JPH0697474A - Photoelectric conversion device - Google Patents

Abstract

PURPOSE:To prevent a substrate from being deformed and distorted by providing an output end through which an output of a photoelectric conversion device is derivable on a surface of a substrate located oppositely to a surface where the photoelectric conversion device is provided. CONSTITUTION:An output of a photoelectric conversion unit 101 on the side of a substrate is simultaneously derived on a pljotoelectric conversion layer in a formation process of a second electrode 7 upon constructing an integrated structure, and is connected with a derivation electrode 15. In contrast, an output of a second electrode of a photoelectric conversion unit 103 is connected with a derivation electrode 14 yieled by extending the second electrode 7. The derivation electrodes 14, 15 are connected with an output end 13 provided on the back througli a conduction part 12 of a conduction hole 11 provided through a photoelectric conversion device constituting material located below the substrate. The conduction part 12 is provided with the same material as that of the second electrode '7. Hereby, the photoelectric conversion device alloits output lqo be derived through the output 13 provided oppositely to photoelectric conversion device of the substrate 1 to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel structure of a photoelectric conversion device, and more particularly to a photoelectric conversion device using a flexible substrate having low heat resistance.

[0002]

2. Description of the Related Art There is an increasing demand in the market for miniaturization, thinning, and weight reduction of electronic / electrical parts and the like, and a wide variety of materials are being used to form these parts. Photoelectric conversion devices such as solar cells are no exception to this, and devices with various specifications have been proposed. Among these, thin and lightweight products that use flexible organic films and thin metal plates as substrate materials have begun to be noticed on the assumption that they are applied to other electrical products, industrial machinery products, etc. .

Among such flexible substrates, a photoelectric conversion device using a substrate made of an organic material is drawing attention from the viewpoints of cost, characteristics, and workability, and is becoming the mainstream of photoelectric conversion devices for flexible substrates. . The organic material substrate of the flexible substrate has many advantages such as good workability and light weight as compared with the thin metal substrate.

As an example of a photoelectric conversion device using such a flexible substrate made of an organic material, FIG. 7 shows a schematic structure thereof. Although the photoelectric conversion device is formed on the flexible substrate 1, this figure shows a structure in which three photoelectric conversion elements are integrated in series. Each photoelectric conversion element includes a first electrode 71, a non-single-crystal semiconductor layer 72 and a second electrode 73,
And 74. In this example, light is emitted from the second electrode side, and therefore the second electrode is composed of the translucent electrode material ITO 73 and the grid-shaped auxiliary electrode 74.

The second electrode 74 is connected to the adjacent first electrode 71 of the photoelectric conversion element, and each element is connected in series. The output of such a photoelectric conversion device is taken out from the copper lead 75 to the outside. This lead is fixedly connected to the second electrode by soldering.

[0006]

Such a flexible substrate such as an organic material having no heat resistance has sufficient heat resistance as compared with other substrate materials. Not not. Even polyimide film that is said to have high heat resistance is 30
It was about 0 to 350 ° C. Therefore, when manufacturing a photoelectric conversion device, a method of avoiding application of heat as much as possible is adopted and put into practical use. However, after forming the photoelectric conversion device, soldering is generally used when forming the output take-out portion that must be provided when using the photoelectric conversion device. ,
It was necessary to apply heat locally.

Therefore, there is a problem that only a part of the organic material of the flexible substrate is subjected to extreme heat, and only this part is thermally deformed. Also, at a temperature at which thermal deformation does not occur, the leads are not heated. If the connection between the electrode and the electrode of the photoelectric conversion device is made, the connection portion will not have sufficient adhesive strength this time, and conduction failure or peeling of the adhesive portion will occur, causing concern about reliability. There has been a demand for improvement of this output extraction part.

[0008]

(First Invention) The present invention is a thin film photoelectric conversion device provided on a substrate having no heat resistance, and an output capable of taking out the output of the photoelectric conversion device. The end is provided on the surface of the substrate opposite to the surface on which the photoelectric conversion device is provided, and the photoelectric conversion device has a conduction portion that electrically connects the electrode of the photoelectric conversion device and the output end. (2nd invention) Moreover, in the said photoelectric conversion apparatus, a photoelectric conversion apparatus in which the said conduction | electrical_connection part exists in the conduction hole provided in the flexible substrate. (Third invention) Furthermore, in the above photoelectric conversion device, the conductive portion is present on the end surface of the flexible substrate. (Fourth invention) The present invention is a thin-film photoelectric conversion device provided on a substrate having no heat resistance, wherein an output end from which the output of the photoelectric conversion device can be taken out is the photoelectric conversion device of the substrate. Is provided on a surface opposite to the surface provided with, the conducting portion for conducting the electrode of the photoelectric conversion device and the output end is a material used for a part of the electrode of the photoelectric conversion device. A photoelectric conversion device characterized by being the same.

That is, any of the above-mentioned configurations of the present invention is necessary for taking out the output of the photoelectric conversion device to the outside.
When the extraction lead is installed in the photoelectric conversion device, the bonding of the lead and the electrical connection between the lead and the electrode of the photoelectric conversion device are performed separately, and sufficient adhesive strength is achieved without applying a local high temperature. It was done. Therefore, an output end for output extraction is provided on the surface of the substrate opposite to the photoelectric conversion device, the substrate and the output end are fixed, and the fixed output end and the electrode of the photoelectric conversion device are electrically connected by a conductive material. It is a thing. This makes it possible to provide an output end having sufficient adhesive strength without applying excessive heat to the substrate having no heat resistance. The present invention will be described below with reference to examples.

[0010]

[Embodiment 1] FIG. 1A shows an example of an integrated photoelectric conversion device of this embodiment. It has a plastic film substrate 1, a first electrode 2, a PIN type photoelectric conversion layer 3, second electrodes 6 and 7, and insulators 4 and 5 made of an epoxy resin which is an insulator.

Here, each of 101, 102 and 103 constitutes one unit element of the photoelectric conversion device. Then, the second electrode 7 of the photoelectric conversion unit 101 and the first electrode 2 of the photoelectric conversion unit 102 are electrically connected by the connecting portion 9. Moreover, the photoelectric conversion unit 101 and the second photoelectric conversion unit 102 are formed by the first groove 8.
Is insulated from the first electrode and the photoelectric conversion layer of
The second electrode 6 is insulated from each other by the groove 10 formed by laser scribing.

The output of the photoelectric conversion unit 101 on the substrate side is simultaneously led out on the photoelectric conversion layer and connected to the lead electrode 15 in the step of forming the second electrode 7 in the integrated structure. . On the other hand, the output of the second electrode of the photoelectric conversion unit 103 is connected to the lead-out electrode 14 obtained by extending the second electrode 7.

In the photoelectric conversion device according to the present embodiment, the lead-out electrodes 14 and 15 are provided on the back surface by the conduction portion 12 of the conduction hole 11 provided through both the photoelectric conversion device constituent material below and the substrate. Is connected to the output terminal 13 provided. The conducting portion 12 is made of the same material as the constituent material of the second electrode 7. As a result, the photoelectric conversion device of this embodiment can take out its output from the output end 13 provided on the surface of the substrate 1 opposite to the photoelectric conversion element.

The manufacturing process of the photoelectric conversion device of this embodiment will be described below with reference to FIGS. First, a Cr film is formed as a first electrode 2 on a plastic film substrate (hereinafter simply referred to as a substrate) 1 which is a flexible substrate having a thickness of 2000 Å by a sputtering method. In this example, polyethylene terephthalate was used as the plastic film substrate.

The Cr film was formed by using a DC magnetron sputtering device under the following film forming conditions. Argon partial pressure 6 × 10 ^-3 Torr DC current 1A Substrate temperature No heating

After that, the photoelectric conversion layer 3 of non-single crystal silicon is formed on the Cr film. This photoelectric conversion layer is not limited in any way, but considering the heat resistance of the plastic film substrate, a method capable of forming at a substrate temperature of 100 ° C. or less is preferable.

In this embodiment, as the photoelectric conversion layer 3, a non-single-crystal silicon semiconductor is formed in this order from the substrate side in the order of N-type, I-type and P-type, and a PIN-type photoelectric conversion layer (total of 4500Å).
Thickness). The production was performed using the plasma CVD method under the following conditions.

Manufacturing conditions of the N-type semiconductor layer (400 Å thickness). Substrate temperature 80 ° C. RF power 10 W (13.56 MHz) Film forming pressure 0.04 Torr Gas flow rate SiH ₄ = 15 sccm (containing PH ₃ 1%) H ₂ = 150 sccm I-type semiconductor layer (4000 Å thickness) manufacturing conditions. Substrate temperature 80 ° C. RF power 10 W (13.56 MHz) Film formation pressure 0.04 Torr Gas flow rate SiH ₄ = 15 sccm H ₂ = 150 sccm P-type semiconductor layer (100 Å thickness) film formation conditions. Substrate temperature 80 ° C. RF power 10 W (13.56 MHz) Film formation pressure 0.04 Torr Gas flow rate SiH ₄ = 16 sccm (B ₂ H ₆ 1%
Contained) CH ₄ = 18 sccm H ₂ = 145 sccm

When the state of FIG. 2 is obtained in this way, the first method is performed by the laser scribing method (processing method using laser light).
The first open groove 8 is formed at four places of the laminated body including the electrode 2 and the photoelectric conversion layer 3. This laser scribing was performed under the following conditions using a KrF excimer laser (wavelength 248 nm). 1.0 J / cm ² × 7 shots for the first groove

Further, in the present embodiment, a laser beam formed by a linear optical system was used to perform linear laser processing with one shot. However, the spot beam is operated linearly. A method of processing may be used.

As the type of laser light for performing laser scribing, ArF excimer laser, XeF excimer laser, YAG laser (spot processing) or the like can be used depending on the application. As described above, the wavelength of the laser light is preferably 600 nm or less, but the YAG laser (wavelength 1.06 μm)
But it can be used.

What is important here is that, unlike the prior art, by performing laser scribing in a state where the first electrode 2 and the photoelectric conversion layer 3 are laminated, peeling of the first electrode from the plastic film substrate during laser scribing,
It has a remarkable feature that the generation of flakes and flakes can be significantly suppressed.

Next, as shown in FIG. 2, epoxy resins 4 and 5 which are insulators are screened to 2 μm to 2 μm.
It was provided at a predetermined position with a thickness of 0 μm. In this way, by forming these into a predetermined pattern, the first opening 8 is filled with the epoxy resin 4 which is an insulator, and at the same time, the layer 5 of an insulator made of an epoxy resin is provided on the photoelectric conversion layer 3. . Here, by using the screen printing method, the insulating material 4 and the insulating material layer 5 can be formed at the same time, and the remarkable effect that the patterning process, which is one of the major causes of defects, is simplified. Can be obtained.
Further, since the patterning process only needs to process the above-mentioned insulator with the configuration of the present invention, it is possible to suppress the occurrence of defects in the patterning process of the insulator by using the screen printing method as described above. It has a great effect on improving the yield of.

Further, here, the epoxy resin is used as the insulator because it is easy to process, but it is not particularly limited as long as it is an insulator, and silicon oxide, and further organic materials such as polyimide and silicon rubber can be used. Resin, urethane, acrylic, etc. can be used. However, since the laser light will be irradiated during the subsequent laser scribing step, it is preferable that it has heat resistance to the extent that it is not burned out or sublimated by irradiation with a weak laser light. A material that completely penetrates through is not preferable.

In this way, the state shown in FIG. 3 is obtained. The actual positions of the groove 8 and further the insulators 4 and 5 are determined by the accuracy of the patterning process (screen printing method in this embodiment) and the laser scribing process, and are limited to the distance relationship shown in the figure. It goes without saying that this is not what is done.

After obtaining the state shown in FIG.
A film is formed to a thickness of 00Å. As the material used for the second electrode, an ITO film was formed by vacuum evaporation in this embodiment, but other materials such as SnO ₂ and ZnO may be used as long as they have a light-transmitting property. May be. Also,
There are various forming methods, but when using a plastic film substrate having poor heat resistance as in this embodiment,
A low temperature film forming method that does not damage the substrate by heat is preferable.

Next, the second electrode 6 formed on the insulator layer 5 is cut by forming a groove 10 by a laser scribing method to obtain the state shown in FIG. At this time, it is important that the insulating layer 5 serves as a shield so that the laser light does not reach the photoelectric conversion layer 3. Conventionally, in the laser scribing step of cutting only the transparent conductive film, the lower photoelectric conversion layer 3 and the first electrode 2 are often processed together, which causes alloying in this region and a short circuit. Problems such as occurrence have occurred, making integration difficult. However, since the insulating layer 5 is damaged by the laser light when the structure shown in this embodiment is adopted, this layer substantially serves as a barrier and the photoelectric conversion layer 3 is cut by the laser scribe. In addition, the back electrode can be cut without fail, and the reproducibility of the process and the yield were extremely excellent.

After that, a conduction hole 11 penetrating the second electrode 6, the photoelectric conversion layer 3, the first electrode 2 and the substrate 1 is formed by laser light in the peripheral portion of the photoelectric conversion element. Since the conduction hole 11 penetrates to the substrate, it is necessary to extend the substrate to the extent that the substrate can be held. In this embodiment, the total area of the conduction holes is about 30% of the peripheral conduction region. Multiple locations were formed using a YAG laser.

Next, a copper thin plate 13 was fixed on the surface of the substrate opposite to the portion where the through holes were provided by using an epoxy adhesive, except for the through holes. Then, as a part of the second electrode, the grid-shaped auxiliary electrode 7 is provided with the second electrode 6.
Provide on top. The auxiliary electrode 7 is formed in a comb shape on the light receiving surface, and is formed in a bar shape on almost the entire surface in the vicinity of the connection portion with the adjacent element.

The pattern of the auxiliary electrode 7 is improved so that it is formed near the conduction hole 11 around the photoelectric conversion element, and the lead-out electrode portions 14 and 15 are provided. This auxiliary electrode 7 uses silver paste, and is screen-printed in a predetermined pattern.
It is formed. Thereby, the conducting portion 12 is provided and the state shown in FIG. 5 is obtained. This auxiliary electrode 7 is subjected to heat treatment at 100 ° C. for 50 minutes and fired to complete the auxiliary electrode 7 and form the conducting portion 12, and the output of the photoelectric conversion device is output from the output end 13 provided on the back surface of the substrate. Make it accessible.

Next, the second electrodes 6 and 7 on which the auxiliary electrode is formed are connected to the first electrode of the adjacent photoelectric conversion element unit. Laser light is used for this connection, and YAG laser light is irradiated from the second electrodes 6 and 7 side to melt and diffuse the second electrode component, penetrate the semiconductor layer 3, and pass through the first electrode. It is connected to the electrode of. The irradiation condition of the laser light irradiated for this connection is to use YAG laser light with a wavelength of 1.06 μm. The laser Q switch has an oscillation frequency of 2 KHz and energy of 0.2 W, and the portion that conducts electricity is 10 mm / sec. By scanning at the scanning speed of 1, the connection portion 9 between the second electrodes 6 and 7 and the first electrode 2 is formed. Through the above manufacturing steps, the photoelectric conversion device of this example could be completed.

By adopting such a structure, the output end 13 of the photoelectric conversion device can be directly fixed to the substrate with a strong adhesive and has a sufficient adhesive force. Further, the connection with the electrode was achieved by Ag paste, which was sufficiently good, and it was possible to form the output end of the photoelectric conversion device without performing local heating. Further, since the output end can be provided on the back surface side of the substrate as described above, this output can be performed by the area of the photoelectric conversion device when being supplied to the outside, and the peripheral area for taking out can be reduced. I was able to.

[Embodiment 2] In this embodiment, the photoelectric conversion device has a structure as shown in FIG. This structure is an example in which the conductive portion 12 for connecting the second electrode 7 and the output end 13 on the back surface of the substrate is provided on the end surface of the substrate. Other manufacturing steps can be performed in the same manner as in Example 1, but the laser step is not necessary because the substrate is penetrated.

In order to use the end face of the substrate as the conducting portion 12, the output end 13 is adhered to the back face of the substrate so as to protrude from the substrate. By doing so, the number of steps can be further reduced while obtaining the same effect as that of the first embodiment. Further, unlike the first embodiment, since the conductive portion 12 is not limited in size, there is an advantage that the reliability for connection and the manufacturing yield can be increased.

[Embodiment 3] In this embodiment, the photoelectric conversion device has a structure as shown in FIG. This structure is an example in which the conductive portion 12 for connecting the second electrode 7 and the output end 13 on the back surface of the substrate is provided on the end surface of the substrate. Unlike the second embodiment, the conductive portion 12 is not made of the material of the second electrode 7 but of the material of the output end 13 provided on the back surface of the substrate, and the conductive portion 12 does not have to sandwich the substrate. It is a metal clamp. Other manufacturing steps can be performed in the same manner as in Example 1, but the laser step is not necessary because the substrate is penetrated.

The metallic clamp which also serves as the conducting portion 12 and the output end 13 is provided so as to be fitted in a U-shape with respect to the cross section of the photoelectric conversion device, and is more firmly fixed. Of course, an adhesive to the substrate may be provided if necessary.
Further, since it is not possible to secure sufficient electrical continuity with the second electrode 6 simply by sandwiching the substrate, the second electrode 7 (auxiliary electrode) is extended to above this clamp, and the second electrode 6 and 7 are connected. By securing the connection, we were able to realize a sufficient connection.

In the case of the configuration of this embodiment, the output can be taken out to the outside not only on the back surface of the substrate but also on the end surface of the substrate, and when such a photoelectric conversion device is incorporated into a product as an auxiliary power source. Was superior to.

The above three embodiments have been described by taking the photoelectric conversion device having a specific integrated structure as an example.
It is needless to say that the present invention can be applied to other structures as well, without being limited to this integrated structure.

[0039]

According to the configuration of the present invention, without soldering,
It was possible to provide an output end having good adhesive strength and sufficient conductivity on a flexible substrate having no heat resistance. This allows
A photoelectric conversion device that does not generate warpage or distortion of the substrate has been realized.

[Brief description of drawings]

FIG. 1 shows a schematic cross-sectional view of a photoelectric conversion device of the present invention.

FIG. 2 shows an example of a manufacturing process of a photoelectric conversion device of the present invention.

FIG. 3 illustrates an example of a manufacturing process of a photoelectric conversion device of the present invention.

FIG. 4 illustrates an example of a manufacturing process of a photoelectric conversion device of the present invention.

FIG. 5 illustrates an example of a manufacturing process of a photoelectric conversion device of the present invention.

FIG. 6 illustrates an example of a manufacturing process of a photoelectric conversion device of the present invention.

FIG. 7 is a schematic sectional view of a conventional photoelectric conversion device.

[Explanation of symbols]

 1. ． ． ． ． ． Substrate 2. ． ． ． ． ． First electrode 3. ． ． ． ． ． Semiconductor layer 6, 7. ． ． ． Second electrode 11. ． ． ． ． Through hole 12. ． ． ． ． Conducting part 13. ． ． ． ． Output end

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisato Shinohara 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation (72) Inventor Masayoshi Abe 1-13-1 Nihonbashi, Chuo-ku, Tokyo -In DC Inc.

Claims (4)

[Claims] 1. A thin film photoelectric conversion device provided on a substrate having no heat resistance, wherein an output end from which the output of the photoelectric conversion device can be taken out is a surface of the substrate on which the photoelectric conversion device is provided. A photoelectric conversion device, which is provided on a surface opposite to the surface of the photoelectric conversion device and has a conducting portion that electrically connects the electrode of the photoelectric conversion device and the output end. 2. The photoelectric conversion device according to claim 1, wherein the conductive portion is present in a conductive hole provided in the flexible substrate. 3. The photoelectric conversion device according to claim 1, wherein the conductive portion is present on an end surface of the flexible substrate. 4. A thin-film photoelectric conversion device provided on a substrate having no heat resistance, wherein an output end from which the output of the photoelectric conversion device can be taken out is a surface of the substrate on which the photoelectric conversion device is provided. And a conducting portion that is provided on the surface opposite to that for conducting the electrode of the photoelectric conversion device and the output end is the same as the material used for a part of the electrode of the photoelectric conversion device. A characteristic photoelectric conversion device.