KR101718796B1 - Solar cell using photon conversion and method for manufacturing the same - Google Patents

Abstract

A solar cell is disclosed. The solar cell includes: a transparent substrate; a first transparent electrode layer which is formed on the rear side of the transparent substrate; a light absorption layer which is formed on the rear side of the first transparent electrode layer; a second transparent electrode layer which is formed on the rear side of the light absorption layer; and a light conversion reflector which is formed on the rear side of the second transparent electrode layer. The light conversion reflector reflects incident light to the light absorption layer by changing a wavelength of the incident light. Accordingly, the present invention can improve photoelectric conversion efficiency.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic cell,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell using a photon conversion technique and a method of manufacturing the same.

Exhaustion of existing energy resources such as petroleum and coal has been predicted and interest in alternative energy to replace them is increasing. Particularly, as a part of alternative energy, a solar cell that produces electric energy from solar energy is attracting attention.

Solar cells (photovoltaic cells or solar cells) are the core elements of solar power generation that convert sunlight directly into electricity.

Specifically, when light is incident on the light absorbing layer of a solar cell, electron-hole pairs are generated. The electrons are moved to the n layer by the electric field formed at the pn junction and the holes are moved to the p layer. As a result, the electromotive force (photovoltage ). At this time, when a load is connected to the electrodes at both ends, current flows.

However, according to such a conventional solar cell, only a specific wavelength range of incident light is absorbed in the light absorbing layer to be converted into electric energy, and light in the other wavelength range is transmitted through the light absorbing layer to lower the photoelectric conversion efficiency There was a problem.

The background technology of the present application is disclosed in Korean Patent Laid-Open Publication No. 2011-0025581.

The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a solar cell with improved photoelectric conversion efficiency and a method of manufacturing the same.

It should be understood, however, that the technical scope of the embodiments of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

As a technical means for achieving the above technical object, a solar cell according to the first aspect of the present invention is a solar cell comprising: a transparent substrate; A first transparent electrode layer formed on a rear surface of the transparent substrate; A light absorbing layer formed on a rear surface of the first transparent electrode layer; A second transparent electrode layer formed on a rear surface of the light absorbing layer; And a photo-conversion reflector formed on a rear surface of the second transparent electrode layer, wherein the photo-conversion reflector changes the wavelength of light incident from the front and reflects the light to the light-absorbing layer.

According to a second aspect of the present invention, there is provided a method of manufacturing a solar cell, comprising: preparing a transparent substrate; Forming a first transparent electrode layer on a rear surface of the transparent substrate; Forming a light absorbing layer on the rear surface of the first transparent electrode layer; Forming a second transparent electrode layer on the rear surface of the light absorbing layer; And forming a photo-conversion reflector on the rear surface of the second transparent electrode layer, wherein the photo-conversion reflector changes the wavelength of light incident from the front and reflects the light onto the light-absorbing layer.

The above-described task solution is merely exemplary and should not be construed as limiting the present disclosure. In addition to the exemplary embodiments described above, there may be additional embodiments in the drawings and the detailed description of the invention.

According to the above-mentioned problem solving means, light having a wavelength that can be absorbed in the light absorbing layer among the light incident on the light absorbing layer can be absorbed by the light absorbing layer, is not absorbed into the light absorbing layer, Can be converted into light having a wavelength that can be absorbed by the light absorption layer by the light conversion reflector, and then reflected by the light absorption layer and absorbed by the light absorption layer. Accordingly, a solar cell having an improved light absorption rate of the light absorption layer and improved photoelectric conversion efficiency and a manufacturing method thereof can be realized.

1 is a schematic cross-sectional view of a solar cell according to an embodiment of the present invention;
2 is a schematic cross-sectional view of an enlarged view of a photo-conversion reflector according to an embodiment of the present invention;
3 is a schematic plan view of a photoconversion reflector according to one embodiment of the present invention as viewed from the front.
Fig. 4A is a diagram showing the condensing effect when a silver pattern is formed with mutual spacing of 850 nm by a finite-difference time-domain (FDTD) simulation.
Fig. 4B is a diagram showing the condensing effect when the silver patterns are formed with mutual spacing of 1000 nm by the FDTD simulation
FIG. 4C is a graph showing the relative light-collecting ratio of the incident light with respect to the wavelength when the silver pattern is repeatedly formed at intervals of 850 nm and 1000 nm according to the results of the FDTD simulation.
Fig. 5 is a conceptual diagram showing the first transparent electrode layer, the light absorbing layer, the second transparent electrode layer, and the like in Fig. 1 for explaining that light is condensed on the light conversion reflector by the convex lens.
Fig. 6 is a diagram showing the radius of curvature of the convex lens, the height of the convex lens, the distance between the center of the convex lens and the center of the neighboring convex lens in Fig.
FIG. 7 is a schematic plan view showing a glass substrate on which a convex lens is formed, which is viewed from the rear, in order to explain the arrangement of the convex lenses according to one embodiment of the present invention.
FIG. 8 is a graph of a haze curve according to a transparent electrode and a wavelength based on textured zinc oxide.
9 is a schematic conceptual cross-sectional view illustrating a step of preparing a transparent substrate according to an embodiment of the present invention.
10 is a schematic conceptual cross-sectional view illustrating a step of forming a convex lens on a transparent substrate according to an embodiment of the present invention.
11 is a schematic conceptual cross-sectional view illustrating a step of forming a first transparent electrode layer, a light absorption layer, and a second transparent electrode layer according to an embodiment of the present invention.
12 is a schematic conceptual cross-sectional view illustrating a step of forming a photo-conversion reflector on a transparent base material according to an embodiment of the present invention.
13 is a schematic conceptual cross-sectional view illustrating a step of forming a light conversion layer according to an embodiment of the present invention.
14 is a schematic conceptual cross-sectional view illustrating a step of forming a light conversion layer according to another embodiment of the present invention.
15 is a schematic conceptual cross-sectional view illustrating a step of forming a photo-conversion reflector on a transparent substrate having a first transparent electrode layer, a light absorption layer, and a second transparent electrode layer according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

It will be appreciated that throughout the specification it will be understood that when a member is located on another member "top", "top", "under", "bottom" But also the case where there is another member between the two members as well as the case where they are in contact with each other.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

For reference, the terms related to directions and positions (front, front, rear, rear, etc.) in the description of the embodiments of the present application are set with the direction in which the transparent substrate is disposed with respect to the light conversion layer forward. For example, referring to FIG. 1, the direction in which the transparent substrate is disposed on the basis of the light conversion layer is front, the surface facing the direction in which the transparent substrate is disposed on the light conversion layer is the front, The direction in which the layer is disposed may be rear, and the surface facing the direction in which the reflective layer is disposed with respect to the light conversion layer may be the rear surface. However, in the manufacturing and practical application of the embodiments of the present application, it is possible to arrange them in various directions such that the front surface faces upward.

The present invention relates to a solar cell and a manufacturing method thereof.

First, a solar cell according to one embodiment of the present invention (hereinafter referred to as "the present solar cell") will be described.

1 is a schematic cross-sectional view of a solar cell according to an embodiment of the present invention;

Referring to FIG. 1, the present solar cell includes a transparent substrate 11. The transparent substrate 11 is formed of a transparent material capable of transmitting light while supporting the structure described later, and may be made of a material including glass as an example. However, the material of the transparent substrate 11 is not limited thereto. As another example, a substrate made of a transparent polymer material may be used as the transparent substrate 11.

Referring to FIG. 1, the solar cell includes a first transparent electrode layer 12 formed on the rear surface of a transparent substrate 11. Illustratively, aluminum (Al) -doped tin dioxide (SnO2) can be applied as the first transparent electrode layer 12. Alternatively, zinc oxide (ZnO) doped with at least one of gallium (Ga) and aluminum (Al) may be applied as the first transparent electrode layer 12.

1, the present solar cell includes a light absorbing layer 13 formed on the rear surface of the first transparent electrode layer 12. The light absorbing layer 13 absorbs at least a part of the incident light. When light is absorbed, electron-hole pairs are formed, electrons are moved to the n-layer by the electric field, and holes are moved to the p-layer, whereby the photovoltaic power can be generated.

Referring to FIG. 1, the solar cell includes a second transparent electrode layer 14 formed on the rear surface of the light absorbing layer 13.

Illustratively, aluminum (Al) -doped tin dioxide (SnO2) can be applied as the second transparent electrode layer 14. Alternatively, zinc oxide (ZnO) doped with at least one of gallium (Ga) and aluminum (Al) may be applied as the first transparent electrode layer 14.

The light absorbing layer 13 is made of at least a part of the light incident from the front and transmitted through the transparent substrate 11 and the first transparent electrode layer 12 and the light incident from the rear side and transmitted through the second transparent electrode layer 14 At least a part of which can be absorbed.

Illustratively, the light absorbing layer 13 can absorb light having a specific range of wavelengths of incident light. For example, it can absorb light of short wavelength. The absorbed light is converted into electric power.

As will be described later in detail, the first transparent electrode layer 12 can scatter light that can be absorbed by the light absorbing layer 13 as much as possible. Illustratively, when the light absorbing layer 13 absorbs light having a short wavelength, the first transparent electrode layer 12 can scatter light with a short wavelength as much as possible.

Accordingly, the light that can be absorbed by the light absorbing layer 13 travels a longest distance in the light absorbing layer 13, and the light absorbing rate with respect to the light absorbing layer 13 can be increased.

1, the present solar cell includes a photo-conversion reflector 2 formed on the rear surface of the second transparent electrode layer 14. The photo-

The photo-conversion reflector 2 changes the wavelength of the light incident from the front and reflects it to the light absorbing layer 13.

That is, the light that has not been absorbed by the light absorbing layer 13 and has passed through the light absorbing layer 13 among the light having passed through the transparent substrate 11 is changed in wavelength by the light converting reflector 2, ). ≪ / RTI > At this time, the light conversion reflector 2 can change the wavelength of the incident light to a wavelength that the light absorption layer 13 can absorb.

As described above, light that has not been absorbed in the light absorbing layer 13 and has passed through the light absorbing layer among light incident through the transparent substrate 11 and absorbed by the light absorbing layer 13 is absorbed by the light converting reflector 2 .

As described above, light absorbed in the light absorbing layer 13 among the light incident on the light absorbing layer 13 can be converted into electricity. Therefore, in order to improve the photoelectric conversion efficiency, the light absorptivity of the light absorbing layer 13 must be improved.

According to this solar cell, light having a wavelength that can be absorbed in the light absorbing layer 13 among the light incident on the light absorbing layer 13 can be absorbed by the light absorbing layer 13, and the light absorbing layer 13 Is converted into light having a wavelength that can be absorbed by the light absorbing layer 13 by the light conversion reflector 2 and then is reflected by the light absorbing layer 13 to be incident on the light absorbing layer 13 Can be absorbed. Accordingly, the light absorptivity of the light absorbing layer 13 can be improved and the photoelectric conversion efficiency can be improved.

The first transparent electrode layer 12 is formed by the light which is not absorbed by the light absorption layer 13 and the light which is not absorbed by the light absorption layer 13 by causing the light of wavelengths not absorbed by the light absorption layer 13 to reach the light conversion reflector 2 without scattering It is possible to improve the contact ratio of the photo-conversion reflector 2 and improve the wavelength change rate of the non-absorbed light. Thus, the efficiency of the present solar cell can be maximized.

Referring to FIG. 1, the photo-conversion reflector 2 may include a photo-conversion layer 21 formed on the rear surface of the second transparent electrode layer 14. The light conversion layer 21 can change the wavelength of the incident light.

Illustratively, the photo-conversion layer 21 may be a material comprising an upconverting nano particle. Upconverting nanoparticles can convert long wavelength light into short wavelengths. Illustratively, light near the 980 nm band can be converted to light near the 550 nm band. As such upconverting nanoparticles, materials described by H. Schfer and M. Haase in Angewandte Chemie International Edition can be applied. 1, the photo-conversion reflector 2 may include a reflective layer 22 formed on the back surface of the photo-conversion layer 21. The photo- The reflective layer 22 can reflect the light whose wavelength has been converted by the light conversion layer 21 to the light absorption layer 13.

FIG. 2 is a schematic cross-sectional view of an enlarged view of a photo-conversion reflector according to one embodiment of the present invention, and FIG. 3 is a schematic plan view of a photo-conversion reflector viewed from the front according to an embodiment of the present invention. 3 (b) and 3 (c) show a silver pattern 212 and silver bump 221, respectively, in which the silver pattern 212 and the silver bump 221 are arranged one-dimensionally And silver bumps 212 are two-dimensionally arranged.

3 (b) is an embodiment in which a plurality of silver bumps 212 are arranged in a lattice pattern in a grid pattern, and FIG. 3 (c) is an embodiment in which a silver bump 212 surrounding one silver bump 212 And a plurality of silver bumps 212 are arranged so that the plurality of silver bumps 212 form a hexagonal pattern. 3 (a), 3 (b) and 3 (c), the cross section cut along the dotted line may be the cross section corresponding to FIG.

As shown in FIG. 2, a plurality of silver bumps 221 (Ag Bump) protruding in the direction toward the light conversion layer 21 may be provided on the front surface of the reflective layer 22 with a gap therebetween.

The reflective layer 22 may be a material containing silver. The silver bumps 221 may be made of a material containing silver (Ag). The bumps 221 may be formed at mutually spaced intervals.

2 and 3, a depressed depressed portion 211 may be formed on the front surface of the photo-conversion layer 21 so as to surround each of the plurality of silver bumps 221 with a predetermined gap therebetween . 2 and 3, a silver pattern 212 may be formed on the engraved portion 211. In addition,

Referring to FIG. 2, on a cross section cut across the silver bumps 221, silver patterns 212 may be formed at intervals. Referring to FIGS. 3 (b) and 3 (c), the silver pattern 212 may be a pattern continuously connected to each other. In other words, the spacing of the silver patterns 212 in the present invention may mean the distances between the silver patterns 212 appearing on the cross section as shown in FIG.

For example, silver patterns 212 may be formed with a spacing of 850 nm or less. Alternatively, the silver patterns 212 may be formed with an interval of 1000 nm or less.

FIG. 4A is a view showing a convergence effect in the case where the silver patterns 212 are formed with a mutual spacing of 850 nm, and FIG. 4B is a view in which the silver patterns 212 are formed by 1000 nm The light condensing effect in the case of being formed with mutual spacing is shown by FDTD simulation. Referring to FIGS. 4A and 4B, when the distance between the silver patterns 212 is 850 nm and 1000 nm, the light collecting effect can be confirmed, respectively.

As such, the silver patterns 212 may be formed with a mutual spacing of 850 nm or 1000 nm. However, the intervals of the silver patterns 212 are not limited thereto, and various design changes can be made in a direction to improve the photoelectric conversion efficiency.

As another example, the silver patterns 212 may be formed at mutually spaced intervals with a certain rule. For example, the silver pattern 212 may be formed such that two intervals of 850 nm and 1000 nm are alternated.

4C is a graph showing the relative light-collecting ratio of the incident light with respect to the wavelength according to the result of the FDTD simulation when the silver pattern 212 is repeatedly formed at intervals of 850 nm and 1000 nm. According to FIG. 4C, when the silver pattern 212 is repeatedly formed at intervals of 850 nm and 1000 nm, it can be confirmed that light of a wavelength of 980 nm is strongly condensed.

In addition, the silver pattern 212 may be applied to the engraved portion 211 (bottom surface of the engraved portion) by patterning or imprinting.

In summary, the light incident on the light conversion layer 21 can be condensed by the light conversion layer 21 by the plurality of intaglio portions 211 and the silver pattern 212. In other words, the plurality of engraved portions 211 is a periodic micro-optical structure for condensing the light incident on the light conversion layer 21. Thus, the wavelength conversion efficiency of light can be improved.

FIG. 5 is a conceptual view showing the first transparent electrode layer, the light absorbing layer, the second transparent electrode layer, and the like in FIG. 1 for explaining light condensed by the convex lens on the light conversion reflector, The radius of curvature of the convex lens, the height of the convex lens, the distance between the center of the convex lens and the center of the neighboring convex lens, and the like.

As shown in Figs. 1, 5 and 6, the transparent substrate 11 may include a plurality of convex lenses 111 protruding rearward from the rear surface thereof so that light transmitted therethrough is condensed.

5 and 6 together, the photoconversion reflector 2 is formed so that the entire surface of the photoconversion reflector 2 is converged by the convex lens 111 and is formed at the focus of the light that has passed through the optical absorption layer 13 11) at a predetermined interval (D).

Accordingly, the light that is not absorbed by the light absorbing layer 13 and passes through the light absorbing layer 13 can be focused on the light converting reflector 2 by the convex lens 111.

That is, in this solar cell, the light that is not absorbed by the light absorbing layer 13 and passes through the light absorbing layer 13 is primarily condensed on the light converting reflector 2 macroscopically using the convex lens 111, The light-converged light is microscopically focused on the light-converting layer 21 by using the above-described engraved portion 211, thereby maximizing the light conversion efficiency.

1 and 6, the photo-conversion reflector 2 and the second transparent electrode layer 14 (not shown) are formed so that the photo-conversion reflector 2 is formed at a predetermined interval from the second transparent electrode layer 14, A transparent filler 3 may be formed.

Further, the refractive index of the convex lens 111 may be larger than the refractive index of the transparent filler 3. Accordingly, as shown in Fig. 5, the condensing effect by the convex lens 111 can be exerted.

The preset distance D may be the focal length of the convex lens 111. [ According to this, the preset interval D can satisfy [Expression 1].

[Equation 1]

(The refractive index (n _L ) of the convex lens - the refractive index (n _B ) of the transparent filler)

6, the diameter A _L of the largest cross-section of the convex lens 111 may be 1.4 times or less the radius of curvature R of the convex lens 111. Here, the diameter (A _L ) of the largest cross-section of the convex lens 11 may mean the diameter of the portion where the converging effect of the convex lens is made. The height H _L of the convex lens 111 may be 0.3 times or less the radius of curvature R of the convex lens 111. The distance P _G between the center of the convex lens 111 and the center of the neighboring convex lens 111 may be 1.4 times or more the radius of curvature R of the convex lens 111. According to this, the bending angle? Of the transparent substrate 11 formed by the convex lens 111 as shown in Fig. 2 can be 145 degrees or more.

Generally, when a silicon thin film is formed on the surface of a bent substrate, a crack is formed in the silicon thin film formed by bending of the substrate. The abrupt surface change degrades the quality of the light absorbing layer, Can be reduced.

However, in this solar cell, the angle of bending of the transparent substrate 11 by the convex lens 111 is set to 145 deg. Or more so that the first transparent electrode layer 12, At least one of the first transparent electrode layer 12, the light absorbing layer 13 and the second transparent electrode layer 14 is cracked when the light absorbing layer 13 and the second transparent electrode layer 14 are formed. Can be prevented.

FIG. 7 is a schematic plan view showing a glass substrate on which a convex lens is formed, which is viewed from the rear, in order to explain the arrangement of the convex lenses according to one embodiment of the present invention.

 As shown in Fig. 7 (a), the center of the convex lens 111 can form a lattice pattern with the center of the neighboring convex lens 111. [

Alternatively, as shown in Fig. 7 (b), the center of each of a plurality of neighboring convex lenses 111 surrounding the convex lens 111 may have a hexagonal pattern.

7A, the light-converging area ratio of the convex lens 111 per unit area in the case where the center of the convex lens 111 forms a lattice pattern with the center of the neighboring convex lens 111, The converging area ratio of the convex lens 111 per unit area in the case where the center of each of a plurality of neighboring convex lenses 111 surrounding one convex lens 111 forms a hexagonal pattern as shown in (b) of FIG. %. ≪ / RTI >

Therefore, as shown in FIG. 7B, the convex lenses 111 are arranged so that the center of each of a plurality of neighboring convex lenses 111 surrounding one convex lens 111 is a hexagon pattern desirable.

Further, each of the plurality of convex lenses 111 may be a material including at least one of glass, oxide, and polymer.

Illustratively, the convex lens 111 may be made of the same material as the transparent substrate 11. In this case, after forming a film of the same material as that of the transparent substrate 11 on the transparent substrate 11, a convex lens shape can be realized by a method such as etching or imprinting. In this case, the convex lens 111 may be made of a material including glass.

Alternatively, the convex lens 111 may be made of a material including at least one of an oxide and a polymer. If the transparent substrate 11 is made of a material including glass and the convex lens 111 is made of a material containing at least one of oxide and polymer, the transparent substrate 11 and the convex lens 111 are made of different materials . In this case, after forming a film of a material including at least one of oxide and polymer on the transparent substrate 11, a convex lens shape can be realized by a method such as etching or imprinting.

Also, in the present solar cell, the first transparent electrode layer 12 may be textured to have a haze ratio of less than 5% when light having a wavelength of 800 nm is incident thereon.

The haze ratio indicates the degree of scattering of incident light without going straight. For reference, a transparent electrode based on textured zinc oxide and a haze curve according to wavelength are shown in Fig.

Illustratively, in the present solar cell, the film formation is performed by sputtering or LPCVD during the manufacturing process of the first transparent electrode 12, and the crystal direction is randomly formed naturally during the film formation, or after patterning Texturing can be formed through random etching. At this time, a light scattering effect occurs in the front transparent electrode by the texturing.

As described above, the light absorption rate of the light absorbing layer 13 can be increased by allowing the light incident on the light absorbing layer 13 to proceed as far as possible. Therefore, the light absorption rate can be increased by maximizing the light scattering (by increasing the haze value) in the first transparent electrode 12. Further, if the degree of light scattering becomes extremely large, the lens effect by the convex lens 111 is reduced, and the degree of light condensation can be reduced. Accordingly, referring to FIG. 8, it is preferable that the first transparent electrode layer 12 is textured so that a haze ratio of incident light of 800 nm wavelength is less than 5%.

In summary, the present solar cell generally comprises a light conversion reflector 2 (light source) that converts low-energy light (light of a long wavelength) into light of high energy (light of a short wavelength) It is possible to improve the photoelectric conversion efficiency by allowing the light absorbing layer 13 to absorb light of a wavelength that can not be absorbed by the light absorbing layer 13 and to improve the photoelectric conversion efficiency of the transparent substrate 11 including the convex lens 111, By including the photoconversion layer 21 which improves the light collection efficiency of the light to the photoconversion layer 21 macroscopically using the photoconversion layer 21 and the recessed portion 211 which is coated with the silver 212 on the rear surface, It is possible to maximize the photoelectric conversion efficiency by maximizing the light collection rate of the light to the layer 21. [

Hereinafter, a method for manufacturing a solar cell according to an embodiment of the present invention (hereinafter referred to as a "present manufacturing method") for manufacturing a solar cell will be described in the above-described embodiment of the present invention. However, the same reference numerals are used for the same or similar components as those of the solar cell according to one embodiment of the present application, and redundant descriptions will be simplified or omitted.

9 is a schematic conceptual cross-sectional view illustrating a step of preparing a transparent substrate according to an embodiment of the present invention

Referring to Fig. 9, the present manufacturing method includes a step of preparing a transparent substrate 11.

In the step of preparing the transparent substrate 11, the transparent substrate 11 may be made of a material including glass.

10 is a schematic conceptual cross-sectional view illustrating a step of forming a convex lens on a transparent substrate according to an embodiment of the present invention.

10, the step of preparing the transparent substrate 11 may include the step of forming a plurality of convex lenses 111 projecting from the rear surface of the transparent substrate 11 to the rear side.

10 (a), the convex lens 111 may be made of the same material as the transparent substrate 11. In this case, after forming a film of the same material as that of the transparent substrate 11 on the transparent substrate 11, a convex lens shape can be realized by a method such as etching or imprinting. In this case, the convex lens 111 may be made of a material including glass.

Alternatively, the convex lens 111 may be made of a material including at least one of an oxide and a polymer. In this case, referring to FIG. 10B, if the transparent substrate 11 is made of glass, the convex lens 111 may be made of a material different from the transparent substrate 11. In this case, after forming a film of a material including at least one of oxide and polymer on the transparent substrate 11, a convex lens shape can be realized by a method such as etching or imprinting.

In the step of forming the convex lens 111, the refractive index of the convex lens 111 may be larger than the refractive index of the transparent filler 3.

In addition, in the step of forming the convex lens 111, the diameter A _L of the largest cross-section of the convex lens 111 may be 1.4 times or less the radius of curvature R of the convex lens 111. Here, the diameter (A _L ) of the largest cross-section of the convex lens 11 may mean the diameter of the portion where the converging effect of the convex lens is made. The height H _L of the convex lens 111 may be 0.3 times or less the radius of curvature R of the convex lens 111. The distance P _G between the center of the convex lens 111 and the center of the neighboring convex lens 111 may be 1.4 times or more the radius of curvature R of the convex lens 111. .

The step of forming the convex lens 111 may form the convex lens 111 so that the center of the convex lens 111 forms a lattice pattern with the center of the neighboring convex lens 111. [ Alternatively, the step of forming the convex lens 111 may form the convex lens 111 so that the center of each of a plurality of neighboring convex lenses 111 surrounding the single convex lens 111 forms a hexagonal pattern .

11 is a schematic conceptual cross-sectional view illustrating a step of forming a first transparent electrode layer, a light absorption layer, and a second transparent electrode layer according to an embodiment of the present invention.

11, the manufacturing method includes the step of forming a first transparent electrode layer 12 on the rear surface of the transparent substrate 11. As shown in FIG.

The step of forming the first transparent electrode layer 12 may include forming the first transparent electrode layer 12 by texturing so that a haze ratio of incident light of 800 nm wavelength to the first transparent electrode layer 12 is less than 5% .

11, the manufacturing method includes a step of forming a light absorbing layer 13 on the rear surface of the first transparent electrode layer 12. [

11, the manufacturing method includes the step of forming a second transparent electrode layer 14 on the rear surface of the light absorbing layer 13.

12 is a schematic conceptual cross-sectional view illustrating a step of forming a photo-conversion reflector on a transparent base material according to an embodiment of the present invention.

Referring to Fig. 12, the present manufacturing method includes forming a photo-conversion reflector 2.

The photo-conversion reflector 2 changes the wavelength of the light incident from the front and reflects it to the light absorbing layer 13.

Illustratively, the step of forming the photo-conversion reflector 2 includes the step of forming the photo-conversion reflector 2 on the entire surface of the transparent base material 29, as shown in Fig.

13 (a) and 14 (a), the step of forming the photo-conversion reflector 2 on the entire surface of the transparent base material 29 includes the steps of forming a reflective layer 22). ≪ / RTI >

FIG. 13 is a schematic conceptual cross-sectional view illustrating a step of forming a light conversion layer according to an embodiment of the present invention, and FIG. 14 is a schematic cross-sectional view illustrating a step of forming a light conversion layer according to another embodiment of the present invention Fig.

More specifically, as shown in Figs. 13A and 14A, the step of forming the reflective layer 22 on the entire surface of the transparent base material 29 includes the steps of: 22). ≪ / RTI > The applied silver (22) can form the reflective layer (22).

13A and 14A, the step of forming the reflective layer 22 on the entire surface of the transparent base material 29 may be performed after the step of applying the silver 22, And forming a plurality of silver bumps 221 at an interval on the entire surface of the layer formed by the silver (22) application.

13 (b) to 14 (d) and 14 (b) to 14 (d), the step of forming the light conversion reflector 2 on the entire surface of the transparent base material 29 includes the steps of And forming a photo-conversion layer 21 on the entire surface of the substrate 22.

The step of forming the light conversion layer 21 on the entire surface of the reflective layer 22 may be performed by forming the upconverting nanoparticle 21a on the front surface of the reflective layer 22 as shown in Figure 13 (b) The method comprising the steps of:

13C, the step of forming the light conversion layer 21 on the entire surface of the reflective layer 22 may include forming a silver pattern 212 on the entire surface of the applied upconverting nanoparticle 21a, To form a second layer.

13 (d), the step of forming the light conversion layer 21 on the entire surface of the reflective layer 22 includes the step of forming the upconverting nanoparticle 21b on the entire surface of the upconverting nanoparticle 21a, And removing the applied upconverting nanoparticles on the front side of the silver pattern 212. The method of FIG. The upconverting nanoparticles 21a and 21b can form a light conversion layer. Accordingly, the light conversion layer 21 may include the engraved portion 211 and the silver pattern 212 may be formed on the lower surface of the engraved portion 211 (the rear surface of the engraved portion 211) .

In another embodiment of the present invention, the step of forming the light conversion layer 21 on the entire surface of the reflective layer 22 may be performed as follows.

The step of forming the light conversion layer 21 on the entire surface of the reflective layer 22 includes the step of applying the upconverting nanoparticle 21 to the entire surface of the reflective layer 22 as shown in Figure 14 (b) . ≪ / RTI >

14 (c), a step of forming a sacrificial layer 28 on the entire surface of the coated up-converting nanoparticle 21 and performing patterning corresponding to the engraved portion 211 . Further, as shown in FIG. 14 (c), the step of performing silver deposition corresponding to the silver pattern 212 may be performed on the entire surface of the patterned sacrificial layer 28. 14 (d), removing the silver on the sacrificial layer 28 and the sacrificial layer 28 may be included.

15 is a schematic conceptual cross-sectional view illustrating a step of forming a photo-conversion reflector on a transparent substrate having a first transparent electrode layer, a light absorption layer, and a second transparent electrode layer according to an embodiment of the present invention.

15, the first transparent electrode layer 12, the light absorbing layer 13, and the second transparent electrode layer 14 are formed so as to face the second transparent electrode layer 14 and the light conversion reflector 2, And then joining the formed transparent substrate 11 and the transparent base material 29 on which the photo-conversion reflector 2 is formed.

The step of bonding the transparent substrate 11 on which the first transparent electrode layer 12, the light absorbing layer 13 and the second transparent electrode layer 14 are formed and the transparent base material 29 on which the photo-conversion reflector 2 is formed The photo-conversion reflector 3 and the transparent substrate 11 are spaced apart from each other by a preset distance so that the lower surface of the photo-conversion reflector 3 is focused by the convex lens 111, The transparent substrate 11 on which the first transparent electrode layer 12, the light absorbing layer 13 and the second transparent electrode layer 14 are formed and the transparent base material 29 on which the photo-conversion reflector 2 is formed can be bonded.

Illustratively, the transparent substrate 11 on which the first transparent electrode layer 12, the light absorbing layer 13 and the second transparent electrode layer 14 are formed, and the transparent base material 29 on which the photo-conversion reflector 2 is formed The bonding step may combine the second transparent electrode layer 14 and the photo-conversion reflector 3 using the transparent filler 3 as shown in Fig.

The step of combining the transparent substrate 11 on which the one transparent electrode layer 12, the light absorbing layer 13 and the second transparent electrode layer 14 are formed and the transparent base material 29 on which the photo-conversion reflector 2 is formed Thereafter, the transparent base material 29 can be removed.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

11: transparent substrate 111: convex lens
12: first transparent electrode layer 13: light absorbing layer
14: second transparent electrode layer 2: photo-conversion reflector
21: light conversion layer 211: concave portion
212: silver 22: reflective layer
221: silver bump 3: transparent filler
28: sacrificial layer 29: transparent base material

Claims (27)

In solar cells,
A transparent substrate;
A first transparent electrode layer formed on a rear surface of the transparent substrate;
A light absorbing layer formed on a rear surface of the first transparent electrode layer;
A second transparent electrode layer formed on a rear surface of the light absorbing layer; And
And a photo-conversion reflector formed on a rear surface of the second transparent electrode layer,
Wherein the photo-conversion reflector includes a light conversion layer formed on a rear surface of the second transparent electrode layer and a reflective layer formed on a rear surface of the light conversion layer,
A plurality of silver bumps protruding in a direction toward the light conversion layer are provided on the front surface of the reflective layer with a gap therebetween,
Wherein a concave depressed portion is formed on the front surface of the light conversion layer so as to surround each of the plurality of silver bumps and spaced apart from each of the plurality of silver bumps by a predetermined distance,
A silver pattern is formed on the engraved portion,
Wherein a wavelength of light incident from the front is changed by the light conversion reflector and is reflected by the light absorption layer. The method according to claim 1,
Wherein the light converted by the light conversion reflector is insufficient in the light absorbing layer of the light incident through the transparent substrate and the light having passed through the light absorbing layer is absorbed by the light absorbing layer. delete delete delete The method according to claim 1,
Wherein the silver pattern is recessed rearward from the front surface of the light conversion layer. The method according to claim 1,
And the distance between the plurality of silver patterns is 850 nm or 1000 nm. The method according to claim 1,
Wherein the light conversion layer is a material comprising upconverting nano particles. The method according to claim 1,
Wherein the reflective layer is made of a material containing silver. The method according to claim 1,
Wherein the transparent substrate includes a plurality of convex lenses protruding rearward from a rear surface thereof so as to condense the light transmitted therethrough,
Wherein the light conversion reflector is formed at a predetermined interval from the transparent substrate so that the front surface of the light conversion reflector is converged by the convex lens and is formed at a focus of light passing through the light absorption layer. 11. The method of claim 10,
And a transparent filler material formed between the photo-conversion reflector and the second transparent electrode layer such that the photo-conversion reflector is formed at the predetermined interval from the second transparent electrode layer. 12. The method of claim 11,
Wherein the refractive index of the convex lens is larger than the refractive index of the transparent filler. 11. The method of claim 10,
Wherein the diameter of the largest cross section of the convex lens is 1.4 times or less the radius of curvature of the convex lens, the height of the convex lens is 0.3 times or less the radius of curvature of the convex lens, Is 1.4 times or more the radius of curvature of the convex lens. 11. The method of claim 10,
And the center of the convex lens forms a lattice pattern with the center of the adjacent convex lens. 11. The method of claim 10,
Wherein a center of each of a plurality of adjacent convex lenses surrounding the convex lens is a hexagonal pattern. 11. The method of claim 10,
Wherein the transparent substrate is made of glass,
Wherein each of the plurality of convex lenses is made of a material containing at least one of glass, oxide, and polymer. The method according to claim 1,
Wherein the first transparent electrode layer comprises:
And texturing (surface unevenness) so that a haze ratio at incidence of 800 nm wavelength light is less than 5%. A method of manufacturing a solar cell,
Preparing a transparent substrate;
Forming a first transparent electrode layer on a rear surface of the transparent substrate;
Forming a light absorbing layer on the rear surface of the first transparent electrode layer;
Forming a second transparent electrode layer on the rear surface of the light absorbing layer; And
And forming a photo-conversion reflector on the rear surface of the second transparent electrode layer,
In the step of forming a photo-conversion reflector on the rear surface of the second transparent electrode layer, the photo-conversion reflector is formed on the rear surface of the second transparent electrode layer and on the rear surface of the light- And a plurality of silver bumps protruding in a direction toward the light conversion layer are provided on the front surface of the reflective layer so as to be spaced apart from each other, Wherein each of the plurality of silver bumps is formed with a depressed depressed portion spaced apart from each of the silver bumps by a predetermined distance so as to surround each of the plurality of silver bumps,
Wherein the wavelength of light incident from the front is changed by the light conversion reflector and is reflected by the light absorption layer. 19. The method of claim 18,
Wherein forming the photo-conversion reflector on the backside of the second transparent electrode layer comprises:
Forming the photo-conversion reflector on the transparent base material; And
The transparent substrate on which the first transparent electrode layer, the light absorbing layer, and the second transparent electrode layer are formed, and the transparent base material on which the photo-conversion reflector is formed are combined so that the second transparent electrode layer and the photo- Wherein the method comprises the steps of: 20. The method of claim 19,
The step of forming the photo-conversion reflector on the transparent base material may include:
Forming the reflective layer on the entire surface of the transparent base material; And
And forming the light conversion layer on the entire surface of the reflective layer. 21. The method of claim 20,
Wherein forming the reflective layer comprises:
Silver is applied to the entire surface of the transparent base material,
Wherein the plurality of silver bumps are formed on the entire surface of the layer formed by the application by mutual spacing. 22. The method of claim 21,
In the step of forming the light conversion layer,
Wherein the concave portion and the silver pattern are formed on a front surface of the light conversion layer. 23. The method of claim 22,
Wherein forming the light conversion layer comprises:
Applying upconverting nanoparticles to the front surface of the reflective layer;
Forming a silver pattern on the entire surface of the applied upconverting nanoparticle; And
Further comprising the step of applying an upconverting nanoparticle to the entire surface of the upconverting nanoparticle having the silver pattern formed thereon and removing the upconverting nanoparticle coated on the entire surface of the silver pattern. 23. The method of claim 22,
Wherein forming the light conversion layer comprises:
Applying an upconverting nanoparticle to the front surface of the reflective layer;
Forming a sacrificial layer on the entire surface of the coated up-converting nanoparticle and performing patterning corresponding to the engraved portion;
Performing silver deposition corresponding to the silver pattern on the entire surface of the patterned sacrificial layer;
And removing the sacrificial layer and silver deposited on the sacrificial layer. 20. The method of claim 19,
The step of preparing the transparent substrate may include:
And forming a plurality of convex lenses protruding rearward from the rear surface of the transparent substrate,
The step of bonding the transparent base material on which the first transparent electrode layer, the light absorption layer, and the second transparent electrode layer are formed, and the transparent base material on which the photo-conversion reflector is formed,
The light conversion reflector and the transparent substrate are spaced apart from each other by a predetermined interval so that the lower surface of the light conversion reflector is formed at a focus of the light focused by the convex lens so that the first transparent electrode layer, Wherein the transparent substrate on which the transparent electrode layer is formed is combined with the transparent base material on which the photo-conversion reflector is formed. 20. The method of claim 19,
The step of bonding the transparent base material on which the first transparent electrode layer, the light absorption layer, and the second transparent electrode layer are formed, and the transparent base material on which the photo-conversion reflector is formed,
And combining the second transparent electrode layer and the photo-conversion reflector using a transparent filler. 19. The method of claim 18,
Wherein forming the first transparent electrode layer comprises:
And texturing the first transparent electrode layer so that a haze ratio at the time of incident light of 800 nm wavelength into the first transparent electrode layer is less than 5%.

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