KR20110086335A

KR20110086335A - Thin film type solar cell and method for manufacturing the same

Info

Publication number: KR20110086335A
Application number: KR1020100006011A
Authority: KR
Inventors: 김태훈
Original assignee: 주성엔지니어링(주)
Priority date: 2010-01-22
Filing date: 2010-01-22
Publication date: 2011-07-28
Also published as: KR101676364B1

Abstract

The present invention, a substrate; A light scattering film formed on the substrate and including a bead and a binder to fix the bead; A front electrode layer formed on the light scattering layer and having a first separator; A semiconductor layer formed on the front electrode layer and having a contact portion and a second separator; And a back electrode layer formed on the semiconductor layer and electrically connected to the front electrode layer through the contact part and provided with the second separation part, wherein the light scattering layer corresponds to the first separation part. A thin film type solar cell, and a method of manufacturing the same, characterized in that at least one of the openings, the second opening portion corresponding to the contact portion, and the third opening portion corresponding to the second separation portion is provided.
According to the present invention, by forming a light scattering film between the substrate and the front electrode layer can be variously refracted sunlight can lengthen the path of sunlight in the semiconductor layer, the light scattering film acts as a barrier during the front electrode layer deposition process The impurities contained in the substrate may be prevented from moving to the front electrode layer, and the light scattering layer may be patterned so that an opening is formed in the light scattering layer, thereby forming a first or second separation unit for separation between unit cells. The problem that the path of the laser beam is changed during the process or the process of forming the contact portion for the inter-electrode connection can be solved.

Description

Thin film type solar cell and method for manufacturing same

The present invention relates to a solar cell, and more particularly to a thin film solar cell.

Solar cells are devices that convert light energy into electrical energy using the properties of semiconductors.

The structure and principle of the solar cell will be briefly described. The solar cell has a PN junction structure in which a P (positive) type semiconductor and a N (negative) type semiconductor are bonded to each other. Holes and electrons are generated in the semiconductor by the energy of the incident solar light. At this time, the holes (+) are moved toward the P-type semiconductor by the electric field generated in the PN junction. Negative (-) is the principle that the electric potential is generated by moving toward the N-type semiconductor to generate power.

Such a solar cell can be classified into a substrate type solar cell and a thin film solar cell.

The substrate type solar cell is a solar cell manufactured by using a semiconductor material such as silicon as a substrate, and the thin film type solar cell is a solar cell manufactured by forming a semiconductor in the form of a thin film on a substrate such as glass.

Substrate-type solar cells, although somewhat superior in efficiency compared to thin-film solar cells, there is a limitation in minimizing the thickness in the process and there is a disadvantage that the manufacturing cost is increased because of the use of expensive semiconductor substrates.

Although thin-film solar cells are somewhat less efficient than substrate-type solar cells, they can be manufactured in a thin thickness and inexpensive materials can be used to reduce manufacturing costs, making them suitable for mass production.

Hereinafter, a thin film solar cell according to the related art will be described with reference to the accompanying drawings.

1 is a schematic perspective view of a thin film solar cell according to the related art.

As can be seen in FIG. 1, the thin film solar cell according to the related art includes a substrate 10, a front electrode layer 20, a semiconductor layer 30, a transparent conductive layer 40, and a back electrode layer 50.

The front electrode layer 20 includes a first separator 25 for cell separation, and is formed to be divided into unit cells by the first separator 25.

The semiconductor layer 30 and the transparent conductive layer 40 are formed to include a contact portion 35 for connection between electrodes and a second separation portion 55 for cell separation.

The back electrode layer 50 is electrically connected to the front electrode layer 20 through the contact portion 35 and is formed to be divided into unit cells by the second separation unit 55.

However, such a conventional thin film solar cell has the following problems.

First, in order to improve the efficiency of the solar cell, it is necessary to increase the generation rate of holes and electrons in the semiconductor layer 30 by lengthening a path through which the sunlight passes through the semiconductor layer 30. . However, the conventional thin film solar cell has a problem in that the path of the solar light is long formed in the semiconductor layer 30 and thus there is a problem in that battery efficiency cannot be obtained as desired.

Second, in general, the substrate 10 uses glass, and alkali ions are contained in the glass, and the alkali ions move to the front electrode layer 20 in the process of performing a high temperature deposition process. As a result, there is a problem that the efficiency of the solar cell is lowered.

The present invention has been devised to solve the conventional problems as described above, the present invention is to provide a thin-film solar cell and a method of manufacturing the same that can increase the efficiency of the solar cell by increasing the path of sunlight in the semiconductor layer. The purpose.

Another object of the present invention is to provide a thin film solar cell and a method of manufacturing the same, which can increase the efficiency of a solar cell by preventing the alkali ions contained in the substrate from moving to the front electrode layer.

The present invention, in order to achieve the above object; A light scattering film formed on the substrate and including a bead and a binder to fix the bead; A front electrode layer formed on the light scattering layer and having a first separator; A semiconductor layer formed on the front electrode layer and having a contact portion and a second separator; And a back electrode layer formed on the semiconductor layer and electrically connected to the front electrode layer through the contact part and provided with the second separation part, wherein the light scattering layer corresponds to the first separation part. At least one of an opening, a second opening corresponding to the contact portion, and a third opening corresponding to the second separation portion is provided.

The opening may include the first opening, the second opening, and the third opening. In this case, the semiconductor layer is formed in the first opening, and the front electrode layer is in the second opening and the third opening. It may be formed.

The light scattering layer may further include a fourth opening in a region corresponding to the outermost region of the substrate.

The light scattering layer may have a refractive index different from that of the substrate or the front electrode layer.

The beads and the binder constituting the light scattering film may have different refractive indices.

The beads may be a combination of a plurality of beads having different refractive indices.

The bead consists of a core part and a skin part surrounding the core part, the core part and the skin part may be made of a material having different refractive indices. In this case, the core part may be made of air, and the core part or skin part It may be composed of a plurality of material layers having different refractive indices from each other.

The light scattering film may have a surface having an uneven structure.

The front electrode layer may have a concave-convex structure on its surface.

The semiconductor layer may include a first semiconductor layer and a second semiconductor layer formed with a buffer layer therebetween.

A transparent conductive layer may be further formed between the semiconductor layer and the back electrode layer.

The present invention also provides a light scattering film comprising a bead and a binder for fixing the bead, having at least one of a first opening portion, a second opening portion, and a third opening portion on a substrate; Forming a front electrode layer having a first separator on the light scattering film; Forming a semiconductor layer having a contact portion on the front electrode layer; And forming a back electrode layer on the semiconductor layer, the back electrode layer electrically connected to the front electrode layer through the contact part, and having a second separation part.

The step of forming the front electrode layer having the first separator comprises: forming a front electrode layer on the entire surface of the substrate including the light scattering film; And forming a first separator in the front electrode layer region corresponding to the first opening.

The step of forming a semiconductor layer including the contact portion may include forming a semiconductor layer on an entire surface of the substrate including the front electrode layer; And forming a contact portion in the semiconductor layer region corresponding to the second opening.

The process of forming a back electrode layer having the second separator may include forming a back electrode layer on the entire surface of the substrate including the semiconductor layer; And forming a second separator in the back electrode layer region corresponding to the third opening.

The step of forming a semiconductor layer having the contact portion and the step of forming a back electrode layer having the second separator include: forming a semiconductor layer on the entire surface of the substrate including the front electrode layer; Forming a contact portion in the semiconductor layer region corresponding to the second opening and forming a second separator in the semiconductor layer region corresponding to the third opening; And patterning the back electrode layer to include the second separator using a printing method.

The light scattering film may be formed to further include a fourth opening in a region corresponding to the outermost region of the substrate. In this case, after the process of forming the back electrode layer, the outermost region corresponding to the fourth opening may be formed. The method may further include forming isolation parts on the front electrode layer, the semiconductor layer, the transparent conductive layer, and the rear electrode layer.

The process of forming the light scattering film may be performed by using a printing method, a sol-gel method, a dip coating method, or a spin coating method using a paste while applying a mask covering the opening, in this case, forming the light scattering film The process may further perform a firing process after film formation in order to enhance the bonding force between the substrate and the light scattering film.

The light scattering layer may be formed such that the refractive index of the substrate or the front electrode layer is different from each other.

The beads and the binder may have different refractive indices.

The beads may use a combination of a plurality of beads having different refractive indices.

The bead consists of a core part and a skin part surrounding the core part, and the core part and the skin part may use materials having different refractive indices. In this case, the core part may be made of air, and the core part or skin part It may be composed of a plurality of material layers having different refractive indices from each other.

The light scattering film may have a surface having an uneven structure.

The forming of the front electrode layer may include forming a front electrode layer having a concave-convex structure through a deposition process, or forming a front electrode layer having a uniform surface through a deposition process, and then etching the surface through an etching process. It can be made in the process of forming.

The method may further include forming a transparent conductive layer between the semiconductor layer and the back electrode layer.

According to the present invention as described above has the following effects.

According to the present invention, by forming a light scattering film between the substrate and the front electrode layer, the sunlight can be variously refracted to lengthen the path of sunlight in the semiconductor layer. Therefore, the efficiency of the solar cell is improved.

In addition, by appropriately changing the material and pattern of the beads and the binder constituting the light scattering film can be easily adjusted the refractive pattern of the solar light it is possible to optimize the efficiency of the solar cell.

In addition, in the present invention, since the light scattering film is formed between the substrate and the front electrode layer, the light scattering film acts as a barrier in the process of depositing the front electrode layer so that impurities contained in the substrate move to the front electrode layer. It is blocked, there is an effect that the degradation of the efficiency of the solar cell is prevented.

In addition, the present invention by forming the light scattering film patterned so that the opening is provided in the light scattering film, the laser beam during the process of forming the first or second separation for separation between unit cells or the process of forming a contact for inter-electrode connection The problem of changing the path of can be solved.

1 is a schematic perspective view of a thin film solar cell according to the related art.
2 is a schematic perspective view of a thin film solar cell according to an embodiment of the present invention.
3A-3C are cross-sectional views of beads according to various embodiments of the present invention.
4A to 4G are perspective views illustrating a manufacturing process of a thin film solar cell according to an embodiment of the present invention.
5A to 5F are perspective views illustrating a manufacturing process of a thin film solar cell according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

2 is a schematic perspective view of a thin film solar cell according to an embodiment of the present invention.

As can be seen in Figure 2, the thin-film solar cell according to an embodiment of the present invention, the substrate 100, the light scattering film 200, the front electrode layer 300, the semiconductor layer 400, the transparent conductive layer 500, and the back It comprises an electrode layer 600.

The substrate 100 may be made of glass or transparent plastic.

The light scattering layer 200 is formed on the substrate 100 and includes a bead 220 and a binder 240. The light scattering layer 200 scatters the sunlight passing through the substrate 100 at various angles and prevents impurities contained in the substrate 100 from moving to the front electrode layer 300. do.

First, the light scattering film 200 will be described for scattering the sunlight passing through the substrate 100 at various angles as follows.

The light scattering layer 200 includes a bead 220 and a binder 240. The binder 240 is mainly in contact with the substrate 100 and the front electrode layer 300. In this case, when a material having a refractive index different from that of the substrate 100 and the front electrode layer 300 is used as a material constituting the binder 240, sunlight transmitted through the substrate 100 may be formed. Since the light is refracted while passing through the binder 240 and the light transmitted through the binder 240 is refracted again while passing through the front electrode layer 300, the light incident on the substrate 100 is eventually reduced. As the light is refracted at various angles, the light is incident on the semiconductor layer 400 so that the path of sunlight in the semiconductor layer 400 is long.

In some cases, the bead 220 may come into contact with the substrate 100 and the front electrode layer 300. In this case, the substrate 100 and the substrate may be formed of a material constituting the bead 220. When the material constituting the front electrode layer 300 and a material having a different refractive index are used, the solar light incident on the substrate 100 is refracted at various angles by the same mechanism as described above and is incident on the semiconductor layer 400. The path of sunlight in the semiconductor layer 400 is long.

In general, since the refractive index of the glass constituting the substrate 100 is about 1.52, and the refractive index of the front electrode layer 300 is about 1.9 to 2.0, the range of the refractive index of the substrate 100 and the front electrode layer 300 is In consideration of this, the material of the bead 220 or the binder 240 may be selected. Examples of the beads 220 may include silicon oxide (eg, SiO _2). Oxides containing silicon elements such as silicon), transition metal oxides (for example, oxides containing transition metal elements such as TiO ₂ and CeO ₂ ), and the like, and examples of the binder 240 include silicates and the like. However, it is not necessarily limited thereto.

In addition, when the beads 220 and the binder 240 constituting the light scattering film 200 are made of materials having different refractive indices from each other, sunlight may be variously refracted in the light scattering film 200. That is, when the beads 220 are made of a material having a different refractive index than that of the binder 240, the sunlight transmitted through the beads 220 is refracted while passing through the binder 240, and the binder ( Since the sunlight transmitted through the 240 is refracted while passing through the bead 220, the sunlight may be variously refracted.

In addition, instead of forming the beads 220 with the same material, when a plurality of beads having different refractive indices are used in combination with each other, sunlight may be refracted at various angles while passing through the beads 220 having different values from each other. .

In addition, the bead 220 may be composed of a core part and a skin part, so that sunlight may be refracted at various angles while passing through one bead 220.

3A-3C are cross-sectional views of beads 220 in accordance with various embodiments of the present invention.

As can be seen in Figure 3a, the bead 220 is composed of a core portion 222 and a skin portion 224 surrounding the core portion 222, the material of the core portion 222 to the skin portion ( By using a material having a refractive index different from that of the material of 224, sunlight is refracted when passing through the core part 222 after passing through the skin part 224, and after passing through the core part 222. When passing through the skin unit 224 can be made to refract again.

As can be seen in Figure 3b, the core portion 222 is made of air so that the same effect can be obtained using the hollow bead 220 consisting of only the skin portion 224.

As shown in FIG. 3C, the core part 222 may be composed of a plurality of material layers 222a and 222b having different refractive indices, and the skin part 224 may have a plurality of material layers 224a having different refractive indices. , 224b).

In addition, by changing the cross-section of the bead 220 in a variety of forms, such as circular, elliptical may be variously changed the angle of refraction of sunlight.

In addition, as can be seen in the enlarged view of FIG. 2, by forming the light scattering film 200 to have a concave-convex structure, the refractive angle of solar light may be variously changed.

Next, when the light scattering film 200 prevents the impurities contained in the substrate 100 from moving to the front electrode layer 300, the light scattering film 200 is the substrate 100 and the Since it is formed between the front electrode layer 300, during the deposition process of the front electrode layer 300, the light scattering film 200, in particular the binder 240 constituting the light scattering film 200 acts as a barrier (barrier) Impurities contained in the substrate 100 are blocked from moving to the front electrode layer 300.

The light scattering film 200 including the bead 220 and the binder 240 is patterned on the substrate 100 so that the openings 210, 230, and 250 are provided.

The openings 210, 230, and 250 provided in the light scattering layer 200 include a first opening 210, a second opening 230, and a third opening 250, each opening of the front electrode layer. The pattern forming process of the 300, the semiconductor layer 400, the transparent conductive layer 500, or the back electrode layer 600 may be easily performed.

That is, in order to form the pattern of the front electrode layer 300, the semiconductor layer 400, the transparent conductive layer 500, or the back electrode layer 600, so-called laser scribing that irradiates a laser beam from the lower side of the substrate 100. Through the process, the first separation part 310, the contact part 430, or the second separation part 650 should be formed, in which case a laser beam passes through the beads 220 included in the light scattering film 200. In this case, the path of the laser beam may be changed, such that the first separation unit 310, the contact unit 430, or the second separation unit 650 may be formed in an undesirable shape. Therefore, in the present invention, the openings 210, 230, and 250 are formed in the light scattering film 200 region corresponding to the region to which the laser beam is irradiated, thereby preventing the path of the laser beam from being changed.

In particular, the light scattering layer 200 may include a first opening 210 corresponding to the first separation unit 310, a second opening 230 corresponding to the contact unit 430, and the second separation unit ( And a third opening 250 corresponding to the 650. The light scattering film 200 according to the present invention necessarily includes both the first opening 210, the second opening 230, and the third opening 250. It is not limited only to the case provided, but may be provided with only one or two openings.

In addition, in the modularization process of the thin-film solar cell, the housing of a predetermined type is connected to the thin-film solar cell. In this case, an isolation part is formed in the outermost region of the thin-film solar cell in order to prevent a short between the housing and the thin-film solar cell. The isolation unit may remove a predetermined region of the front electrode layer 300, the semiconductor layer 400, the transparent conductive layer 500, and the rear electrode layer 600 formed in the outermost region of the thin film solar cell by a laser beam. It can be formed through the process. Therefore, a fourth opening (not shown) may be further formed in the light scattering film 200 to correspond to the isolation portion formed in the outermost region.

The front electrode layer 300 is formed on the light scattering layer 200, and has a first separator 310 for cell separation. That is, the front electrode layer 300 is divided by unit cells by the first separator 310. In addition, the front electrode layer 300 is also formed in the second opening 230 and the third opening 250 provided in the light scattering film 200.

Since the front electrode layer 300 is formed on a surface where sunlight is incident, the front electrode layer 300 is doped with a material containing ZnO (eg, ZnO: B, ZnO: Al) or a hydrogen element, which is doped with a material containing a ZnO or Group III element. It may be formed using a transparent conductive material such as ZnO (eg, ZnO: H), SnO ₂ , SnO ₂ : F, or Indium Tin Oxide (ITO).

The surface of the front electrode layer 300 may be formed with a concave-convex structure. When the surface of the front electrode layer 300 is formed with a concave-convex structure, the incident solar light may be scattered in various ways in the semiconductor layer 400. It can improve the absorption of sunlight.

However, if the concave-convex structure of the front electrode layer 300 is formed too large, defects may occur in the semiconductor layer 400 and the transparent conductive layer 500 formed on the front electrode layer 300. This can fall. In the present invention, since the scattering effect of sunlight can be sufficiently obtained by the light scattering film 200, it is not necessary to form an uneven structure largely on the surface of the front electrode layer 300, thus the front electrode layer 300 The uneven structure of the surface is preferably adjusted so small that defects do not occur in the semiconductor layer 400 and the transparent conductive layer 500.

On the other hand, the surface of the front electrode layer 300 may not be formed in an uneven structure.

That is, as one method for forming the surface of the front electrode layer 300 in the concave-convex structure, the front electrode layer 300 having the surface of the concave-convex structure is deposited by controlling the deposition process conditions of the front electrode layer 300. There is a method of forming, this method may not be easy to obtain the desired uneven pattern because it is not easy to control the deposition process conditions, the semiconductor formed on the front electrode layer 300 when the uneven pattern is not desired Defects may occur in the layer 400 and the transparent conductive layer 500.

In addition, as another method for forming the surface of the front electrode layer 300 in a concave-convex structure, the front electrode layer 300 having a flat surface is deposited once, and then the surface of the front electrode layer 300 is formed in a concave-convex pattern by a chemical etching process. There is a method of forming, which is complicated by the addition of a chemical etching process, the environmental problems due to chemicals and the cost of treatment can be caused.

Therefore, in the present invention, since the light is refracted at various angles through the light scattering film 200, it is not necessary to form a separate uneven structure on the surface of the front electrode layer 300.

The semiconductor layer 400 is formed on the front electrode layer 300, and when the surface of the front electrode layer 300 is formed in an uneven structure, the surface of the semiconductor layer 400 may also be formed in an uneven structure.

The semiconductor layer 400 includes a contact portion 430 and a second separation portion 650. The contact part 430 serves as a path for electrically connecting the front electrode layer 300 and the back electrode layer 600, and the second separator 650 connects the back electrode layer 600 to each unit cell. To distinguish.

The semiconductor layer 400 is also formed in the first opening 210 provided in the light scattering layer 200 through the first separation unit 310 provided in the front electrode layer 300.

The semiconductor layer 400 may have a PIN structure in which a P (positive) type semiconductor layer, an I (intrinsic) type semiconductor layer, and an N (negative) type semiconductor layer are sequentially stacked. The N-type semiconductor layer refers to a semiconductor layer doped with an N-type doping material (eg, group 5 elemental materials such as antimony (Sb), arsenic (As), phosphorus (P), etc.), and the I-type semiconductor layer is an intrinsic semiconductor. The P-type semiconductor layer refers to a semiconductor layer doped with a P-type doping material (eg, a group 3 element material such as boron (B), gallium (Ga), indium (In), etc.).

As described above, when the semiconductor layer 400 has a PIN structure, the I-type semiconductor layer is depleted by the P-type semiconductor layer and the N-type semiconductor layer to generate an electric field therein, and is generated by sunlight. As the holes and electrons are drift by the electric field, holes are collected to the front electrode layer 300 through the P-type semiconductor layer and electrons are collected to the back electrode layer 600 through the N-type semiconductor layer. On the other hand, when the semiconductor layer 400 is formed in a PIN structure, it is preferable to form a P-type semiconductor layer on the front electrode 300 and then to form an I-type semiconductor layer and an N-type semiconductor layer. In general, since the drift mobility of the holes is low due to the drift mobility of the electrons, the P-type semiconductor layer is formed close to the light receiving surface in order to maximize the collection efficiency due to incident light.

Meanwhile, an N-type or P-type semiconductor layer having a thickness thinner than that of the N-type or P-type semiconductor layer may be formed instead of the I-type semiconductor layer, or instead of the N-type or P-type semiconductor layer instead of the I-type semiconductor layer. An N-type or P-type semiconductor layer having a low doping concentration may be formed.

In addition, although the silicon layer compound may be used as the semiconductor layer 400, a compound such as CIGS (CuInGaSe 2) may be used.

On the other hand, as can be seen in the enlarged view of Figure 2, the semiconductor layer 400 is the first semiconductor layer 401, the buffer layer 402, and the second semiconductor layer 403 are sequentially stacked so-called tandem (tandem) It may be formed into a structure.

The first semiconductor layer 401 and the second semiconductor layer 403 may both be formed in a PIN structure in which a P-type semiconductor layer, an I-type semiconductor layer, and an N-type semiconductor layer are sequentially stacked.

The first semiconductor layer 401 may be made of an amorphous semiconductor material having a PIN structure, and the second semiconductor layer 403 may be made of a microcrystalline semiconductor material having a PIN structure.

Since the amorphous semiconductor material absorbs light of short wavelength well and the microcrystalline semiconductor material absorbs light of long wavelength well, light absorption efficiency may be enhanced when the amorphous semiconductor material and the microcrystalline semiconductor material are combined. . However, the present invention is not limited thereto, and various modifications such as an amorphous semiconductor / germanium, a microcrystalline semiconductor material, a crystalline semiconductor material, etc. may be used as the first semiconductor layer 401, and the amorphous semiconductor may be used as the second semiconductor layer 403. Various modifications such as materials, amorphous semiconductors / germanium, and crystalline semiconductor materials can be used.

The buffer layer 402 serves to facilitate the movement of holes and electrons through tunnel junctions between the first semiconductor layer 401 and the second semiconductor layer 403, and includes ZnO and Group 3 elements. ZnO doped with a material (eg ZnO: B, ZnO: Al), ZnO doped with a material containing a hydrogen element (eg ZnO: H), SnO ₂ , SnO ₂ : F, or Indium Tin Oxide (ITO) It may be formed of a transparent material such as.

In addition, the semiconductor layer 400 may be formed in a triple structure including a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, and a buffer layer formed between each semiconductor layer, in addition to a tandem structure. May be

The transparent conductive layer 500 is formed between the semiconductor layer 400 and the back electrode layer 600, but may be omitted in some cases.

The transparent conductive layer 500 is ZnO (eg, ZnO: B, ZnO: Al) doped with a material containing a ZnO, Group 3 element, ZnO (eg, ZnO: H) doped with a material containing a hydrogen element, It may be made of a transparent conductive material such as SnO ₂ , SnO ₂ : F, or ITO (Indium Tin Oxide), and the surface of the transparent conductive layer 500 may be formed of an uneven structure.

The transparent conductive layer 500 may include a contact portion 430 and a second separation portion 650 similarly to the semiconductor layer 400, but is not limited thereto. It may be formed in the contact portion 430.

The back electrode layer 600 is formed on the transparent conductive layer 500 and is electrically connected to the front electrode layer 300 through the contact portion 430.

The back electrode layer 600 includes a second separator 650 for cell separation. That is, the back electrode layer 600 is divided by unit cells by the second separator 650.

The back electrode layer 600 may be formed of a metal such as Ag, Al, Ag + Mo, Ag + Ni, Ag + Cu.

4A to 4G are perspective views illustrating a manufacturing process of a thin film solar cell according to an embodiment of the present invention.

First, as shown in FIG. 4A, a light scattering layer 200 including a bead 220 and a binder 240 fixing the beads 220 is formed on the substrate 100.

Glass or transparent plastic may be used as the substrate 100.

The light scattering layer 200 is formed in a pattern to include at least one of the first opening 210, the second opening 230, and the third opening 250. In addition, the light scattering layer 200 may be patterned to further include a fourth opening in a region corresponding to the outermost region of the substrate 100.

The light scattering layer 200 may be uniformly distributed on the binder 240 to prepare a paste, and then may be formed using a printing method using such a paste, or a sol-gel (Sol- It may be formed using a gel method, a dip coating method, or a spin coating method. In this case, by applying a mask covering the openings 210, 230, and 250, the openings ( The light scattering film 200 having the 210, 230, and 250 may be patterned.

In forming the light scattering film 200, after forming the film in the same manner as described above, the bonding force between the substrate 100 and the light scattering film 200 by additionally performing an infrared firing process or a low temperature / high temperature firing process It is desirable to promote

The light scattering film 200 can be formed in the concave-convex structure as can be seen in the enlarged view, in this case, the printing method, the sol-gel method, dip coating After performing the method or the spin coating method (Spin Coating), the surface of the film may be formed into a concave-convex structure by physical contact.

Since the bead 220 and the binder 240 constituting the light scattering film 200 are the same as described above, a detailed description thereof will be omitted.

Next, as can be seen in Figure 4b, the front electrode layer 300 is formed on the front surface of the substrate including the light scattering film 200.

The front electrode layer 300 may include ZnO (eg, ZnO: B, ZnO: Al) doped with a material containing a ZnO, group III element, or ZnO (eg, ZnO: H) doped with a material containing a hydrogen element. It may be laminated using a transparent conductive material such as SnO ₂ , SnO ₂ : F, or ITO (Indium Tin Oxide), and the surface thereof may be formed with an uneven structure.

As such a method of forming the front electrode layer 300 having a concave-convex structure, the front electrode layer having the concave-convex structure may be directly controlled by appropriately adjusting the deposition conditions during a deposition process such as a metal organic chemical vapor deposition (MOCVD) process. There is a method of forming or forming a front electrode layer of a uniform surface through a deposition process such as a sputtering process and then forming the surface into an uneven structure through an etching process. The etching process may include an etching process using photolithography, anisotropic etching using a chemical solution, or an etching process using mechanical scribing.

As described above, the uneven structure of the surface of the front electrode 300 is preferably adjusted so small that defects do not occur in the semiconductor layer and the transparent conductive layer to be formed in a later process.

On the other hand, the surface of the front electrode 300 may not be formed in a concave-convex structure, in this case, the front electrode layer 300 can be laminated using a common sputtering method.

Next, as shown in FIG. 4C, a first separator 310 is formed in the front electrode layer 300.

The first separating part 310 is formed through a so-called laser scribing process of irradiating a laser beam from the lower side of the substrate 100, and in particular, the first opening 210 provided in the light scattering film 200. It is formed in the region of the front electrode layer 300 corresponding to the.

As such, since the first separator 310 is formed in the region of the front electrode layer 300 corresponding to the first opening 210, a laser beam is applied to the bead 220 provided in the light scattering layer 200. As a result, the path is not changed, and thus, the front electrode layer 300 can be formed in a desired pattern.

Next, as shown in FIG. 4D, the semiconductor layer 400 and the transparent conductive layer 500 are sequentially formed on the entire surface of the substrate including the front electrode layer 300.

The semiconductor layer 400 may be formed in a PIN structure in which a silicon-based amorphous semiconductor material is sequentially stacked with a P-type semiconductor layer, an I-type semiconductor layer, and an N-type semiconductor layer by using a plasma CVD method or the like.

In addition, as can be seen from the enlarged view, the semiconductor layer 400 is formed by stacking the first semiconductor layer 401, the buffer layer 402, and the second semiconductor layer 403 in order to form a so-called tandem structure. You may.

Detailed description of the material constituting the semiconductor layer 400 is the same as described above and will be omitted.

The transparent conductive layer 500 is ZnO (eg, ZnO: B, ZnO: Al) doped with a material containing a ZnO, Group 3 element, ZnO (eg, ZnO: H) doped with a material containing a hydrogen element, A transparent conductive material such as SnO ₂ , SnO ₂ : F, or ITO (Indium Tin Oxide) may be formed by laminating by sputtering or metal organic chemical vapor deposition (MOCVD). However, the process of forming the transparent conductive layer 500 may be omitted.

Next, as shown in FIG. 4E, a contact portion 430 is formed in the semiconductor layer 400 and the transparent conductive layer 500.

The contact portion 430 is formed through a so-called laser scribing process of irradiating a laser beam from the lower side of the substrate 100, and in particular, corresponds to the second opening 230 provided in the light scattering layer 200. In the semiconductor layer 400 and the transparent conductive layer 500.

As such, since the contact portion 430 is formed in the semiconductor layer 400 and the transparent conductive layer 500 corresponding to the second opening 230, a laser beam is provided in the light scattering layer 200. The path of the semiconductor layer 400 and the transparent conductive layer 500 can be formed in a desired pattern by the reference numeral 220.

Next, as can be seen in Figure 4f, to form a back electrode layer 600 on the front surface of the substrate including the transparent conductive layer (500).

The back electrode layer 600 may be formed of a metal such as Ag, Al, Ag + Mo, Ag + Ni, Ag + Cu using a sputtering method or a printing method.

Next, as can be seen in Figure 4g, the second separator 650 is formed on the back electrode layer 600. Then, the back electrode layer 600 is electrically connected to the front electrode layer 300 through the contact portion 430 and is divided by unit cells by the second separator 650.

The second separator 650 is formed through a so-called laser scribing process of irradiating a laser beam from the lower side of the substrate 100, and in particular, the third opening 250 provided in the light scattering layer 200. It is formed in the region of the back electrode layer 600 corresponding to the.

As such, since the second separator 650 is formed in the region of the back electrode layer 600 corresponding to the third opening 250, a laser beam is applied to the bead 220 provided in the light scattering layer 200. As a result, the path is not changed, and thus, the back electrode layer 600 can be formed in a desired pattern.

Although not shown, after the process of forming the second separator 650 of FIG. 4G, a process of forming an isolation part in the outermost region of the substrate 100 may be further performed. The isolation part is formed through a so-called laser scribing process of irradiating a laser beam from the lower side of the substrate 100, and particularly, in an area corresponding to a fourth opening (not shown) provided in the light scattering film 200. Form. More specifically, the isolation part is formed on the front electrode layer 200, the semiconductor layer 400, the transparent conductive layer 500, and the rear electrode layer 600 in the outermost region corresponding to the fourth opening.

5A to 5F are perspective views illustrating a manufacturing process of a thin film solar cell according to another embodiment of the present invention. In the following, repeated description of the same configuration as in the above-described embodiment will be omitted.

First, as shown in FIG. 5A, the light scattering layer 200 including the beads 220 and the binder 240 fixing the beads 220 is formed on the substrate 100.

Next, as can be seen in Figure 5b, the front electrode layer 300 is formed on the front surface of the substrate including the light scattering film 200.

The front electrode layer 300 may have a concave-convex structure or may not have a concave-convex structure.

Next, as shown in FIG. 5C, a first separator 310 is formed in the front electrode layer 300.

The first separator 310 is formed in a region of the front electrode layer 300 corresponding to the first opening 210 provided in the light scattering layer 200 through a laser scribing process.

Next, as shown in FIG. 5D, the semiconductor layer 400 and the transparent conductive layer 500 are sequentially formed on the entire surface of the substrate including the front electrode layer 300.

Next, as shown in FIG. 5E, the contact portion 430 and the second separation portion 650 are formed in the semiconductor layer 400 and the transparent conductive layer 500.

The contact portion 430 is formed in a region of the semiconductor layer 400 and the transparent conductive layer 500 corresponding to the second opening 230 provided in the light scattering layer 200 through a laser scribing process.

The second separator 650 is formed in the semiconductor layer 400 and the transparent conductive layer 500 corresponding to the third opening 250 provided in the light scattering layer 200 through a laser scribing process. .

Next, as can be seen in Figure 5f, the back electrode layer 600 is patterned.

The back electrode layer 600 is electrically connected to the front electrode layer 300 through the contact portion 430 and is formed in a pattern so as to be divided into unit cells by the second separator 650. The pattern formation of may be performed using various printing methods.

That is, the back electrode layer 600 may be screen printed, inkjet printed, or gravure printed using a metal paste such as Ag, Al, Ag + Mo, Ag + Ni, Ag + Cu, or the like. (gravure printing, gravure offset printing, reverse offset printing, flexo printing, or microcontact printing can be used to form patterns in one process have.

Although not shown, after the pattern forming process of the back electrode layer 600 according to FIG. 5F, a process of forming an isolation part in the outermost region of the substrate 100 may be additionally performed. As described above, the isolation part includes a front electrode layer 200 of a region corresponding to a fourth opening (not shown) provided in the light scattering layer 200, more specifically, an outermost region corresponding to the fourth opening. The semiconductor layer 400 is formed on the transparent conductive layer 500 and the back electrode layer 600.

100: substrate 200: light scattering film
210: first opening 230: second opening
250: third opening 220: bead
240: binder 300: front electrode layer
310: first separator 400: semiconductor layer
401: first semiconductor layer 402: buffer layer
403: second semiconductor layer 430: contact portion
500: transparent conductive layer 600: rear electrode layer
650: second separator

Claims

Board;
A light scattering film formed on the substrate and including a bead and a binder to fix the bead;
A front electrode layer formed on the light scattering layer and having a first separator;
A semiconductor layer formed on the front electrode layer and having a contact portion and a second separator; And
Is formed on the semiconductor layer, and is electrically connected to the front electrode layer through the contact portion and comprises a rear electrode layer provided with the second separation portion,
The light-scattering film has at least one of a first opening corresponding to the first separation part, a second opening corresponding to the contact part, and a third opening corresponding to the second separation part. battery.

The method of claim 1,
The opening includes the first opening, the second opening, and the third opening,
The semiconductor layer is formed in the first opening, and the front electrode layer is formed in the second opening and the third opening, characterized in that the thin-film solar cell.

The method of claim 1,
The light scattering film is a thin-film solar cell further comprises a fourth opening in a region corresponding to the outermost region of the substrate.

The method of claim 1,
The light scattering film is a thin film type solar cell, characterized in that the refractive index is different from the substrate or the front electrode layer.

The method of claim 1,
Thin film solar cell, characterized in that the beads and the binder constituting the light scattering film is different from each other.

The method of claim 1,
The bead is thin film type solar cell, characterized in that consisting of a plurality of beads having a different refractive index.

The method of claim 1,
The bead is made of a core portion and a skin portion surrounding the core portion, wherein the core portion and the skin portion is a thin film solar cell, characterized in that made of a material having a different refractive index.

The method of claim 7, wherein
The core part is a thin film solar cell, characterized in that made of air.

The method of claim 7, wherein
The core part or the skin part is a thin film solar cell, characterized in that composed of a plurality of material layers having different refractive indices.

The method of claim 1,
The light-scattering film is a thin film solar cell, characterized in that the surface is formed of an uneven structure.

The method of claim 1,
The front electrode layer is a thin film solar cell, characterized in that the surface is formed of an uneven structure.

The method of claim 1,
The semiconductor layer is a thin-film solar cell comprising a first semiconductor layer and a second semiconductor layer formed with a buffer layer therebetween.

The method of claim 1,
Thin film solar cell, characterized in that the transparent conductive layer is further formed between the semiconductor layer and the back electrode layer.

Forming a light scattering film on the substrate, the light scattering film comprising a bead and a binder to fix the bead, having at least one of a first opening, a second opening, and a third opening;
Forming a front electrode layer having a first separator on the light scattering film;
Forming a semiconductor layer having a contact portion on the front electrode layer; And
And forming a rear electrode layer on the semiconductor layer, the back electrode layer being electrically connected to the front electrode layer through the contact part and having a second separation part.

The method of claim 14,
Forming the front electrode layer having the first separation unit,
Forming a front electrode layer on the entire surface of the substrate including the light scattering film; And
And forming a first separator in the front electrode layer region corresponding to the first opening.

The method of claim 14,
The step of forming a semiconductor layer including the contact portion,
Forming a semiconductor layer on an entire surface of the substrate including the front electrode layer; And
And forming a contact portion in the semiconductor layer region corresponding to the second opening.

The method of claim 14,
Forming the back electrode layer having the second separator,
Forming a rear electrode layer on the front surface of the substrate including the semiconductor layer; And
And forming a second separator in the back electrode layer region corresponding to the third opening.

The method of claim 14,
The step of forming a semiconductor layer having the contact portion and the step of forming a back electrode layer having the second separation portion,
Forming a semiconductor layer on an entire surface of the substrate including the front electrode layer;
Forming a contact portion in the semiconductor layer region corresponding to the second opening and forming a second separator in the semiconductor layer region corresponding to the third opening; And
A method of manufacturing a thin film solar cell, comprising the step of forming a pattern on the back electrode layer to have the second separator using a printing method.

The method of claim 14,
The light scattering film is formed to further include a fourth opening in a region corresponding to the outermost region of the substrate,
After the forming of the back electrode layer, the thin film solar cell further comprises the step of forming an isolation portion in the front electrode layer, the semiconductor layer, the transparent conductive layer and the rear electrode layer in the outermost region corresponding to the fourth opening. Manufacturing method.

The method of claim 14,
The process of forming the light scattering film is a thin film solar cell manufacturing method characterized in that performed by using a printing method, a sol-gel method, a dip coating method, or a spin coating method using a paste while applying a mask covering the opening.

The method of claim 20,
The forming of the light scattering film is a method of manufacturing a thin-film solar cell, characterized in that to perform a further firing process after the film is formed in order to enhance the bonding force between the substrate and the light scattering film.

The method of claim 14,
The light scattering film is a method of manufacturing a thin film solar cell, characterized in that formed on the substrate or the front electrode layer and the refractive index is different from each other.

The method of claim 14,
The bead and the binder is a method of manufacturing a thin film solar cell, characterized in that the refractive index is different from each other.

The method of claim 14,
The bead is a method of manufacturing a thin film solar cell, characterized in that using a combination of a plurality of beads having different refractive index.

The method of claim 14,
The bead comprises a core portion and a skin portion surrounding the core portion, wherein the core portion and the skin portion manufacturing method of a thin film solar cell, characterized in that using a material having a different refractive index.

The method of claim 25,
The core part manufacturing method of the thin-film solar cell, characterized in that made of air.

The method of claim 25,
The core part or skin part is a thin film solar cell manufacturing method, characterized in that composed of a plurality of material layers different in refractive index.

The method of claim 14,
The light scattering film is a method of manufacturing a thin-film solar cell, characterized in that the surface is formed in an uneven structure.

The method of claim 14,
The forming of the front electrode layer may include forming a front electrode layer having a concave-convex structure through a deposition process, or forming a front electrode layer having a uniform surface through a deposition process, and then etching the surface through an etching process. Method for producing a thin-film solar cell, characterized in that consisting of a step of forming a.

The method of claim 14,
The method of manufacturing a thin film solar cell further comprising the step of forming a transparent conductive layer between the semiconductor layer and the back electrode layer.

The method of claim 14,
The semiconductor layer is a method of manufacturing a thin film solar cell comprising a first semiconductor layer and a second semiconductor layer formed with a buffer layer interposed therebetween.