JPH0548131A - Photoelectric conversion element - Google Patents

Abstract

PURPOSE:To provide a photoelectric conversion element which can reduce its resistance at the connecting section between the second back electrode film and light receiving surface electrode film. CONSTITUTION:Conductive paste 6 is applied to the surface of a light- transmissive light receiving surface electrode film 1 and, at the same time, a semiconductor film 2 containing an optical active layer and the first back electrode film 3 are formed at intervals around the paste 6. In addition, an insulating film 4 is formed on the electrode film 3 and between the paste 6 and the films 2 and 3. The second back electrode film 5 is formed on the insulating film 4 and the electrode film 5 is connected to the paste 6 extended onto the insulating film 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion element that generates electromotive force by receiving light irradiation.

[0002]

2. Description of the Related Art In a conventional photoelectric conversion element, a light-receiving surface electrode is made of indium (In) or tin (Sn) so as to exhibit translucency.
Of the oxide of In ₂ O ₅ , SnO ₂ , ITO and the like. Since the sheet resistance of the electrode made of TCO is higher than that of the metal material by three digits or more, the power loss at this electrode was a cause of reducing the current collection efficiency.

In view of this decrease in current collecting efficiency, a method of providing a metal grid-shaped collecting electrode on the light receiving surface side has been developed as in the conventional single crystal solar cell or Japanese Patent Laid-Open No. 59-50576. .

However, the metal grid-shaped collecting electrode is
Although the resistance is lower than that of the transparent electrode, a part of the irradiation light that should reach the photoactive layer is blocked, so that the effective light receiving area where the photoelectric conversion operation is effectively performed is unavoidable.

Therefore, the applicant of the present invention, although using a high resistance TCO or a metal thin film as the light-receiving surface electrode, does not significantly reduce the effective light-receiving area unlike the structure in which a grid-shaped collecting electrode is added. A structure for reducing resistance loss due to the light-receiving surface electrode has been developed and has already been applied for (Japanese Patent Laid-Open No. 61-20371 and Japanese Utility Model Laid-Open No. 61-86955).
(See the official gazette).

FIG. 3 shows a conventional technique developed by the applicant. In this photoelectric conversion element, as compared with the light-receiving surface electrode film 1, the semiconductor film 2 including a photoactive layer, the first back electrode film 3 of ohmic metal, the insulating film 4, and the light-receiving surface electrode film 1 when viewed from the light incident side. The second back electrode film 5 having a low resistance is superposed, and the second back electrode film 5 is embedded in the contact holes 7 whose inner periphery is surrounded by the insulating film 4 at a plurality of positions in the light receiving region. The film 1 and the second back electrode film 5 are electrically coupled.

Since the high resistance light receiving surface electrode film 1 and the low resistance second back electrode film 5 are electrically coupled at a plurality of points, the current paths of the currents flowing through the light receiving surface electrode film 1 are close to each other. As a result of the reduction to the coupling portion, the resistance loss due to the light-receiving surface electrode can be reduced without significantly reducing the effective light-receiving area.

[0008]

However, in the above-mentioned conventional technique, the resistance of the connection portion between the second back electrode film 5 and the light-receiving surface electrode film 1 is large, and power loss here becomes a problem.

An object of the present invention is to provide a photoelectric conversion element capable of reducing the resistance of the connecting portion between the second back electrode film and the light receiving surface electrode film described above.

[0010]

A photoelectric conversion element according to the present invention has a conductive paste formed on a light-transmitting light-receiving surface electrode film, and includes a photoactive layer at intervals around the conductive paste. The semiconductor film and the first back electrode film are formed, and the insulating film is formed on the first back electrode film and between the conductive paste and the semiconductor film and the first back electrode film. The second back electrode film is formed, and the second back electrode film is connected to the conductive paste extending on the insulating film.

[0011]

The resistance of the connecting portion between the conductive paste and the light-receiving surface electrode film and the resistance of the connecting portion between the conductive paste and the second back electrode film are the same as those of the conventional light receiving surface electrode film and the second back electrode film. Since the resistance of the connection part between the light-receiving surface electrode film and the second back electrode film when connected via the second back electrode film in the contact hole is three digits or more, the resistance of the connection part should be extremely small. Is possible.

[0012]

EXAMPLE FIG. 1 shows the structure of a photoelectric conversion element.

In FIG. 1, 10 is a glass substrate, 1 is a light-receiving surface electrode film, 6 is a conductive paste, 2 is a semiconductor film including a photoactive layer, 3 is a first back electrode film, 4 is an insulating film, and 5 is an insulating film. Second
It is a back electrode film.

This photoelectric conversion element is manufactured as follows. First, the transparent conductive oxide (T
A light receiving surface electrode film 1 such as CO) is formed, and a conductive paste 6 such as Ag paste is printed and fired on the light receiving surface electrode film 1 in an island shape. Next, on the light-receiving surface electrode film 1, a semiconductor film 2 mainly composed of, for example, amorphous silicon and a first back electrode film 3 including a photoactive layer parallel to the film surface are sequentially formed, and a conductive paste 6 is formed. The semiconductor film 2 and the first back electrode film 3 are processed and removed by a laser beam or the like so as to surround the outer periphery with a space.

Next, an insulating film 4 is formed on the first back electrode film 3 and between the semiconductor film 2 and the first back electrode film 3 and the conductive paste 6, and the conductive paste 6 is again formed by a laser beam or the like. It is exposed on the insulating film 4. Finally, the second back electrode film 5 is formed on the insulating film 4 and connected to the conductive paste 6 such as Ag paste.

In this embodiment, the light-receiving surface electrode film 1 and the second back electrode film 5 are electrically connected via a conductive paste 6 such as Ag paste formed on the light-receiving surface electrode film 1. There is. The resistance of the connecting portion between the conductive paste 6 and the light receiving surface electrode film 1 and the resistance of the connecting portion between the conductive paste 6 and the second back electrode film 5 are the same as those in the conventional case. Since the resistance of the connection portion between the light-receiving surface electrode film and the second back surface electrode film is smaller by three digits or more when and are connected through the second back surface electrode film in the contact hole, the resistance of the connection portion is made extremely small. It is possible.

FIG. 2 shows the second back surface when the thickness of the light-receiving surface electrode film 1 is changed with the outer diameter of the conductive paste 6 in the above embodiment being 100 μm (in the conventional structure, the inner diameter of the contact hole is 100 μm). The result of calculation of the resistance value of the connection portion between the electrode film 5 and the light-receiving surface electrode film 1 by simulation is shown together with the resistance value of the connection portion of the conventional structure. In FIG. 2, the solid line shows the resistance of the connection portion of the above-mentioned embodiment, and the chain line shows the resistance of the connection portion of the conventional example. From FIG. 2, it can be seen that the resistance of the connecting portion is reduced by 2 to 3 digits by using the structure of the present invention as compared with the conventional structure.

[0018]

According to the present invention, the light-receiving surface electrode film and the second
Since the resistance at the connection with the back electrode film is smaller than that of the conventional structure, the output loss at this connection can be reduced and the photoelectric conversion efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a photoelectric conversion element showing an embodiment of the present invention.

FIG. 2 is a graph showing a resistance value of a connection portion between a light-receiving surface electrode film and a second back electrode film in an example of the present invention and a conventional example obtained by calculation.

FIG. 3 is a cross-sectional view of a conventional photoelectric conversion element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light-receiving surface electrode film 2 Semiconductor film including a photoactive layer 3 First back electrode film 4 Insulating film 5 Second back electrode film 6 Conductive paste

Claims (1)

[Claims] 1. A conductive paste is formed on a light-transmitting light-receiving surface electrode film, and a semiconductor film including a photoactive layer and a first back electrode film are formed around the conductive paste at intervals. An insulating film is formed on the first back electrode film and between the conductive paste and the semiconductor film and the first back electrode film, and a second back electrode film is formed on the insulating film. A photoelectric conversion element in which a back electrode film is connected to a conductive paste extending on an insulating film.