-phenyl)benzene, 3,3'-[ 5'-[3-(3-pyridyl)phenyl][1,1': 3',1"-biphenyl]-3,3"-diyl]bispyridine (TmPyPB), 9,9- Dimethyl-10-(9-phenyl-9H-carbazol-3-yl)-9,10-dihydroacridine (PCZAC), 3,3-bis(9H-carbazol-9-yl) Benzene (mCBP), 4,40-bis(triphenylsilyl)-biphenyl (BSB) and its derivatives.

In some embodiments, the glass transition temperature of the anode side wide band gap material is equal to or higher than 85°C, equal to or higher than 95°C, equal to or higher than 105°C, equal to or higher than 115°C, equal to or higher than 125 ℃, 135 ℃ or higher, 145 ℃ or higher, 155 ℃ or higher, 165 ℃ or higher, 175 ℃ or higher, 185 ℃ or higher, 185 ℃ or higher, 195 ℃ or higher , Equal to or higher than 200 ℃, equal to or higher than 225 ℃ or equal to or higher than 250 ℃.

In some embodiments, the glass transition temperature of the anode side wide band gap material is between 85 and 200°C, between 90 and 195°C, between 95 and 190°C, and between 100 and 185°C Between, between 105 and 180°C, between 110 and 175°C, between 115 and 170°C, and between 120 and 165°C. It should be noted that materials having a glass transition temperature above 200°C, such as between 200 to 300°C, 200 to 275°C, 200 to 250°C, or 200 to 225°C can be used.

The operating temperature of the device can vary and depends on many factors such as, for example, environmental conditions (eg, temperature, light intensity, etc.) and whether enhancement mechanisms (eg, solar collectors) are used in conjunction with the device. For example, the ambient temperature may change according to the geographic location of the device, time of year, time of day, and so on. Similarly, light intensity can also depend on geographic location, time of year and time of day, and cloud coverage, angle of incidence, and other factors. Therefore, in some embodiments, the anode-side wide bandgap material has a sufficiently high temperature, for example, above the temperature or temperature range at which the device normally operates (eg, under normal environmental conditions), above the device under normal environmental conditions _Tg under the maximum operating temperature.

In some embodiments, the solar concentrator may be integrated with or used in conjunction with the device to increase, expand, or otherwise enhance the light directed to the device. The use of concentrators and/or other enhancement mechanisms can increase the operating temperature of the device beyond what the device experiences under normal environmental conditions. Therefore, to increase the stability and operating life of the device, the anode-side wide energy gap material may have a _Tg that is higher than the maximum operating temperature experienced by the device under enhanced light conditions.

In some embodiments, the at least one donor material includes a material selected from the group consisting of phthalocyanine (such as copper phthalocyanine (CuPc), chloroaluminum phthalocyanine (ClAlPc), tin phthalocyanine (SnPc), zinc phthalocyanine (ZnPc ) And other modified phthalocyanines), subphthalocyanines (such as boron subphthalocyanine (SubPc)), naphthalocyanine, merocyanine dyes, boron-dipyrrolidine (BODIPY) dyes, thiophenes (such as poly(3- (Hexylthiophene) (P3HT)), low-energy band gap polymer, polyacene (such as pentacene and tetracene), diindenoperylene (DIP), squaric acid (SQ) dye, tetraphenyldibenzodiene Indenopyrene (DBP; tetraphenyldibenzoperiflanthene) and its derivatives. Examples of squaric acid donor materials include, but are not limited to, 2,4-bis[4-(N,N-dipropylamino)-2,6-dihydroxyphenyl]squaric acid, 2,4-bis [4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl] squaric acid, 2,4-bis[4-(N,N-diphenylamino)-2, 6-dihydroxyphenyl] squaric acid (DPSQ).

In some embodiments, the at least one hole conductive material includes a material selected from the group consisting of phthalocyanine (such as copper phthalocyanine (CuPc), chloroaluminum phthalocyanine (ClAlPc), tin phthalocyanine (SnPc), zinc phthalocyanine ( ZnPc) and other modified phthalocyanines), subphthalocyanines (such as boron subphthalocyanine (SubPc)), naphthalocyanine, merocyanine dyes, boron-dipyrrolidine (BODIPY) dyes, thiophenes (such as poly(3 -Hexylthiophene) (P3HT)), low-energy band gap polymer, polyacene (such as pentacene and tetracene), diindenoperylene (DIP), squaric acid (SQ) dye, tetraphenyldibenzo Diindenopyrene (DBP) and its derivatives. Examples of squaric acid donor materials include (but are not limited to) 2,4-bis[4-(N,N-dipropylene Aminoamino)-2,6-dihydroxyphenyl] squaric acid, 2,4-bis[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl] squaric acid, 2,4-bis[4-(N,N-diphenylamino)-2,6-dihydroxyphenyl] squaric acid (DPSQ).

In some embodiments, the at least one donor material and the at least one hole conducting material include the same material. In some embodiments, the at least one donor material and the at least one hole conductive material include different materials.

In some embodiments, the mixture comprises a ratio ranging from about 10:1 to 1:10 (by volume) (such as about 8:1 to 1:8 (by volume), about 6:1 to 1:6 ( By volume), about 4:1 to 1:4 (by volume), or about 2:1 to 1:2 (by volume)) of at least one anode-side wide bandgap material and at least one hole conducting material . In some embodiments, the ratio is about 1:1. It should be understood that the indicated ratios include integer and non-integer values.

In some embodiments, the device further includes at least one additional buffer layer or cover layer disposed between the exciton-barrier hole filter and the anode.

The organic photosensitive optoelectronic devices disclosed herein can be grown or placed on any substrate that provides the desired structural properties. Therefore, in some embodiments, the device further includes a substrate. For example, the substrate may be flexible or rigid, flat or non-flat. The substrate may be transparent, translucent or opaque. The substrate can be reflective. Plastic, glass, metal and quartz are examples of rigid substrate materials. Plastic and metal foils and thin glass are examples of flexible substrate materials. The material and thickness of the substrate can be selected to obtain the desired structure and optical properties.

The organic photosensitive optoelectronic device of the present invention can be used as, for example, a PV device such as a solar cell, a photodetector, or a photoconductor.

When the organic photosensitive optoelectronic device described herein is used as a PV device, for example, the material and thickness of the light-conducting organic layer can be selected to optimize the external quantum efficiency of the device. For example, a suitable thickness can be selected to achieve the desired optical pitch in the device and/or to reduce the resistance in the device. When the organic photosensitive optoelectronic device described herein is used as a photodetector or photoconductor, for example, the material and thickness of the light-conducting organic layer can be selected Maximize the sensitivity of the device to the desired spectral region.

In addition, the device may further include at least one smoothing layer. The smoothing layer may, for example, be located between the photoactive layer and either or both electrodes. A film containing 3,4-polyethylenedioxythiophene: polystyrene sulfonate (PEDOT: PSS) is an example of a smoothing layer.

The organic photosensitive optoelectronic device of the present invention can exist as a tandem device including two or more sub-cells. A sub-battery as used herein means a component of a device that includes at least one donor-acceptor heterojunction. When a sub-cell is used individually as a photosensitive optoelectronic device, it usually includes a complete set of electrodes. Tandem devices can include charge transfer materials, electrodes or charge composites or tunnel junctions between tandem donor-acceptor heterojunctions. In some tandem configurations, adjacent sub-cells may utilize a common (ie, shared) electrode, charge transfer region, or charge recombination region. In other cases, adjacent sub-cells do not share a common electrode or charge transfer area. The sub-cells can be electrically connected in parallel or in series.

In some embodiments, the charge transfer layer or the charge recombination layer may be selected from Al, Ag, Au, MoO ₃ , Li, LiF, Sn, Ti, WO ₃ , indium tin oxide (ITO), tin oxide (TO), oxide Gallium indium tin (GITO), zinc oxide (ZO) or zinc indium tin oxide (ZITO). In another embodiment, the charge transfer layer or the charge recombination layer may include metal nanoclusters, nanoparticles, or nanorods.

According to another embodiment, the device of the present invention may include an exciton-barrier charge carrier filter configured between the first sub-cell and the second sub-cell of the device including two or more sub-cells as described herein. For example, FIG. 29 shows a schematic diagram of an organic tandem photosensitive optoelectronic device according to the present invention. The electrode 110 includes an anode or a cathode. In the case where the electrode 110 includes a cathode, the electrode 140 includes an anode. In the case where the electrode 110 includes an anode, the electrode 140 includes a cathode. These tandem devices include two photoactive regions 150 and 160. Each of these regions may include donor and acceptor organic materials to form a donor-acceptor heterojunction as described herein.

In device A of FIG. 29, layer 115 may be an exciton-barrier electronic filter as described herein. In some embodiments, layer 115 may be an exciton-barrier hole filter as described herein. The layer 115 is disposed between the photoactive regions 150 and 160 of the sub-cell. In still other embodiments, as depicted in device B of FIG. 29, the series device may include an additional exciton-blocking charge carrier filter. For example, a tandem photosensitive device may include two charge carrier filters arranged between sub-cells. In this configuration, if the exciton barrier charge filter 115 is an exciton barrier hole filter, then the exciton barrier charge filter 135 is an exciton barrier electronic filter, and vice versa. The tandem device may further include an exciton-blocking charge carrier filter disposed between the photoactive region and the electrode, such as disposed between the photoactive region 150 and the electrode 140.

Although not shown in FIG. 29, devices A and B may further include an additional spacer layer disposed between the sub-cells. The spacer layer may include at least one electrode, at least one charge transfer layer, or at least one charge recombination layer. For example, in the device A, the spacer layer may be disposed between the exciton-barrier charge filter 115 and either of the photoactive region 150 or the photoactive region 160, and may be as close as possible to the exciton-barrier charge filter 115 Adjacent. In some embodiments, the spacer layer is a charge recombination layer as known in the related art or otherwise described herein.

As another example, in device B, the spacer layer may be disposed between exciton-barrier charge filter 115 and exciton-barrier charge filter 135, and may be either one of layers 115 and 135 or Two adjacent. In some embodiments, the spacer layer is a charge recombination layer as known in the related art or otherwise described herein.

To illustrate, in the device A of FIG. 29, if the charge recombination layer is disposed between the layer 115 and the photoactive region 150 and when the electrode 110 includes a cathode, the layer 115 may block excitons and conduct holes from the photoactive region 160 Exciton barrier hole filter to the charge recombination layer.

Or, in the same configuration, except when the electrode 110 is an anode, the layer 115 may be a barrier exciton and conduct electrons from the photoactive region 160 to the exciton-barrier electric charge of the charge recombination layer Subfilter.

The series device may also include two or more exciton-barrier charge filters arranged between the sub-cells as depicted in device B of FIG. 29. If the charge recombination layer is disposed between the layers 115 and 135, when the electrode 110 includes a cathode, the layer 135 may be an exciton-barrier hole filter that shields excitons and conducts holes from the photoactive region 160 to the charge recombination layer. The layer 115 may be an exciton-barrier electronic filter that blocks barrier excitons and conducts electrons from the photoactive region 150 to the charge recombination layer.

Alternatively, in the same configuration, except when the electrode 110 is an anode, the layer 135 may be an exciton-barrier electronic filter that is a barrier exciton and conducts electrons from the photoactive region 160 to the charge recombination layer. The layer 115 may be an exciton-barrier hole filter that is a barrier exciton and conducts holes from the photoactive region 150 to the charge recombination layer.

An advantage of the present invention is that the exciton-barrier charge carrier filter may be transparent due to the use of a wide band gap material. By mixing a transparent wide band gap material with an electron or hole conductive material, the electron or hole conductive material can be sufficiently diluted to make the exciton-barrier charge carrier filter transparent at the relevant wavelength. An exciton-blocking charge carrier filter is called "transparent" when it allows at least 50% of incident electromagnetic radiation of the relevant wavelength to pass through it. In some embodiments, the filters allow at least 60%, at least 70%, at least 80%, at least 90%, or about 100% of incident electromagnetic radiation of relevant wavelengths to transmit therethrough. Charge carrier filters are called optical losses when they absorb very little (<1%) electromagnetic radiation of the relevant wavelength.

In various embodiments, these devices may employ one or more buffer layers that are preferably transparent throughout the visible spectrum. For example, the charge collection/transport buffer layer may be disposed between the photoactive region and the corresponding electrode. For example, the charge collection/transport buffer layer can also be disposed between the spacer layer and the photoactive region. In some embodiments, the charge collection/transport layers include materials selected from metal oxides. In some embodiments, the metal oxide is selected from MoO ₃ , V ₂ O ₅ , ZnO, and TiO ₂ .

Layers and materials can be deposited using techniques known in the related art. For example, the layers and materials described herein can be deposited or co-deposited from solution, vapor, or a combination of both. In some embodiments, the organic material or organic layer can be treated by solution (such as by one or more techniques selected from spin coating, spin casting, spray coating, dip coating, doctor blade, inkjet printing, or transfer printing ) To deposit or co-deposit.

In other embodiments, the organic material may be deposited or co-deposited using vacuum evaporation (such as vacuum thermal evaporation, organic vapor deposition, or organic vapor jet printing).

The exciton-barrier charge carrier filter of the present invention including a mixture of materials can be manufactured by changing the deposition conditions. For example, the concentration of each material in the mixture can be controlled by changing the deposition rate of each material.

It should be understood that the embodiments described herein may be used in combination with various structures. Functional organic photovoltaic devices can be obtained by combining the various layers in different ways based on design, performance, and cost factors, or the layers can be omitted altogether. It may also include other layers that are not explicitly stated. Materials other than those explicitly stated may be used. The names given for the various layers in this article are not intended to be strictly restrictive.

Except in the examples or where otherwise indicated, it should be understood that all numerical values used in this specification and in the scope of patent applications that indicate ingredient amounts, reaction conditions, analytical measurements, etc., are modified by the term "about" in all examples. Therefore, unless indicated to the contrary, the numerical parameters stated in the scope of this specification and the accompanying patent applications are approximate values that can vary with the desired characteristics that the present invention attempts to obtain. At least instead of trying to limit the scope of equality applied to the scope of patent applications, the numerical parameters should be interpreted according to the number of significant digits and the usual rounding method.

Although the numerical ranges and parameters stating the broad scope of the present invention are approximate values, unless stated otherwise, the numerical values stated in the specific examples are reported as accurately as possible. However, any numerical value inherently contains a specific error necessarily caused by the standard deviation present in its respective test measurement.

The devices and methods described herein will be further illustrated by the following non-limiting examples that are intended only as examples.

Examples

Example 1

C ₆₀ and Yutongling (BCP) were mixed in different concentrations to form an exciton-blocking electronic filter. BCP is a wide band gap material with higher singlet (3.17eV) and triplet (2.62eV) energy than C ₆₀ (1.86eV singlet, 1.55eV triplet) and LUMO (-1.6eV), making BCP It is an inert dopant and prevents the transfer of energy and electrons from C ₆₀ at the same time. The doped C ₆₀ :BCP film effectively blocks excitons while still conducting electrons. Based on these properties, applying the doped film as a buffer layer/filter results in improved device performance compared to devices with other buffers.

The effect of BCP doping on fullerene absorption was studied by manufacturing C ₆₀ :BCP films with different volume ratios. The absorption spectrum of the pure and doped C ₆₀ film is shown in FIG. 2. When the fraction of C ₆₀ decreases, absorption decreases and approaches BCP absorption. However, the attenuation of the two absorption peaks at 340 nm and 450 nm corresponding to Frenkel and Charge Transfer (CT) excitons exhibits quite different rates as depicted in the inset of FIG. 2. The extinction coefficient of the permitted Frenkel transition at 340 nm has been linearly fitted to the C ₆₀ fraction as predicted by Beer's law, reflecting the single-molecule nature of this transition. Interestingly, the extinction coefficient of intermolecular CT absorption at 450 nm exhibits an exponential decay and is fitted to the equation α = x ^2.7 , where x is the C ₆₀ volume fraction. This means that the formation of CT excitons involves 2 to 3 molecules. C ₆₀ : The absorption spectrum of the BCP film shows that the doping concentration has a significant effect on CT excitons, even at moderate doping levels it will inhibit its formation.

Example 2

The manufacturing device is as follows: clean the coated patterned ITO with soap (the width of the patterned strip is 2mm, thickness = 150±10nm; sheet resistance=20±5Ω cm ^-2) ; the transmittance at 550nm is 84%; Thin Film Devices, Inc.) glass substrate and boiled in tetrachloroethylene, acetone and propanol (5 min each). The ITO substrate was exposed to an ozone atmosphere (UVOCS T10X10/OES) for 10 min immediately before being loaded into the high vacuum chamber. The deposition rate of the pure material layer is as follows: MoO _x (0.02nm/s), NPD (0.1nm/s), C ₆₀ (0.1nm/s), BCP (0.1nm/s) and Al (0.2nm/s) . The deposition rate of the doped film (C ₆₀ : BCP volume content) is as follows: C ₆₀ : BCP (2:1)-co-deposited C ₆₀ (0.08 nm/s): BCP (0.04 nm/s); C ₆₀ : BCP (1:1)-Co-deposited C ₆₀ (0.06nm/s): BCP (0.06nm/s); C ₆₀ : BCP (1: 2)-Co-deposited C ₆₀ (0.04nm/s): BCP (0.08nm /s). After the organics were deposited, a mask with a strip width of 2 mm was placed on the substrate under N ₂ and an Al cathode of 100 nm was deposited. The area of the device is 4mm ² .

In order to observe the definite optical response from C ₆₀ , a wide band gap hole transmission material N,N'-di-[(1-naphthyl)-N,N'-diphenyl]-1,1' was prepared -Biphenyl)-4,4'-diamine (NPD) as a donor, a double-layer device having the structure illustrated in FIG. 3. The pure layer of C ₆₀ at the D/A interface maintains the thermodynamics and kinetics of charge separation, so that all changes observed between devices will be related to the overall doped film, not to interface effects.

The current-voltage (JV) characteristics under simulated AM1.5G illumination with 1 solar light intensity (100 mW/cm ² ) and the external quantum efficiency (EQE) curve of the device are shown in FIG. 3. As the doping concentration of the C ₆₀ :BCP layer increases from 1:0 to 1:2, the short-circuit current (J _sc ) decreases from 3.0±0.1mA/cm ² by 1.7mA/cm ² to 1.3±0.1mA/cm ² as shown in Table 1. This decrease is due to the decrease in the C ₆₀ optical response as reflected in the EQE measurement, while the open circuit (V _OC ) remains approximately unchanged at 0.87±0.01, and the fill factor (FF) varies with the C ₆₀ fraction Decrease and increase from 0.45±0.01 to 0.49±0.01. There is a good correlation between the decrease in the EQE response and the absorption characteristics of the doped C ₆₀ film, where the decrease in the response between 400 nm and 550 nm is more significant than the response at a wavelength shorter than 400 nm It happens quickly. The effect of CT excitons can be observed most clearly by comparing D1 and D2. In these devices, the EQE response at 350 nm remains unchanged, while the EQE response at 450 nm is reduced from 23% by approximately one-third to 15.5%.

It is observed that the photoresponse decreases with the increase of the BCP doping concentration in the mixed layer, which is distinct from Menke et al., J. Nat. Mater. 2012, where the dilution of SubPc with a wide bandgap material UGH2 resulted in a significant increase in photocurrent. Compared. In the case of SubPc, Menke confirmed that the increase in photocurrent is attributable to the exciton diffusion length caused by the fact that there is a concentration range where the Forster radius increases faster than the average molecular separation distance. increase. The increase in diffusion length is due to the increase in photoluminescence efficiency, excited state lifetime and spectral overlap integral and the decrease in the rate of non-radiative attenuation in the doped film. The comparison between these results can be explained by examining the sources of excitons involved in the two systems. In SubPc, single molecule Frost excitons are formed. At dilution, the absorption loss is linear, and the increase in exciton diffusion length is exponential. Conversely, in C ₆₀ , a significant number of multimolecular CT excitons are formed. At dilution, this leads to an exponential decay of CT exciton formation, which exceeds any increase in diffusion length. Due to the fact that the CT absorption features in C ₆₀ are present in areas of high solar exposure, the overall performance of the device is reduced.

Although hybrid devices have lower photocurrents, the V _{OC of} these devices remains unchanged, showing that retaining the D/A interface can achieve its desired effect. The fact that FF did not decrease at the time of C ₆₀ dilution indicates that the hybrid membrane can efficiently transfer electrons. The combination of the unchanged increase in V _oc and FF and the decrease in J _sc results in the power conversion efficiency (η) at dilution decreasing from 1.14% (D1) by more than 50% to 0.56% (D4). However, the increased transparency and efficient charge transport of hybrid films make C ₆₀ :BCP films an attractive candidate for buffer layers.

Example 3

The device shown in FIG. 4 was manufactured according to the manufacturing method disclosed in Example 2. Figure 4 shows the device's J-V curve and external quantum efficiency as a function of wavelength under 1 sunlight AM1.5 G illumination. The illustration shows the device structure. (x=10nm (D7), 20nm (D6), and 30nm (D5)). Table 2 provides performance data for this device.

Example 4

The device shown in FIG. 5 was manufactured according to the manufacturing method disclosed in Example 2. Fig. 5 shows the device's J-V curve and external quantum efficiency as a function of wavelength under one AM1.5G illumination. The illustration shows the device structure. (x=0nm (D8), 20nm (D9) and 40nm (D10)). Table 3 provides performance data for this device.

Example 5

35nm厚及另一層為[40nm-x]厚)之間之包含10nm厚BCP：C₆₀層之OPV。純淨C₆₀及BCP：C₆₀膜之總厚度為50nm。圖6顯示x=5nm至35nm之裝置D20-D23之J-V及EQE特徵，其他性能參數提供於表4中。J_SC隨著BCP：C₆₀層移向D/A界面(亦即，隨著x減小)自 6.2±0.3mA/cm²減小至4.1±0.2mA/cm²。此趨勢於EQE光譜中亦明顯，其中來自C₆₀之響應隨著與D/A界面相鄰的純淨C₆₀層之厚度之減小(表4中的D20至D23)而減低。該等數據顯示BCP：C₆₀防止於與金屬電極相鄰的C₆₀膜中產生之激子擴散至D/A界面，在該D/A界面處可發生解離形成自由電荷。相對地，如由恆定及高FF=0.72±0.01及V_oc=0.94±0.01V推斷得，混合層不阻礙電荷傳輸。與D/A界面相鄰的C₆₀層之厚度自x=5nm增加至35nm使得於1個太陽光、AM 1.5G照明下之功率轉換效率自2.7±0.1%增加至4.1±0.1%。 The OPV device shown in Figure 6 (bottom inset) was produced. The red absorption donor (2,4-bis[4-(N,N-diphenylamino)-2,6-dihydroxyphenyl] squaric acid) (DPSQ) was made sandwiched between two C ₆₀ layers (One layer is x

OPV between 35nm thick and another layer [40nm-x] thick) including 10nm thick BCP: C ₆₀ layer. Pure C ₆₀ and BCP: The total thickness of the C ₆₀ film is 50 nm. Figure 6 shows the JV and EQE characteristics of devices D20-D23 with x=5nm to 35nm. Other performance parameters are provided in Table 4. With the BCP:C ₆₀ layer, the J _SC moves to the D/A interface (that is, as x decreases) from 6.2±0.3 mA/cm ² to 4.1±0.2 mA/cm ² . This trend is also evident in the EQE spectrum, where the response from C ₆₀ decreases as the thickness of the pure C ₆₀ layer adjacent to the D/A interface decreases (D20 to D23 in Table 4). These data show that BCP:C ₆₀ prevents excitons generated in the C ₆₀ film adjacent to the metal electrode from diffusing to the D/A interface where dissociation can occur to form free charges. In contrast, as inferred from constant and high FF=0.72±0.01 and _Voc =0.94±0.01V, the mixed layer does not hinder charge transfer. The thickness of the C ₆₀ layer adjacent to the D/A interface increased from x=5nm to 35nm, which increased the power conversion efficiency under 1 sunlight and AM 1.5G illumination from 2.7±0.1% to 4.1±0.1%.

Example 6

The device shown in FIG. 7 was manufactured according to the manufacturing method disclosed in Example 2. Fig. 7 shows the J-V curve of the device under the illumination of 1 sunlight AM1.5G, in which the inset shows the characteristics of the device, and the external quantum efficiency as a function of wavelength, in which the inset shows the structure of the device. These devices compare the performance of mixed buffer layers and single pure PTCBI buffer layers that are covered with other layers to improve charge accumulation.

Example 7

The device shown in FIG. 8 was manufactured according to the manufacturing method disclosed in Example 2. Fig. 8 shows the external quantum efficiency of different buffer layers for EQE normalization under zero bias under applied bias (+0.5V dashed line, -1V solid line). These data show that the hybrid buffer layer reduces the bias dependence of the device, indicating that the charge accumulation at the active layer/buffer interface is reduced, thus reducing the amount of exciton-polaron quenching.

Example 8

The mechanism of the mixed layer barrier exciton can be considered in a statistical manner, in which the reduction of the energy state density available in the doped layer reduces the exciton transfer rate. There is a significantly reduced amount of energy that can be transferred into the energy state in the mixed layer, thereby effectively blocking the progress of the energy state. The effect of energy state density was simulated by Monte Carlo simulation. The results can be seen in Fig. 9. In this model, excitons are randomly generated in the pure film adjacent to the mixed film. To simulate diffusion, the exciton then moves through random steps to set the number of distances and record its final position. Suppose that these excitons are transferred only by nearest neighbor hopping. At the interface between the doped layer and the pure layer, the probability of jumping between layers is measured by the relative number of effective sites in each layer. The model predicts that for the junction between two materials with equal site density, 50% of the excitons diffuse into the buffer. In the case where the position in the buffer is reduced by 50%, this situation corresponds to the case where the C ₆₀ Frenkel exciton is close to 1:1 C ₆₀ : BCP buffer, and only 20% of the excitons are transferred. When the simulated CT excitons approached 1:1 C ₆₀ :BCP buffer and 80% of the sites were reduced, less than 5% excitons were transferred. Even when only statistical methods are considered, these simulations confirm that the doped buffers shield the excitons quite well.

Example 9

As shown in Figure 10, the normalized extinction spectrum of C ₇₀ covered with different buffer layers as a function of wavelength is plotted on the upper graph. These data show that the exciton energy becomes larger with more mixing, which helps shield the exciton. The bottom graph shows the emission spectrum of C ₇₀ (excitation at 450 nm) covered by quenching (NPD), barrier (BCP) and mixed buffer layers.

Example 10

As shown in FIG. 11, the EQE spectrum of the device covered with different buffer layers (top) and the JV curve (bottom) of the device under 0.8 sunlight AM1.5G illumination show that the composite buffer is included compared to other buffer layers. The resulting performance is improved.

Example 11

The study included the use of C ₆₀ : BCP buffers and compared their performance with the previously developed buffers BCP and PTCBI, and the performance in C ₆₀ : BCP composite buffers covered with BCP or PTCBI. In these devices, the active layer contains DPSQ/C ₆₀ . JV, EQE and device architecture are shown in Figure 12, and related data are shown in Table 5. The V _{oc of the} device is kept constant at 0.95±0.01V, regardless of the buffer. The device covered with 10 nm PTCBI buffer (D13) showed a minimum J _{sc of} 7.1±0.1 mA/cm ² due to parasitic optical absorption from PTCBI. ²⁰ Unlike PTCBI, other buffers with a thickness of 10 nm, BCP (D11) and C ₆₀ : BCP (D12) do not absorb, resulting in J _SC increasing to 7.5±0.1 mA/cm ² and 7.6±0.1 mA/cm ^{2, respectively} . The composite buffer layer with a thickness of 15nm (C ₆₀ : BCP/PTCBI (D14) and C ₆₀ : BCP/BCP (D15)) has an even higher value of 8.1±0.1mA/cm ² and 8.3±0.1mA/cm ^{2 respectively} Jsc. EQE measurement confirmed that the change in photocurrent was due to the change in C ₆₀ response, and the optical modeling using transfer matrix method ⁹ confirmed that the increase in J _SC when the buffer was changed from 10 nm to 15 nm was due to the optical effect. The FF between devices also changed significantly. The devices covered by BCP (D11 and D15) showed a minimum FF of 0.64±0.01 and 0.65±0.01, respectively. The buffer containing only C ₆₀ :BCP(D12) has a slightly better FF of 0.66±0.01. The devices covering PTCBI (D13 and D14) exhibited maximum FF of 0.68±0.01 and 0.71±0.01, respectively. Due to the increase in photocurrent and FF, compared to C ₆₀ : 5.0±0.1% of BCP/BCP, C ₆₀ : 4.8±0.1% of BCP, 4.8±0.0=1% of PTCBI and 4.8±0.1% of BCP , C ₆₀ : The power conversion efficiency of BCP/PTCBI buffer is the largest, which is 5.3±0.1%.

The difference in FF between the buffer layers can be explained by examining the EQE and responsivity (R) under applied bias as a function of the intensity of the illumination. Figure 13 shows the EQE of a device with different buffer layers normalized to its 0V EQE under a -1V bias. The signal from the C60 between 400nm and 550nm is modulated by applying an external bias voltage, while the DPSQ response between 600nm and 825nm remains unchanged. The amount of EQE that can deviate from zero bias is worth knowing the effect of the buffer layer. For the device covered with 10nm BCP buffer (D11), the voltage dependence is the most significant, and for the 10nm _C60 : BCP buffer (D12), the voltage dependence is the smallest.

The device covered by 10nm _C60 : BCP/5nm BCP (D15) experienced less voltage dependence than 10nm BCP (D11). This system is due to two factors. The first factor is that the thinner BCP layer reduces the number of trapped electrons. The second factor is that, as shown above, the C ₆₀ :BCP layer blocks excitons so as not to diffuse to the C ₆₀ :BCP/BCP interface, but still transmits electrons. This prevents excitons from interacting with electrons trapped at the C ₆₀ :BCP/BCP interface.

The 10 nm PTCBI (D13) buffer allows electrons to be transported from C ₆₀ etc. due to its LUMO matching. At the same time, the PTCBI/Ag interface does not form dipoles or energy barriers for charge extraction. 10nm C ₆₀ : BCP/5nm PTCBI (D14) acts in a similar manner, while also preventing excitons from reaching PTCBI.

The exciton quenching caused by polaron-excitons is further confirmed by the responsivity shown in view 13 as a function of illumination intensity. Responsivity is defined as the short circuit current density of the device divided by the incident light area intensity. This parameter allows us to compare the current generation efficiency of the device under different lighting intensities. The BCP (D11 and D15) covered devices exhibited a significantly non-linear response as the illumination increased from 1 W/m ² (0.01 sunlight) to 100 W/m ² (1 sunlight). The nonlinear nature of the attenuation is consistent with the exciton quenching caused by the exciton-polaron, where the increased illumination intensity causes the number of excitons and polarons to increase simultaneously. The other buffers used in D12, D13, and D14 all exhibit small changes in responsivity as a function of illumination intensity, confirming that the exciton quenching caused by exciton-polaron is suppressed.

Example 12

To study the exciton-blocking properties of C ₆₀ : BCP, the red absorption donor (2,4-bis[4-(N,N-diphenylamino)-2,6-dihydroxyphenyl]squaric acid) was used (DPSQ) ^{20, 21} made a device containing a doped C ₆₀ layer sandwiched between two pure C ₆₀ layers (Figure 14). Pure C ₆₀ and C ₆₀ : The total thickness of the BCP film is constant; only the position of the doped film is moved away from the D/A interface toward the Ag electrode.

The JV and EQE characteristics of device D16-19 are shown in Figure 14 and the related data is shown in Table 6. As the thickness of the pure C ₆₀ layer adjacent to the D/A interface decreases from 35 nm to 5 nm (or C ₆₀ : the BCP layer moves toward the D/A interface), the photocurrent of the device is significant from 6.2±0.1 mA/cm ² Underground drops to 4.1±0.1mA/cm ² . This trend can also be observed in the EQE spectrum, where the response from C ₆₀ decreases as the thickness of the pure C ₆₀ layer adjacent to the D/A interface decreases (D16 to D19). These results clearly confirm that C ₆₀ :BCP acts as an exciton blocking layer by effectively shielding excitons generated in the pure C ₆₀ film adjacent to the metal electrode so as not to diffuse to the D/A interface to achieve charge separation. Contrary to its exciton blocking effect, the doped layer exhibits good charge conductivity because the FF of the device is kept constant at about 0.72±0.01. V _OC also maintains constant at 0.94±0.01. Overall, increasing the thickness of the pure C ₆₀ layer adjacent to the D/A interface from 5 nm to 35 nm increases η from 2.7±0.1% to 4.1±0.1%.

Example 13

Fig. 15 shows a graph of the J-V curve under the illumination of 1 sunlight AM1.5G at the top and the external quantum efficiency of the devices with different buffer layers at the bottom as a function of wavelength. These devices confirmed the improved performance due to the inclusion of mixed buffer layers.

Example 14

16 shows a graph of the external quantum efficiency of a device with different buffer layers containing different ratios of C ₆₀ to BCP at the bottom and the JV curve at the top under 1 sunlight AM1.5G illumination. These devices confirmed the best doping ratio of 1:1 (by volume).

Example 15

A device having the following structure was prepared: glass substrate/100 nm ITO/10 nm MoO ₃ /54 nm 1:8 DBP: C ₇₀ /buffer/100 nm Ag. Figure 17 shows the JV (upper left) and EQE of the illumination of a planar hybrid OPV battery with a relatively thick 1:8 volume ratio of DBP and an active layer of pure C ₇₀ layers under 1 sunlight simulated AM1.5G illumination (Upper right) and extraction efficiency parameters (lower). The thickness and volume ratio of BPhen:C _{70 for} each buffer is provided in the table. The best fill factor and efficiency are for devices with mixed buffers and an additional BPhen or PTCBI layer between the mixing area and the contact, confirming that the contact also improves the hybrid or integral heterojunction device.

Example 16

A device having the following structure was prepared: glass substrate/100nm ITO/5nm MoO ₃ /25nm 1:8 DBP: C ₇₀ /buffer/100nm Ag. Figure 18 shows the JV (top left) of a planar hybrid OPV battery with an active layer including a relatively thin 1:8 volume ratio of DBP and pure C ₇₀ layers and various buffers under 0.7 sunlight simulated AM1.5G illumination Picture) and EQE (upper right picture) and extraction efficiency parameters (below). The thickness and volume ratio of BCP:C _{70 for} each buffer is provided in the table. The best fill factor and efficiency are for devices with mixed buffers and an additional BPhen or PTCBI layer between the mixing area and the contact, confirming that the contact also improves the hybrid or integral heterojunction device and can be used in the mixed layer device Excellent fill factor is obtained.

Example 17

A device having the structure shown in Fig. 19 was produced. The device in FIG. 19(a) has the structure ITO/MoO ₃ /DPSQ/C60/C ₆₀ : BPhen(x)/BPhen/Al. The device in FIG. 19(b) has the structure ITO/MoO ₃ /DPSQ/C60/C ₆₀ : BCP(x)/BPhen/Al. The device in FIG. 19(c) has the structure ITO/MoO ₃ /DPSQ/C60/C ₆₀ : UGH2(x)/BPhen/Al. Figure 19 shows the EQE and JV curves diluted with BPhen, CBP and UGH2. An increase was observed in all cases, confirming the reduction of charge accumulation at the C ₆₀ /buffer interface to achieve an increase.

Example 18

The OPV battery was grown by vacuum thermal evaporation (VTE) on a glass substrate pre-coated with indium tin oxide (ITO, sheet resistance: 15Ω/□) at a base pressure of 2×10 ^-7 torr. Prior to deposition, the substrates were cleaned in diluted Tergitol® (NP-10 type), deionized water, acetone, and isopropanol, and then exposed to UV-ozone for 10 min. MoO ₃ was obtained from Acros Organics, C ₆₀ was obtained from Materials and Electrochemical Research Corp., BPhen and DBP were obtained from Luminescence Technology Corp, and C ₇₀ was obtained from SES Research. DBP, C ₆₀ and C _{70 were} purified once by thermal gradient sublimation.

MoO ₃ and based at BPhen layer / s rate of growth 0.1nm, DBP DBP system using C ₇₀ and a deposition rate of 0.02nm / s and of 0.16nm / s of C ₇₀ to achieve co-deposition deposition rate of 1: 8 ratio of. The BPhen:C ₆₀ mixed buffer is grown by co-depositing BPhen and C ₆₀ each at a rate of 0.05 nm/s to establish a 1:1 dopant. A 100 nm thick Ag cathode was then deposited through a shadow mask defining an array of 15 1 mm diameter devices (device area 0.008 cm ² ). After manufacturing, the device was transferred to a glove box filled with ultra-high purity N ₂ to measure JV characteristics and EQE. During the measurement, only the test device is under illumination, while the other devices are maintained in the dark. The solar simulator intensity system is calibrated using NREL-traceable Si reference cells, and the J _SC system corrects for spectral mismatch. EQE is obtained as a function of wavelength (l) using a lock-in amplifier and monochromatic light from a Xe lamp with a chopping frequency of 200 Hz. The errors of J _SC and PCE mainly come from the uncertainty of light intensity and spectral calibration.

A hybrid HJ battery having the following structure was grown by vacuum thermal evaporation (VTE): MoO ₃ (10 nm)/DBP: C ₇₀ (54 nm, 1:8 volume ratio)/buffer/Ag (100 nm). Two different buffer layers were used: 8 nm thick BPhen (control group) and a 10 nm thick 1:1 ratio (by volume) BPhen:C ₆₀ mixed layer covered with a pure 5 nm thick BPhen layer. Figure 20 shows the JV characteristics and EQE spectrum of a mixed HJ device using a control group and a composite buffer. The control group had FF=55±1% under simulated AM 1.5G, 1 sunlight illumination (spectral mismatch factor=1.00±0.01), J _SC =12.5±0.3mA/cm ² , V _OC = 0.91±0.1V and PCE=6.3±0.3%. A battery with a composite electron-filter buffer exhibits improvements in all three performance parameters, achieving FF=63±1%, J _SC =12.8±0.3mA/cm ² , V _OC =0.93±0.1V and PCE=7.5± 0.4%, the latter corresponds to a 19% increase in the control group.

The significant improvement of the FF of the device with composite buffer is shown in FIG. 20(a) (indicated by the shaded area between the two curves), and the energy level diagram in the inset of FIG. 20(b). The above study shows that energy level bending occurs at the fullerene/BCP interface, resulting in electron accumulation and a large potential drop as shown in the left-hand inset. Therefore, the electric field across the active layer decreases as the voltage is redistributed, thereby increasing the charge extraction time, and therefore the retention time of electrons and holes at the donor-acceptor heterogeneous interface where they have a chance to recombine. In the case of a composite buffer, the high conductivity of the 1:1 BPhen:C ₆₀ dopant leads to less electron accumulation, and therefore a smaller potential drop and DBP at the interface (inset on the right, Figure 20(b)) : Higher electric field in the C ₇₀ mixed area. This in turn leads to reduced bimolecular quenching, and therefore to an increase in FF and EQE at wavelengths between 1=400 nm and 550 nm as shown in FIG. 20(b).

Both batteries showed almost the same EQE at l<400nm and λ>550nm (see Figure 20(b)). At λ<400nm, the parasitic absorption in the BPhen:C ₆₀ mixed buffer in the composite buffer battery leads to a decrease in the absorption of the photoactive region, and the internal quantum efficiency (IQE) is increased by the reduced bimolecular recombination. Overall, the EQE of the composite buffer battery is almost equal to the control battery. At λ>550nm, the absorbed optical power peak and the charge distribution peak shift toward the anode. This is because the excitons generated in the DBP:C ₇₀ mixed region dissociate into charges almost immediately. This reduces the number of holes at the DBP:C ₇₀ /BPhen interface (near the cathode side) of electrons deposited in the control battery, while improving hole extraction. The spatial separation of holes and electrons at longer excitation wavelengths reduces the bimolecular recombination in the control cell and also results in nearly equal EQE.

γ．n．p

b．I²，其中γ為郎之萬係數及b為常數。因此，R=J_SC/I=R₀-β．I，其中R₀為不存在雙分子複合下之響應度。就兩種電池而言，針對該分析之線性擬合(虛線，圖21)獲得R₀=12.9 A/W。兩種電池於零光強度下之相同截距顯示兩種OPV電池具有與不存在雙分子複合情況下I→0相同的響應度。然而，對照組之β係四倍大於具有複合緩衝物之電池之複合緩衝物電池之較小的β顯示雙分子複合僅為對照組電池之25%，指示電子及電洞濃度因混合區域中電場之增加而各自平均減低50%。就指定外部偏壓而言與對照組者相比複合緩衝物電池中異質接面兩端之此種較大內部電場導致經改良之電荷提取及因此較高之FF。 The functional relationship between the responsivity (R) and light intensity (I) of two batteries was studied to understand the effect of bimolecular recombination. It was found that the battery of the control group had a monotonous decrease in R with I, from R=12.7±0.4 A/W under I=0.6 sunlight to 11.8±0.3 A/W under I=2.7 sunlight, and the compound buffer For the battery, R only decreases by 0.2 A/W in the same intensity range (see Figure 21). Generally speaking, J _SC =J _G -J _MM -J _BM , where J _G is the photogenerated current density, J _MM is the single-molecule composite current density and J _BM is the bi-molecular composite current density. J _G and J _MM are linearly proportional to I, while J _BM

γ. n. p

b. I ² , where γ is the Langevin coefficient and b is a constant. Therefore, R=J _SC /I=R ₀ -β. I, where R ₀ is the responsivity in the absence of bimolecular recombination. For the two batteries, R ₀ =12.9 A/W was obtained for the linear fit of the analysis (dashed line, Figure 21). The same intercept of the two batteries at zero light intensity shows that the two OPV batteries have the same responsivity as I → 0 in the absence of bimolecular recombination. However, the β of the control group is four times larger than the smaller β of the composite buffer battery of the battery with a composite buffer. The bimolecular recombination is only 25% of the battery of the control group, indicating the concentration of electrons and holes due to the electric field in the mixed region The increase has been reduced by an average of 50%. This larger internal electric field at both ends of the heterojunction in the composite buffer battery compared to the control group for the specified external bias voltage resulted in improved charge extraction and therefore higher FF.

The charge transfer properties of the composite buffer were further studied by 3-D Monte Carlo simulation of the layer programmed with Matlab. The buffer system is modeled as BPhen and C ₆₀ molecules are randomly distributed on the cubic lattice, where the electron transport is attributed to the nearest neighbor hop between C ₆₀ molecules. In this model, the Columbic interaction between charges is ignored, and it is assumed that the lattice sites are isoenergetic except for the energy difference caused by the applied electric field. The transfer probability is calculated according to the Miller-Abrahams theory, and the median extraction time of the charge injected on the side of the buffer layer is obtained from the transfer probability. Then, the mobility of the layer is calculated from the relationship between the extraction time and the electric field. By setting the zero field mobility of the electrons in the pure C ₆₀ layer to 5.1×10 ^-2 cm ² /V. The experimental value of s is standardized. For 1:1 mixed buffer, the model predicts 4.7×10 ^-3 cm ² /V. The effective mobility of s is only an order of magnitude lower than the effective mobility of pure C ₆₀ . In comparison, the pure BPhen film has 1.9×10 ^-5 cm ² /V. The significantly lower electron mobility of s leads to charge accumulation at the buffer interface and promotes quenching.

The model was tested by examining the predictions for different thicknesses of the 1:1 mixed buffer, and the results are shown in Figure 22(a). There is a linear relationship between the extraction time at a specified voltage (corresponding to the film mobility) and the thickness of the mixed layer. Assuming that the charge density is constant (that is, the illumination intensity is constant), this relationship is converted into a linear increase in series resistance. The fitting of the experimental data for the mixed buffer DBP: C ₆₀ OPV is shown in the inset of FIG. 22(a). Next, the pure BPhen layer conducts electrons through the defect energy states caused during metal deposition, resulting in an ultra-linear relationship between thickness and resistance. In contrast, the resistance of the mixed buffer increases linearly with thickness up to 20 nm, showing that the electrons in the mixed buffer are mainly conducted by C ₆₀ in the mixture.

The experimental method was used to study the exciton blocking efficiency of the photoluminescence (PL) excitation spectrum of a 40 nm thick C ₇₀ film covered with 1:1 BPhen:C ₆₀ dopant on quartz. The relative importance of these processes can be determined by comparing the PL intensity of the layer deposited on the surface of the dopant under study with the PL intensity of either the "complete" barrier layer or the quenching layer. Based on this, 8nm thick BPhen or N,N'-diphenyl-N,N'-bis(1-naphthyl)-1-1'-biphenyl-4,4'diamine (NPD) are used respectively The layer serves as a reference, completely exciton masking or quenching layer. The PL intensity of the mixed buffer is almost equal to the measured intensity of the barrier reference (see Figure 22(b)), confirming that the BPhen:C ₆₀ mixed layer can effectively block excitons. Due to the relatively high electron mobility of the BPhen:C ₆₀ mixture, the mixed buffer layer can spatially separate the excitons and polarons that serve as effective filters, resulting in exciton-polaron in the pure fullerene layer Reduced quenching.

Example 19

According to the experiment disclosed in Example 18, an OPV battery with a hybrid planar hybrid heterojunction (PM-HJ) was produced. In OPV batteries, DBP and C _{70 are} used as donors and acceptors, respectively. The OPV battery has a device structure of indium tin oxide (ITO)/MoO ₃ (10 nm)/DBP: C ₇₀ (54 nm, 1:8 volume ratio)/C ₇₀ (9 nm)/buffer/Ag (100 nm). Use three different buffer layers in the DBP: C ₇₀ PM-HJ OPV battery: (1) 8 nm thick bath morpholine (BPhen) (control group); (2) 10 nm thick 1:1 ratio to BPhen: C ₆₀ mix Layer; and (3) the same mixed buffer as (2) covered with a pure 5 nm thick BPhen layer.

FIG. 23 shows external quantum efficiency EQE spectra of current density versus voltage (J-V) characteristics and comparative performance of devices using buffer layer structures (1) to (3), summarized in Table 7.

The battery in the control group has FF=56% and short-circuit current J _SC =13.8±0.4 mA/cm ² , which is equivalent to or slightly better than the above results. ¹ Therefore, the battery of the control group is shown in the simulated AM 1.5G, and the power conversion efficiency under one sunlight illumination PCE=7.1±0.2%. Compared with the control battery, the battery with only BPhen:C ₆₀ (1:1) filter has a similar open circuit voltage (V _OC )=0.91±0.01V, but the increased FF=62±1%. It is due to the reduced quenching of polaron-excitons. ^2,3 However, J _SC =12.8±0.3mA/cm ² , which is slightly reduced, this is due to the result of reduced EQE for λ<420nm and λ>550nm, as shown in Figure 23(b) . Overall, under one sunlight, PCE increased slightly to 7.2±0.2%.

The OPV battery with BPhen: C ₆₀ /BPhen composite buffer has FF=66±1%, which is an improvement of 18% compared with the control group. In addition, V _OC increased from 0.91±0.1V of the control group to 0.93±0.1V of the battery with BPhen: C ₆₀ /BPhen buffer. However, J _SC decreased to 13.2±0.4 mA/cm ² , which was 5% lower than that of the control group. Overall, the OPV battery with BPhen: C ₆₀ /BPhen buffer exhibited PCE=8.1±0.4% under simulated AM 1.5G and 1 sunlight, an increase of 14% compared to the control battery.

In FIG. 24, the absorption efficiency η _{A of} the organic active region (ie, DBP: C ₇₀ mixed layer and pure C ₇₀ cover layer) is calculated using the transfer matrix method ^{4, 5} and the internal quantum efficiency (IQE) of the two batteries. As previously mentioned ³ , due to the absorption of the BPhen:C ₆₀ mixed buffer, the absorption of the covered buffer battery decreases between λ=350nm and 500nm. At λ>500 nm, the mixed buffer is transparent, and therefore, the two batteries have nearly the same absorption spectrum.

Similarly, the battery with BPhen:C ₆₀ /BPhen buffer had an increased IQE between λ=350 nm and 550 nm compared to the control battery. For example, the IQE of a battery with BPhen: C ₆₀ /BPhen buffer has an EQE of ~90% between λ=350nm and λ=500nm, and reaches ~100% at λ=430nm, indicating that every photon absorbed is converted The charge carriers accumulated by the electrodes.

The responsivity (R) and PCE of the battery with BPhen: C ₆₀ /BPhen filter and the control group were studied as a function of light intensity ranging from 0.4 sunlight to 2.7 sunlight (Figure 25). The response of the battery in the control group decreased monotonously with the intensity, from R=14.9±0.4 A/W under 0.4 sunlight to 13.0±0.4 A/W under 2.7 sunlight, while the battery with filter was The same solar concentration range remains unchanged. As shown in Figure 25, the control battery also showed a roll-off of its PCE with increasing light intensity, which was attributed to the monotonous decrease in responsivity. The PCE of the battery with BPhen: C ₆₀ /BPhen buffer increases slightly under 1 sunlight to reach the maximum value, and then begins to roll off due to the decrease of FF at higher light intensity, which may be due to the enhanced bimolecular recombination at high light intensity Caused by.

The thickness of the mixed buffer layer in the DBP: C ₇₀ PM-HJ battery with BPhen: C ₆₀ /BPhen buffer is also changed. The JV characteristics and EQE spectrum under 1 sunlight illumination are shown in FIG. 26 and the device performance is summarized in Table 8.

J _SC decreases monotonically as the thickness of the mixed buffer increases. As shown in Fig. 26(b), EQE decreases with the thickness of the mixed layer in the entire visible spectrum. V _OC slightly increased from 0.91±0.01V for batteries without a mixed buffer layer to 0.93±0.01V for batteries with a 10nm thick mixed buffer, and remained stable for thicker mixed buffer layers. The FF increased from 0.56±0.01 of the control battery to 0.66±0.01V of the 10nm thick mixed buffer and then rolled off for the thicker mixed buffer, due to the increased series resistance as shown in Table 8.

At the same time, the 3-D Monte Carlo simulation of the nearest-neighbor jump transport in the cubic lattice is used to model the mixed layer as a random distribution of C ₆₀ and BPhen molecules to model charge transport through the mixed buffer layer. Ignore the Coulomb interaction between charges and assume that the lattice sites are isoenergetic except for the energy difference caused by the applied electric field. The Miller-Abrahams table was used to calculate the relative jump probability between sites. In each time interval of the model, the charge chooses random nearest neighbors to jump, weighted by the relative jump probability. If the selected site contains a BPhen molecule, the charge system will remain stationary in terms of this distance. The behavior of the charge in the mixed and pure layers is otherwise the same.

By injecting charge on one side of the 100×100 simulated site lattice and measuring the time for the charge to escape from the opposite side under the electric field, the median extraction time for different thicknesses was calculated. Figure 27 shows the median extraction time versus electric field as a function of the thickness of the mixed layer. Just specify the thickness For the hybrid layer, the electric field accelerates the charge transfer in the hybrid layer, so the median extraction time decreases as the electric field increases. As the thickness of the mixed buffer increases, the charge takes longer to travel through the mixed layer. Therefore, the median extraction time becomes longer as the thickness of the mixed layer increases.

To test the prediction of the model, the series resistance obtained by fitting the JV characteristics in the dark as shown in Table 8 was compared with the value obtained by modeling PM-HJ cells with different mixed layer thicknesses. The mobility of the mixed layer with different thicknesses is calculated from the electrical field dependence of the extraction time and all simulated layers show an effective mobility of 4.7×10 ^-3 cm ² /V‧s, under the electrical field dependence of 1/extraction time . The resistance of this prediction layer should be linearly related to the thickness, as shown in the inset of Figure 27. The predicted mobility of the 1:1 mixed buffer layer is only an order of magnitude lower than that of pure C ₆₀ , which is relatively high for organic substances. This shows how efficiently these layers can extract charge from the pure layer. As shown in previous simulations, these layers effectively block excitons, leading to spatial separation of excitons and polarons to suppress quenching.

Example 20

The device shown in Fig. 28 was produced as explained. The complete structure is glass substrate/ITO (100nm)/MoO ₃ (100nm)/buffer 1/DBP (20nm)/C ₆₀ (40nm)/buffer 2/Ag (100nm), of which buffer 1 and buffer 2 and The corresponding efficiency parameter measurement values are shown in Table 9. Fig. 28 (a) shows a JV illuminated under 1 sunlight simulation AM1.5G illumination, where the illustration shows NPD, and (b) shows the outside of an OPV battery with an active layer including DBP and C ₆₀ and various buffers Quantum efficiency.

The measured values of the thickness, composition and efficiency parameters of each filter are provided in Table 9. Compared to the reference example, a pure layer containing NPD as a filter causes a significant increase in J _SC and a decrease in FF. The use of a 1:1 dopant filter that includes DBP and NPD can improve FF compared to using NPD alone, while still improving J _SC compared to a reference device. Used in conjunction with the electronic filter at the electrode, NDP: DBP hole filter results in a 10% increase in PCE.

Example 21

The device shown in FIG. 30 was produced as illustrated. The complete structure is glass substrate/ITO/MoO ₃ (10 nm)/DBP: C ₇₀ (1:8) (54 nm)/C ₇₀ (9 nm)/buffer/Al (100 nm). This device was grown on a commercially available pre-patterned ITO substrate. A solvent and UV-ozone system are used to clean the substrate. The organic layer, metal oxide and cathode are deposited in a thermal evaporator at a rate of 0.1 nm/sec. The device is then encapsulated by placing an epoxy layer around the device and pressing the glass slide on top. Cures epoxy UV.

In one device, the buffer layer is a mixed layer of BPhen:C ₆₀ (1:1) (10 nm) with a BPhen cover layer (5 nm). In another device, the buffer layer is a mixed layer of TPBI:C ₇₀ (1:1) (10 nm) with a TPBi cover layer (3 nm). It should be noted that other wide band gap materials may be used, such as those listed in Table 10 below and others described above.

To test the life at elevated temperatures, the device was placed in a carrier board made of printed circuit boards. Welding contacts. A resistance heater was used to attach the copper plate to the device to dissipate the heat throughout the device area. Use a thermocouple to measure the temperature. A xenon arc lamp was used to irradiate the device at 1000 W/m ² , and every 30 minutes, a current-voltage source electric meter controlled by a Matlab program was used for measurement.

Figures 31A to C show the standardized performance values of the device using BPhen at various temperatures, and Figures 32A to D show the standardized performance values of the device using TPBi at various temperatures. As shown in FIGS. 31A to C and 32A to D, due to the morphological instability of BPhen as indicated by their respective T _g compared to TPBi, the performance of the device using BPhen in particular increases with temperature. Time degradation is significantly faster than devices using TPBi.

Example 22

The device shown in FIG. 33 was as illustrated and manufactured using the same technique as described in Example 21. The complete structure is a glass substrate with various buffer layers as shown/ITO/MoO ₃ (10nm)/C ₇₀ : DBP(8:1)(54nm)/C ₇₀ (9nm)/buffer (15nm)/Al(100nm ), the buffer layers have a mixed layer of a wide band gap material and an electron conductive material and include a cover layer of a wide band gap material. It should be noted that other wide band gap materials may be used, such as those described above. Figure 33 shows the relative normalized power of devices using BPhen in the buffer layer at 55°C compared to three devices each using a different wide-gap material with a higher _Tg than BPhen (ie, BAlq, 3TPYMB, and TPBi). Conversion efficiency.

As shown in FIG. 33, the performance of a device including a mixed buffer layer with a wide band gap material having a higher _Tg than BPhen is significantly lower in degradation over time. The molecular structures of these materials and the molecular structures of other wide band gap materials Alq ₃ and BP4mPy are shown in FIGS. 34 to 38.

Figures 39 to 41 show the normalized responsivity, fill factor, V _OC, and PCE of the device with a mixed buffer containing C ₇₀ and a mixture with one of TPBi, 3TPYMB, and BAlq, respectively, at 55°C over time. As shown in the figure, the standardized performance values of devices including one of TPBi, 3TPYMB and BAlq (for example, mainly PCE, V _OC , FF and R) and the performance of devices including BPhen (FIGS. 31A to C and FIG. 33 The performance of the BPhen device shown in Figure 1) remains significantly higher than time.

Example 23

106℃)之緩衝層。採用與實例21中所述相同的技術測試裝置在高溫下的壽命。圖43至46顯示圖42的裝置分別在55℃、70℃、85℃及100℃下之隨時間變化之標準化響應度、填充因子、V_OC及PCE。 The device shown in FIG. 42 is as illustrated and made using the same technique as described in Example 21. The complete structure is glass substrate/ITO(160nm)/MoO ₃ (10nm)/C ₇₀ : DBP(8:1)(54nm)/C ₇₀ (9nm)/3TPYMB: C ₆₀ (1:1)(10nm)/Al (100nm). 10nm of 3TPYMN: C ₆₀ layer comprises a wide bandgap material 3TPYMB T _g (3TPYMB of

106℃) buffer layer. The life of the device at high temperature was tested using the same technique as described in Example 21. Figures 43 to 46 show the normalized responsivity, fill factor, V _OC and PCE of the device of Figure 42 over time at 55°C, 70°C, 85°C and 100°C, respectively.

110‧‧‧electrode

115‧‧‧ Excitonic barrier electron/hole filter

120‧‧‧ Donor/Recipient

130‧‧‧ Donor/Recipient

135‧‧‧ exciton shielding electron/hole filter

140‧‧‧electrode

150‧‧‧Photoactive area

160‧‧‧Photoactive area

The drawings are incorporated and form part of this description.

FIG. 1 ((a) and (b)) shows a schematic diagram of an exemplary organic photosensitive optoelectronic device according to the present invention. Device A includes an exciton-barrier electronic filter or exciton-barrier hole filter, and device B includes an exciton-barrier electronic filter and an exciton-barrier hole filter.

)、3：1(▼)、1：1(●)、1：2(■)及0：1(

)體積摻雜比之C₆₀：BCP膜之消光光譜。插圖：消光之衰減成C₆₀分率之函數。450nm(■)，360nm(●)。 Figure 2 shows that calculated from the measured k by spectral ellipsometry with a value of 1:0 (

), 3:1(▼), 1:1(●), 1:2(■) and 0:1(

) C _{60 of} volume doping ratio: extinction spectrum of BCP film. Inset: The attenuation of extinction as a function of C ₆₀ fraction. 450nm (■), 360nm (●).

Figure 3 shows the J-V curve of the device at the top under 1 sunlight AM1.5G. The top inset shows the characteristics of the device, and the bottom figure of the external quantum efficiency. The bottom inset shows the structure of the device. (A:B)=1:0 (D1), 2:1 (D2), 1:1 (D3), and 1:2 (D4).

Figure 4 shows a graph of the J-V curve of the device at the top under 1 sunlight AM1.5G illumination and the external quantum efficiency of the bottom, where the illustration shows the structure of the device. x=10nm (D7), 20nm (D6), 30nm (D5).

Figure 5 shows the J-V curve of the device at the top under 1 sunlight AM1.5G illumination and the external quantum efficiency of the bottom, where the illustration shows the structure of the device. x=0nm (D8), 20nm (D9), and 40nm (D10).

Figure 6 shows the JV curve of the device at the top under 1 sunlight AM1.5G illumination, and the external quantum efficiency at the bottom, where the bottom illustration shows the structure of the device. "First C ₆₀ thickness" refers to the thickness of the at least one acceptor material forming a donor-acceptor heterojunction with DPSQ (x=5nm, 15nm, 25nm, 35nm).

Figure 7 shows the J-V curve of the top device under the illumination of 1 sunlight AM1.5G, and the bottom The external quantum efficiency of the Department, where the bottom illustration shows the structure of the device.

Fig. 8 shows the external quantum efficiency of different buffer layers for EQE normalization under zero bias under applied bias (+0.5V dashed line, -1V solid line).

Figure 9 shows the Monte Carlo simulation of exciton diffusion into the BCP on top of the pure C ₆₀ active layer: C ₆₀ mixed layer, based only on the reduced number of C ₆₀ molecules available in the mixed film for exciton transfer . Excitons are randomly generated in the active layer. They randomly move the distance between the set numbers, and then record their final positions. Assume that excitons only diffuse by nearest neighbor hopping. At the interface between the mixing and active layers, the probability of jumping between layers is measured by the relative number of C ₆₀ molecules in each layer.

Figure 10 shows the normalized extinction spectrum of C ₇₀ covering different buffer layers at the top and the emission spectrum of C ₇₀ (excited at 450 nm) covered by quenching (NPD), barrier (BCP) and mixed buffer layers at the bottom.

Fig. 11 shows the EQE spectrum (top) of the device covering different buffer layers and the J-V curve of the device under 0.8 sunlight AM1.5G illumination.

Fig. 12 shows the JV curve of the device at the top under the illumination of 1 sunlight AM1.5G, and the graph of the external quantum efficiency at the bottom, where the bottom illustration shows the structure of the device. Buffers: 10 nm BCP (D11), 10 nm C ₆₀ : BCP (D12), 10 nm PTCBI (D13), 10 nm C ₆₀ : BCP/5 nm PTCBI (D14), 10 nm BCP: C ₆₀ /5 nm BCP (D15).

Figure 13 shows the EQE of the device of Figure 12 with different buffer layers normalized to 0V EQE at -1V at the top, and the responsivity of the display device at the bottom as a function of the illumination intensity. Buffers: 10nm BCP (D11), 10nm BCP: C 60 (D12), 10nm PTCBI (D13), 10nm BCP: C 60 / 5nm PTCBI (D14), 10nm BCP: C 60 / 5nmBCP (D15).

Fig. 14 shows the J-V curve of the device at the top under 1 sunlight AM1.5G illumination, and a graph of the external quantum efficiency at the bottom, where the bottom illustration shows the structure of the device. x=5nm (D16), 15nm (D17), 25nm (D18), and 35nm (D19).

15 shows a graph of the external quantum efficiency of the J-V curve at the top under 1 sunlight AM1.5G illumination and the devices with different buffer layers at the bottom.

16 shows a graph of the external quantum efficiency of a device with different buffer layers containing different ratios of C ₆₀ to BCP at the bottom and the JV curve at the top under 1 sunlight AM1.5G illumination.

Figure 17 shows the JV (upper left) and EQE of the illumination of a planar hybrid OPV battery with a relatively thick 1:8 volume ratio of DBP and an active layer of pure C ₇₀ layers under 1 sunlight simulated AM1.5G illumination (Upper right) and extraction efficiency parameters (lower). The thickness and volume ratio of BPhen:C _{70 for} each buffer is provided in the table.

Figure 18 shows the JV (top left) of a planar hybrid OPV battery with an active layer including a relatively thin 1:8 volume ratio of DBP and pure C ₇₀ layers and various buffers under 0.7 sunlight simulated AM1.5G illumination Picture) and EQE (upper right picture) and extraction efficiency parameters (below). The thickness and volume ratio of BCP:C _{70 for} each buffer is provided in the table.

Figure 19 ((a), (b) and (c)) shows the EQE and J-V curves diluted with BPhen, CBP and UGH2.

Figure 20(a) shows the spectrally corrected current density relative voltage (JV) characteristics of DBP: C ₇₀ hybrid-HJ OPV battery under simulated AM 1.5G and 1 sunlight. The shaded area highlights the difference in the fill factor (and therefore maximum power output) of the two batteries. The inset shows a schematic diagram of the structure of the device, and (b) shows the external quantum efficiency (EQE) spectrum of the battery in (a). The inset shows a schematic diagram of the energy levels at the DBP: C ₇₀ /buffer interface (left: pure BPhen buffer; right: BPhen: C ₆₀ composite buffer).

Fig. 21 shows the relative light intensity of the hybrid-HJ control battery and the composite buffer battery with a linear fit (dashed line) according to the bimolecular recombination theory.

Fig. 22(a) shows the relative electric field of charge extraction time of different layer thicknesses calculated by 3-D Monte Carlo simulation. The inset shows the battery series resistance (R _S) and the data relative to the layer thickness (squares) OPV cells obtained from the linear fit of the (broken line) (Error bars are smaller than the data points of the illustration), and (b) shown in the λ = The photoluminescence (PL) spectrum of a pure C ₇₀ layer in contact with BPhen (barrier), NPD (quenching) and BPhen: C ₆₀ mixed layer at an excitation wavelength of 520 nm.

Figure 23 (a) shows the characteristics of the spectral corrected current density relative voltage (JV) under simulated AM 1.5G and 1 sunlight, and (b) shows the DBP with different buffer layers: C ₇₀ PM-HJ OPV battery. External quantum efficiency spectrum.

Figure 24 shows the calculated values of the absorption spectrum and the calculated internal quantum efficiency of the control battery and the battery with BPhen: C ₆₀ /BPhen buffer.

FIG. 25 shows the response light intensity (solid square) and power conversion efficiency (open square) of the control battery and the battery with BPhen: C ₆₀ /BPhen buffer relative to the light intensity.

Fig. 26 (a) shows the spectrally corrected JV characteristics under simulated AM 1.5G and 1 sunlight, and (b) shows the external quantum efficiency spectrum in the battery with BPhen: C ₆₀ /BPhen buffer to BPhen: C ₆₀ as a function of the thickness of the mixed layer.

Figure 27 shows the modeled median extraction time versus electric field as a function of BPhen:C ₆₀ mixed layer thickness, and the inset shows the series resistance relative to the mixed layer thickness and fit.

Fig. 28 (a) shows a JV illuminated under 1 sunlight simulation AM1.5G illumination, where the illustration shows NPD, and (b) shows the outside of an OPV battery with an active layer including DBP and C ₆₀ and various buffers Quantum efficiency.

29 ((a) and (b)) show schematic diagrams of an exemplary tandem organic photosensitive optoelectronic device according to the present invention. Device A includes an exciton-barrier electronic filter or exciton-barrier hole filter, and device B includes an exciton-barrier electronic filter and an exciton-barrier hole filter.

Figure 30 shows a mixed BPhen with a thin BPhen cover layer (5 nm) between the mixed buffer layer and the Al electrode: C ₆₀ buffer layer (10 nm), or a thin TPBi cover layer (3 nm) between the mixed buffer layer and the Al electrode The mixed TPBi: C ₇₀ buffer layer (10 nm) DBP: C ₇₀ device.

FIGS. 31A to 31C show the normalized responsivity, fill factor, V _OC and time-varying variation of the device of FIG. 30 with a mixed Bphen:C ₆₀ buffer layer with a thin BPhen cover layer at 50°C, 60°C, and 80°C, respectively. PCE.

FIGS. 32A to 32D show the normalized responsivity, fill factor, and time-varying variation of the device of FIG. 30 with a mixed TPBi:C ₆₀ buffer layer with a thin TPBi cover layer at 50°C, 80°C, 105°C, and 130°C V _OC and PCE.

Figure 33 shows the standardized power conversion efficiency of DBP: C ₇₀ hybrid heterojunction with various buffers over time.

34 to 38 show the molecular structures of exemplary wide band gap materials BAlq, TPBi, Alq ₃ , BP4mPy, and 3TPYMB, respectively.

Figures 39 to 41 show the normalized responsivity, fill factor, V _OC, and PCE of the device with a mixed buffer containing C ₇₀ and a mixture with one of TPBi, 3TPYMB, and BAlq, respectively, at 55°C over time.

Figure 42 shows a DBP: C ₇₀ device with a mixed 3TPYMB: C ₆₀ buffer layer.

Figures 43 to 46 show the normalized responsivity, fill factor, V _OC and PCE of the device of Figure 42 over time at 55°C, 70°C, 85°C and 100°C, respectively.

110‧‧‧electrode

115‧‧‧ Excitonic barrier electron/hole filter

120‧‧‧ Donor/Recipient

130‧‧‧ Donor/Recipient

135‧‧‧ exciton shielding electron/hole filter

140‧‧‧electrode

Claims (33)

An organic photosensitive optoelectronic device, comprising: two electrodes including an anode and a cathode in a stacked relationship; including at least one donor material and at least one acceptor material disposed between the two electrodes to form a donor-receiver A photoactive region of a bulk heterojunction, wherein the at least one acceptor material has the lowest unoccupied molecular orbital energy level (LUMO _Acc ) and the highest occupied molecular orbital energy level (HOMO _Acc ); and is disposed at the cathode and the at least one An exciton barrier electronic filter between acceptor materials, wherein the electronic filter includes a mixture comprising at least one cathode side wide band gap material and at least one electron conducting material, wherein the at least one cathode side wide band gap material has : Less than or equal to the lowest unoccupied molecular orbital energy level of the LUMO _Acc (LUMO _CS-WG ); greater than, equal to, or less than the highest occupied molecular orbital energy level of HOMO _Acc (HOMO _CS-WG ) within _0.3eV ; HOMO _CS-WG -LUMO _CS-WG energy gap wider than the HOMO _Acc -LUMO _Acc energy gap; and glass transition temperature equal to or higher than 85°C; and the lowest unoccupied molecular orbital energy of the at least one electron conducting material The order (LUMO _EC ) is greater than, equal to, or less than the LUMO _Acc within 0.2 eV. The device of claim 1, wherein the at least one cathode side wide energy gap material includes a material selected from the group consisting of: 3,3',5,5'-tetra[(m-pyridyl)-phenyl-3-yl] Benzene (BP4mPy), 2,2',2"-(1,3,5-Petroleum triphenyl (Benzinetriyl))-ginseng (1-phenyl-1-H-benzimidazole) (TPBi), bis( 2-methyl-8-hydroxyquinoline)-4-(phenylbenzyl alcohol) aluminum (BAlq), ginseng (8-hydroxy-quinoline) aluminum (Alq3), ginseng (2,4,6-trimethyl 3-(pyridin-3-yl)phenyl)borane (3TPYMB), 4,40-(1,3-phenylene)bis(2,6-di-p-tolylpyridine-3,5- Second Class Nitrile) (m-MPyCN), 4,40-(1,3-phenylene)bis(2,6-bis(biphenyl-4-yl)pyridine-3,5-dicarbonitrile) (m-PhPyCN ), 4,40-(1,3-phenylene)bis(2,6-diphenylpyridine-3,5-dicarbonitrile) (m-PyCN), 6,60-(1,4-extrude Phenyl)bis(2-phenyl-4-p-tolylnicotinonitrile) (p-PPtNN), 4,40-(1,4-phenylene)bis(2-phenyl-6-p- Toluyl nicotinic nitrile) (p-PPtNT) and its derivatives. The device of claim 1, wherein the at least one cathode side wide energy gap material has a glass transition temperature between 85 and 200°C. The device of claim 1, wherein the at least one cathode side wide energy gap material has a glass transition temperature between 100 and 165°C. The device of claim 1, wherein the HOMO _CS-WG is larger than the HOMO _Acc , and the LUMO _CS-WG is smaller than the LUMO _Acc . The device of claim 1, wherein the LUMO _EC is equal to the LUMO _Acc . The device of claim 1, wherein the LUMO _EC is greater than the LUMO _Acc . The device of claim 1, wherein the LUMO _CS-WG is smaller than the LUMO _EC . The device of claim 1, wherein the at least one acceptor material includes a material selected from the group consisting of phthalocyanine, naphthalene phthalocyanine, dipyrrin complex, BODIPY complex, perylene, naphthalene, Fullerenes, functionalized fullerene derivatives and their derivatives. The device of claim 9, wherein the at least one acceptor material includes a material selected from fullerenes and functionalized fullerene derivatives. The device of claim 1, wherein the at least one electron-conducting material includes a material selected from the group consisting of phthalocyanine, naphthalene phthalocyanine, dipyrrolmethene complex, BODIPY complex, perylene, naphthalene, and fullerene , Functionalized fullerene derivatives and their derivatives. The device of claim 1, wherein the at least one acceptor material and the at least one electron conducting material include the same material. The device of claim 1, wherein the mixture comprises the at least one cathode-side wide bandgap material by volume and the at least one electron conduction in a ratio ranging from 10:1 to 1:10 material. The device of claim 1, wherein the mixture comprises the at least one cathode-side wide bandgap material and the at least one electron conductive material in a ratio ranging from 2:1 to 1:2 by volume. The device of claim 1, further comprising at least one cover layer disposed between the exciton-barrier electronic filter and the cathode. The device of claim 15, wherein the at least one cover layer and the at least one cathode side wide band gap material include the same material. The device of claim 1, wherein the at least one electron conductive material comprises a material selected from fullerenes and functionalized fullerene derivatives. The device of claim 17, wherein the at least one electron conductive material comprises a material selected from C ₆₀ and C ₇₀ . The device of claim 18, wherein the at least one acceptor material comprises a material selected from C ₆₀ and C ₇₀ . The device of claim 18, wherein the at least one cathode side wide energy gap material comprises a material selected from BP4mPy, TPBi, BAlq, Alq3, and 3TPYMB. The device according to claim 20, further comprising at least one cover layer disposed between the exciton-barrier electronic filter and the cathode, wherein the at least one cover layer includes one selected from BP4mPy, TPBi, BAlq, Alq3, and 3TPYMB material. The device of claim 19, wherein the at least one cathode side wide energy gap material comprises TPBi. The device of claim 22, further comprising at least one cover layer disposed between the exciton-barrier electronic filter and the cathode, wherein the at least one cover layer includes TPBi. The device of claim 23, wherein the at least one donor material comprises tetraphenyldibenzodiindenopyrene (DBP). The device of claim 1, wherein the at least one cathode side wide energy gap material comprises TPBi. An organic photosensitive optoelectronic device, comprising: two electrodes in an overlapping relationship including an anode and a cathode; at least one donor material disposed between the two electrodes to form a donor-acceptor heterojunction and At least one photoactive region of the acceptor material, wherein the at least one donor material has the lowest unoccupied molecular orbital energy level (LUMO _don ) and the highest occupied molecular orbital energy level (HOMO _don ); and is disposed on the anode and the An exciton-barrier hole filter between at least one donor material, wherein the hole filter includes a mixture comprising at least one anode side wide band gap material and at least one hole conductive material, wherein the at least one anode side wide The energy gap material has: greater than or equal to the highest occupied molecular orbital energy level (HOMO _AS-WG ) of the HOMO _don ; less than, equal to, or greater than the lowest unoccupied molecular orbital energy level (LUMO) of the LUMO _don within 0.3eV _AS-WG ); HOMO _AS-WG- LUMO _AS-WG energy gap wider than HOMO _Don- LUMO _Don energy gap; and glass transition temperature equal to or higher than 85℃. The device of claim 26, wherein the at least one anode-side wide energy gap material includes a material selected from the group consisting of: 3,3',5,5'-tetra[(m-pyridyl)-phenyl-3-yl] Benzene (BP4mPy), 2,2',2"-(1,3,5-petroleum triyl)-ginseng (1-phenyl-1-H-benzimidazole) (TPBi), bis(2-methyl Yl-8-hydroxyquinolinate)-4-(phenylbenzyl alcohol) aluminum (BAlq), ginseng (8-hydroxy-quinoline) aluminum (Alq3), ginseng (2,4,6-trimethyl-3 -(Pyridin-3-yl)phenyl)borane (3TPYMB), 4,40-(1,3-phenylene)bis(2,6-di-p-tolylpyridine-3,5-dicarbonitrile ) (m-MPyCN), 4,40-(1,3-phenylene)bis(2,6-bis(biphenyl-4-yl)pyridine-3,5-dicarbonitrile) (m-PhPyCN) 、4,40-(1,3-Phenylphenyl)bis(2,6-diphenylpyridine-3,5- Dicarbonitrile) (m-PyCN), 6,60-(1,4-phenylene)bis(2-phenyl-4-p-tolylnicotinonitrile) (p-PPtNN), 4,40- (1,4-Phenylphenyl)bis(2-phenyl-6-p-tolylnicotinonitrile) (p-PPtNT) and its derivatives. The device of claim 26, wherein the at least one anode side wide energy gap material has a glass transition temperature between 85 and 200°C. The device of claim 26, wherein the HOMO _AS-WG is larger than the HOMO _don , and the LUMO _AS-WG is smaller than the LUMO _don . The device of claim 26, wherein the HOMO _HC is equal to or less than the HOMO _don . The device of claim 26, wherein the HOMO _AS-WG is larger than the HOMO _HC . The device of claim 26, wherein the at least one donor material includes a material selected from the group consisting of phthalocyanine, subphthalocyanine, naphthalocyanine, merocyanine dye, boron-dipyrrolidine (BODIPY) dye, thiophene, and low energy Band gap polymer, polyacene, diindenoperylene (DIP), squaric acid (SQ) dye, tetraphenyldibenzodiindenopyrene (DBP) and its derivatives. The device of claim 26, wherein the at least one hole conductive material includes a material selected from the group consisting of phthalocyanine, subphthalocyanine, naphthalocyanine, merocyanine dye, boron-dipyrrolidine (BODIPY) dye, thiophene, Low-energy band gap polymer, polyacene, diindenoperylene (DIP), squaric acid (SQ) dye, tetraphenyldibenzodiindenopyrene (DBP) and its derivatives.

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