KR20110119392A - Solar cell - Google Patents

Abstract

PURPOSE: A solar cell is provided to improve the photoelectric efficiency of a solar cell by including a transparent conductive layer with a network structure of a metal nano line. CONSTITUTION: A first transparent electrode(113) is formed on a first insulation substrate(110). A first P/I/N junction semiconductor layer(120) is formed on the upper side of the first transparent electrode. The first P/I/N junction semiconductor layer is composed of an n type impurity semiconductor material layer, a hydrogenated silicon layer, and a p type impurity semiconductor material layer. The first transparent conductive layer includes a networked metal nano wire. A second transparent electrode(140) is formed on the upper side of the first transparent conductive layer.

Description

Solar cell {Solar cell}

The present invention relates to a solar cell, and more particularly to a solar cell capable of increasing the solar collection rate.

In general, a solar cell is a semiconductor device that converts solar energy into electrical energy, and has a junction type of a p-type semiconductor and an n-type semiconductor. The basic structure is the same as that of a diode.

That is, most ordinary solar cells have a structure of a p-n junction semiconductor layer composed of a p-type semiconductor layer and an n-type semiconductor layer between electrodes facing each other.

At this time, a requirement that such solar electricity has for photovoltaic energy conversion is basically that electrons must be asymmetrically present in the p-n junction semiconductor layer structure. That is, in the p-n junction semiconductor layer, the n-type semiconductor layer has a large electron density and a small hole density, and the p-type semiconductor layer should be made to have a small electron density and a large hole density. Therefore, in the pn junction semiconductor layer, which is a junction of a p-type semiconductor and an n-type semiconductor in a thermal equilibrium state, an imbalance of electric charges occurs due to diffusion due to a concentration gradient of a carrier. field) is formed so that no further carrier diffusion occurs. At this time, when light having an energy greater than band gap energy, which is an energy difference between a conduction band and a valence band of a material forming the same, is irradiated inside the pn junction semiconductor layer, The energized electrons are excited at the conduction band in the conduction band, and the electrons excited at the conduction band are free to move, and holes are generated at the electron exit band. The generated free electrons and holes are called excess carriers, and the excess carriers are diffused by concentration differences in the conduction band or the valence band. At this time, the excess carriers, that is, electrons excited in the p-type semiconductor and holes made in the n-type semiconductor are defined as respective minority carriers, and carriers in the p-type or n-type semiconductor before the conventional junction (ie, p Holes of type n and electrons of type n) are defined as majority carriers. At this time, the plurality of carriers are interrupted by the flow due to the energy barrier (energy barrier) due to the electric field, the electron of the p-type minority carrier can move toward the n-type. The diffusion of the minority carriers causes a potential drop in the p-n junction semiconductor layer, and when the electromotive force generated at the anode terminal of the p-n junction semiconductor layer is connected to an external circuit, it acts as a battery.

On the other hand, the solar cell having the above-described functions to form a transparent electrode and a rear electrode on the outside of the pn junction semiconductor layer to use the electromotive force generated through the internal action as described above, from the external light source In order to efficiently receive light into the pn junction semiconductor layer, irregularities are formed on the surface of the transparent electrode.

1 is a cross-sectional view of a conventional general solar cell.

As shown in the drawing, the conventional solar cell is formed of a conductive material having excellent reflectivity on the first substrate 10, and a first electrode 13 serving as an electrode and a reflecting plate is formed, and the first electrode ( 13) a first P / I composed of a first n-type impurity layer 15 doped with n-type impurities, a hydrogenated amorphous silicon layer 17, and a first p-type impurity layer 19 doped with p-type impurities The / N junction semiconductor layer 20 is formed, and the second P / I / N junction semiconductor layer 28 and the third P / have the same configuration as the first P / I / N junction semiconductor layer 20. An I / N junction semiconductor layer 36 is provided, and a transparent conductive oxide is formed on the third p-type impurity layer 34 doped with the p-type impurity of the third P / I / N junction semiconductor layer 36. The second electrode 40 is formed to protect the first to third P / I / N junction semiconductor layers 20, 28, and 36 above the second electrode 40. The transparent insulating substrate 2, there is provided (50).

At this time, each hydrogenated amorphous silicon layer 17, 24, 32 positioned between the impurity-doped impurity layers in the first to third P / I / N junction semiconductor layers 20, 28, 36 has its energy. In addition to hydrogenated silicon, a predetermined amount of germanium (Ge) may be added or finely crystallized in addition to hydrogenated silicon to form a microcrystalline silicon layer. In this case, the energy bandgap of the third junction semiconductor layer 36 has the largest value, and the first to third junction semiconductor layers 20, 28, and 36 are gradually reduced toward the lower portion thereof. ) Is placed.

Thus, the first to third junction semiconductor layers 20 (p (p-type impurity layer) / i (pure amorphous silicon layer) / n (n-type impurity layer) bonded between the first and second electrodes (13, 40) The reason why the layers 28 and 36 are stacked is to improve the light absorption in each of the junction semiconductor layers 20, 28, and 36, and the multiple junctions of the junction semiconductor layers 20, 28, and 36 having different energy band gaps. By absorbing light having different wavelength bands in each of the junction semiconductor layers 20, 28, and 36, the photoelectric energy efficiency can be improved compared to a solar cell having a single PN junction semiconductor layer.

However, as described above, the conventional solar cell 1 having a structure having a multi-junction structure of the P / I / N junction semiconductor layers 20, 28, and 36 still has a light energy conversion efficiency of 20% or less. And there is much room for improving the photoelectric conversion efficiency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and proposes a structure that can further improve the absorption of light at the boundary of each semiconductor layer having a P / I / N configuration by absorbing the external light more effectively, The purpose is to improve the efficiency.

A solar cell according to an embodiment of the present invention for achieving the above object, the first insulating substrate; A first transparent electrode formed on the first insulating substrate; A first P / I / N junction semiconductor layer formed on the first transparent electrode and sequentially formed of an n-type impurity semiconductor material layer, a hydrogenated silicon layer, and a p-type impurity semiconductor material layer; A first transparent conductive layer having a networked structure of metal nanowires formed on the first P / I / N junction semiconductor layer; It includes a second transparent electrode formed on the first transparent conductive layer.

In this case, between the first transparent electrode and the first P / I / N junction semiconductor layer, second and third P / I / N junctions having the same configuration as the first first P / I / N junction semiconductor layer The semiconductor layer may be formed, and in this case, the first, 2, 3 P / I / N junction semiconductor layer is characterized in that the energy bandgap in order to have a large order, in this case the first P / I / The first I layer of the N junction semiconductor layer is made of hydrogenated microcrystalline silicon, and the second I layer of the second P / I / N junction semiconductor layer is made of hydrogenated amorphous silicon mixed with germanium (Ge), The third I layer of the third P / I / N junction semiconductor layer is made of mixed hydrogenated amorphous silicon.

In addition, a second transparent conductive layer having a networked structure of metal nanowires may be formed between the second P / I / N junction semiconductor layer and the third P / I / N junction semiconductor layer. A third transparent conductive layer having a networked structure of metal nanowires may be formed between the 1 P / I / N junction semiconductor layer and the second P / I / N junction semiconductor layer. In this case, the metal nanowires in the first, second, third transparent conductive layer is characterized in that made of silver (Ag) or gold (Au), the first, second, third transparent conductive layer has a light transmittance of 80 % To 99%, and sheet resistance is characterized by 1 kW / sq to 100 kW / sq.

In addition, a reflective plate may be provided between the first insulating substrate and the first transparent electrode or on an outer surface of the first insulating substrate.

In addition, the first and second transparent electrodes are each made of one of GZO (gallium-zinc-oxide), AZO (aluminum-zinc-oxide), ZnO (zinc-oxide), SnO (tin-oxide). .

In addition, surfaces of the first transparent electrode, the first P / I / N junction semiconductor layer, and the first transparent conductive layer each have an uneven structure, or the first transparent electrode and the first, second, The surface of each of the 3 P / I / N junction semiconductor layers and the first, second, and third transparent conductive layers has an uneven structure.

In addition, the metal nanowires are characterized in that the shape of the cylinder, triangular prism, square pillar.

As described above, the solar cell according to the present invention further induces scattering of external light between the p-type impurity layer and the n-type impurity or between the second electrode made of the p-type impurity layer and the transparent conductive oxide, and implements a surface plasmon resonance effect. By providing a transparent conductive layer having a network structure of a metal nanowire, the light of each wavelength band can be better absorbed into each P / I / N junction semiconductor layer, thereby improving the photoelectric efficiency of the solar cell.

Furthermore, since the surface of each P / I / N junction semiconductor layer has a concave-convex structure, there is an effect of improving the scattering characteristics upon incidence of external light, thereby improving the photoelectric efficiency of the solar cell.

1 is a cross-sectional view showing a laminated structure of a conventional solar cell.
2 is a cross-sectional view showing a laminated structure of a solar cell according to the present invention.
3 is a plan view of a part of the transparent conductive layer in which the metal nanowires used in the present invention form a network structure.
Figures 4a to 4c is a view showing the shape of the metal nanowires used in the present invention.
5A and 5B are graphs showing scattering distribution characteristics of wavelengths of a transparent conductive layer having a networking structure of silver (Ag) and gold (Au) nanowires, respectively.
FIG. 6 is a graph of measurement of light absorption for each wavelength of external light when silver (Ag) nanowires are not formed as a comparative example and when forming a transparent conductive layer having a networked structure. FIG.

Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings.

2 is a cross-sectional view showing a laminated structure of a solar cell according to the present invention.

As shown, the solar cell according to the present invention is provided with a reflecting plate 111 made of a conductive material such as aluminum (Al) or silver (Ag) having excellent reflectivity on the first substrate 110. The transparent conductive oxide is formed on the reflective plate 111, for example, any one of GZO (gallium-zinc-oxide), AZO (aluminum-zinc-oxide), ZnO (zinc-oxide), SnO (tin-oxide). 1 The transparent electrode 113 is formed. In this case, the reflective plate 111 may be omitted when the first substrate 110 itself is made of a metal material having excellent reflectivity, or the reflective plate 111 may be formed on the outer surface of the first substrate 110. It may be. In this case, the first transparent electrode 113 is formed on the inner surface of the first substrate 110.

Next, a first N-type impurity layer (hereinafter referred to as N layer) 113 and a first hydrogenated pure amorphous silicon layer (hereinafter referred to as I layer) doped with n-type impurities on the first transparent electrode 113. A first P layer / I layer / N layer (hereinafter referred to as P / I / N) composed of 117 and a first P-type impurity layer (hereinafter referred to as P layer) 119 doped with p-type impurities The layer 120 is formed, and the second P / I / N junction semiconductor layer 128 having a similar configuration to that of the first P / I / N junction semiconductor layer 120 in a stacked form on top thereof and The third P / I / N junction semiconductor layer 136 is provided. In this case, the difference between the first, second, and third P / I / N junction semiconductor layers 120, 128, and 136 is that the first P / I / N junction semiconductor layer 120 has a different energy band gap. The first I layer 117 is made of hydrogenated fine crystalline silicon (μc-Si: H), and the second I layer 124 in the second P / I / N junction semiconductor layer 128 It is made of hydrogenated amorphous silicon (a-SiGe: H) mixed with germanium (Ge), and the third I layer 132 in the third P / I / N junction semiconductor layer 136 is hydrogenated amorphous silicon (a -Si: H). By such a configuration, the first, second, and third P / I / N junction semiconductor layers 120, 128, and 136 having different energy band gaps are formed, thereby improving absorption of external light. Since the energy bandgap of hydrogenated amorphous silicon is the largest, and has the energy bandgap size in the order of hydrogenated amorphous silicon mixed with germanium and microcrystallized silicon, external light having a relatively short wavelength (300 nm to 700 nm) is relatively large. Absorbed mainly by the third I layer 132 having an energy band gap, and external light having a relatively long wavelength (600 nm to 1100 nm) is mainly absorbed by the first I layer 117 having a relatively small energy band gap, and As a result, external light having an intermediate wavelength (400 nm to 900 nm) is mainly absorbed by the second I layer 124.

In addition, a transparent conductive oxide such as GZO (gallium-zinc-oxide), AZO (aluminum-zinc-oxide), ZnO (zinc-oxide), SnO is formed on the third P / I / N junction semiconductor layer 135. The second transparent electrode 140 is formed of any one of (tin-oxide), and the second transparent electrode 140 and the first to third P / I / N junctions are formed on the second transparent electrode 140. A transparent second insulating substrate 150 is provided to protect the semiconductor layers 120, 128, and 136. In this case, although not shown in the drawing, an adhesive layer (not shown) is interposed between the second insulating substrate 150 and the second transparent electrode 140 to allow the second insulating substrate 150 and the second transparent electrode ( 140 is in a bonded state.

At this time, the most characteristic of the solar cell 100 according to the present invention, between the second transparent electrode 140 and the third P / I / N junction semiconductor layer 136, and the third P / I / N junction Between the semiconductor layer 136 and the second P / I / N junction semiconductor layer 128 and between the second P / I / N junction semiconductor layer 128 and the first P / I / N junction semiconductor layer 120 The transparency, that is, the transmittance of light is 80% to 99%, and the sheet resistance is about 1 Pa to about 100 Pa, and is shown in FIG. As described above, the transparent conductive layers 141, 143, and 145 of the plurality of metal nanowires 147 are networked. In this case, the metal nanowire 147 is preferably silver (Ag) or gold (Au), and the shape of the metal nanowire 147 is shown in FIGS. 4A to 4C (the shape of the metal nanowire used in the present invention). As shown in the figure), the cross section has a circular rod, a triangular prism, and a quadrangular prism.

Meanwhile, the metal nanowires 147 between the P / I / N junction semiconductor layers 120, 128, and 136 and between the second transparent electrode 140 and the third P / I / N junction semiconductor layer 136. Forming the networked transparent conductive layers 141, 143, and 145 improves the scattering of light incident on the solar cell 100 and induces surface plasmon resonance to induce each of the I layers 117, 124, This is to increase the amount of light absorbed by 132 and finally improve photoelectric efficiency.

Surface plasmon resonance is a group of conduction band electrons that propagate along the interface between a metal with a negative dielectric function (ε '<0) and a medium with a positive dielectric constant (ε'> 0). It causes vibrations, which are manifested as surface plasmon waves. When the phases of the transverse magnetic wave parallel to the metal surface and the surface plasmon wave propagating along the metal surface coincide with each other, resonance occurs. In this case, the energy of the incident wave is absorbed by the metal thin film. The reflected wave disappears, and the electric field distribution in the direction perpendicular to the metal surface is amplified exponentially at the metal surface and rapidly decreases toward the metal thin film. As the metal thickness increases, total reflection occurs. This surface plasmon resonance occurs as a result of the interaction between light and nanoscale noble metals.

Therefore, in the present invention, the transparent conductive patterns 141, 143, and 145, which form the networked metal nanowires 147, are interposed between the P / I / N junction semiconductor layers 120, 128, and 136 and the third layer. It is provided between the P / I / N junction semiconductor layer 136 and the second transparent electrode 140 so that surface plasmon resonance occurs between the P / I / N junction semiconductor layers 120, 128, and 136. Light can be scattered without reflection to increase the length of the optical path as well as improve quantum efficiency characteristics. In particular, since light is captured on the surface of the metal nanowire 147 even though it is a very short time, the light collection rate of the light absorption layer (usually I layer) located below is improved.

Furthermore, the transparent conductive layers 141, 143, and 145 having the networking structure of the metal nanowires are a minority carrier in the junction between the P layer and the N layer due to the high transmittance and low resistivity of the metal nanowires 147. By lowering the recombination rate of the electrons and holes in the separated state forming a has a further effect to improve the photoelectric efficiency.

Meanwhile, referring to FIGS. 5A and 5B (a graph showing scattering distribution characteristics for each wavelength of a transparent conductive layer having a networking structure of silver (Ag) and gold (Au) nanowires), the metal nanowires are a kind of metal material forming the same. As can be seen that the scattering wavelength range is different.

That is, it can be seen that the transparent conductive layer having a silver (Ag) nanowire networking structure (see FIG. 5A) mainly scatters light in the wavelength band of 350 nm to 450 nm, and the transparent conductive layer having a gold nanowire networking structure. (See FIG. 5B) Light mainly scatters in the wavelength range of 450 nm to 650 nm.

 Therefore, in order to most effectively implement scattering characteristics of light by reflecting this fact, in the embodiment of the present invention, the third transparent conductive layer 145 having the silver (Ag) nanowire networking structure may be formed of the second transparent electrode ( The second transparent conductive layer 143 is formed between the third P layer 134 of the third P / I / N junction semiconductor layer 136 and has the gold (Au) nanowire networking structure. It is characterized in that it is formed between the third N layer 130 and the second P layer 126.

However, the transparent conductive layer having the networking structure of the silver (Ag) and gold (Au) nanowires 147 must be the second transparent electrode 140 and the third P / I / N junction semiconductor as described above. It may not be formed only between the third P layer 134 of the layer 136 or between the third N layer 130 and the second P layer 126, but may be formed by reversing its position. Obviously, it may be formed between the P layer 119 and the second N layer 122.

FIG. 6 is a graph illustrating wavelengths of light absorption of external light when silver (Ag) nanowires are not formed as a comparative example and when forming a transparent conductive layer having a networked structure.

As shown, the comparative example in which the transparent conductive layer having the silver (Ag) nanowire networked structure is not formed shows that the light absorption is about 0.3% on average, but the silver (Ag) nanowire networked structure is shown. In the embodiment of the present invention having a transparent conductive layer having a light scattering property in a specific wavelength band is increased, especially absorbance in the wavelength band region between 350nm to 500nm is found to have a value of about 0.5% or more and 2.0% Can be.

On the other hand, the solar cell 100 according to the present invention, in addition to the formation of the metal nanowire networked transparent conductive layer in order to further expand the scattering of the external light incident therein, each P layer (119, 126, 134), I layer (117, 124, 132) and the surfaces of the N layers (115, 122, 130) are formed so as to have a convex uneven structure.

Thus, the surface of each of the P layers 119, 126, 134, I layers 117, 124, 132, and the N layers 115, 122, 130 has an uneven structure, so that light incident on the surface of the conventional flat surface is uneven. Compared to a solar cell (see FIG. 1) having a P layer, an I layer, and an N layer having the same, it is possible to prevent total reflection upon incidence of light and increase light scattering by expanding light scattering.

Hereinafter, a method of manufacturing a solar cell having the above-described configuration will be described with reference to FIG. 2 briefly.

First, a metal material having excellent reflectivity, for example, aluminum (Al) or silver (Ag), is deposited on the first insulating substrate 110 to form a reflector 111 serving as a reflective electrode. Thereafter, a transparent conductive oxide, for example, GZO (gallium-zinc-oxide), AZO (aluminum-zinc-oxide), ZnO (zinc-oxide) is formed on the upper surface of the reflective plate 111 or the inner surface of the first insulating substrate 110. ) Or SnO (tin-oxide) is deposited on the entire surface through a sputter device (not shown) to form the first transparent electrode 113 having a flat surface.

Next, in the first insulating substrate 110 on which the first transparent electrode 113 is formed, the first transparent electrode 113 is irradiated with a laser beam on a surface of the first transparent electrode 113 by using a laser device (not shown). By melting a predetermined thickness from the surface of the transparent electrode 113 and causing it to solidify naturally, crystallization proceeds to a predetermined thickness of the surface. Since the transparent conductive oxide has a property of crystallizing during melting and solidification, crystallization proceeds by the laser beam irradiation described above.

Next, dipping of the second insulating substrate 110 irradiated with a laser beam on the first transparent electrode 113 in a bath (not shown) containing an etchant reacting with the transparent conductive oxide is performed. Alternatively, irregularities are formed on the surface of the first transparent electrode 113 by performing an etching process such as spraying the etching solution on the surface of the first transparent electrode 113.

In this case, the first transparent electrode 113 exposed to the laser beam is not completely etched by appropriately adjusting the exposure time to the etchant, and part of the surface is etched and part of the surface is not etched. Convex concavities and convexities are formed in the.

Such selective etching is possible by the laser beam irradiation, wherein the first transparent electrode 113 whose predetermined thickness has been crystallized is formed at a boundary between the crystallized grain (not shown) and the grain (not shown). This is because the etching rate of is different, and faster etching is performed at the boundary portion of the grain (not shown).

Accordingly, irregularities are formed on the surface of the first transparent electrode 113 by the selective etching naturally occurring after the laser beam irradiation as described above.

Next, the first transparent electrode 113 is irradiated with a laser beam (not shown) to a region to be removed using a laser device (not shown) with respect to the first transparent electrode 113 having irregularities on the surface thereof. Pattern it.

In this case, the laser irradiation for the crystallization and the laser irradiation for the patterning may be a crystallization process or a patterning process by varying the power density, that is, by changing the laser energy irradiated per unit area. When the laser having a high energy density is irradiated, the transparent conductive oxide is completely melted and vaporized to be removed.

On the other hand, as the laser beam is irradiated and the portion irradiated with the laser beam is removed, the first transparent electrode 113 having the uneven surface thereof is separated into a plurality of parts, and thus, is uniformly sized on the first insulating substrate 110. It forms a spaced apart cell unit of. In this case, when the solar cell 100 is formed to be a single cell, the patterning process of the first transparent electrode 113 may be omitted.

Next, a first N layer 115 is formed by depositing a semiconductor material including n-type impurities on the entire surface of the first transparent electrode 113 patterned for each cell and having irregularities on the surface thereof. 1 form a hydrogenated amorphous silicon layer (not shown) over the N layer 115, and a laser beam having a low energy density, that is, an energy density at which no melting of the hydrogenated amorphous silicon layer (not shown) occurs. Irradiation or crystallization through solid state crystallization, for example, heat treatment or alternating magnetic field crystallization using an alternating magnetic field crystallization (AMFC) device is performed to form a first I layer 117 of hydrogenated fine crystalline silicon. .

Thereafter, the first N layer 115 and the first I layer are formed by depositing a semiconductor material including p-type impurities on the first I layer 117 of the hydrogenated microcrystalline silicon to form a first P layer 119. A first P / I / N junction semiconductor layer 120 composed of 117 and a first P layer 119 is formed.

On the other hand, the n-type, p-type semiconductor material and the amorphous silicon are all deposited through the chemical vapor deposition equipment reflects the surface state of the first transparent electrode 113 in terms of the deposition characteristics is that the surface is all concave-convex structure It is characteristic.

Next, by depositing the n-type impurity semiconductor material and the germanium-mixed amorphous silicon and p-type impurity semiconductor material on the first P / I / N junction semiconductor layer 120 in succession, the second N of each surface forming an uneven structure A second P / I / N junction semiconductor layer 128 composed of a layer 122, a second I layer 124, and a P layer 126 is formed.

Next, a slit-coated metal nanowire dispersion solution in which metal nanowires made of gold (Au) or silver (Ag) is dispersed on the second P / I / N junction semiconductor layer 128 as a characteristic configuration according to the present invention. A transparent conductive layer 143 of the second metal nanowires is formed by coating the entire surface over the second P layer 126 using a device (not shown) or a spin coating device (not shown), and drying and curing the same.

In this case, the transparent conductive layer 143 of the second metal nanowire has a light transmittance of 80% to 99%, and its sheet resistance is 1 kW / sq to 100 kW / sq. When the thickness of the transparent conductive layer 143 of the first metal nanowire is increased, the density of the metal nanowire is increased to decrease the sheet resistance, but the permeability is also reduced, so that the thickness is appropriately adjusted so that the aforementioned transmittance is 80% to 99%. It is preferable that the sheet resistance is in the range of 1 kW / sq to 100 kW / sq.

The transparent conductive layer 143 of the second metal nanowire has a network structure in which a plurality of metal nanowires 147 having a shape as shown in FIGS. 5A to 5C cross each other as shown in FIG. 3. It has a conductive property as a whole, and reflects the surface property of the second P / I / N junction semiconductor layer 128 provided under the surface thereof, which has a concave-convex structure.

In this case, the transparent conductive layer 143 of the second metal nanowires formed on the second P layer 126 is preferably made of gold (Au) exhibiting surface plasmon resonance at a long wavelength. .

Meanwhile, in the manufacturing method according to the present invention, the step of forming the transparent conductive layer 141 of the first metal nanowire on the first P layer 119 is omitted, but as a modification, the first P layer 119 is modified. The transparent conductive layer 141 of the first metal nanowire may be formed by performing the above process on the upper portion of the first metal nanowire.

Next, by depositing an n-type impurity semiconductor material, an amorphous silicon and a p-type impurity semiconductor material in succession on the transparent conductive layer 143 of the second metal nanowire, the third N layer 130, each surface of the concave-convex structure, A third P / I / N junction semiconductor layer 136 composed of the third I layer 132 and the third P layer 134 is formed. At this time, the third N layer 130, the third I layer 132 and the third P layer 134 is also characterized in that its surface naturally forms an uneven structure.

 Next, the same process as that of forming the transparent conductive layer 143 of the second metal nanowire on the third P layer 134 is performed to form the transparent conductive layer 145 of the third metal nanowire. In this case, the transparent conductive layer 145 of the third metal nanowire also has a light transmittance of 80% to 99%, and its sheet resistance is 1 kW / sq to 100 kW / sq. In addition, the transparent conductive layer 145 of the third metal nanowire may have a third P / I / N junction semiconductor layer 136 disposed below the second P / I / N junction semiconductor layer 128. Since the light absorbs the short wavelength band, it is preferable to be made of the metal nanowire made of silver (Ag) material in order to improve the scattering characteristics of the light of the short wavelength band than the transparent conductive layer 143 of the second metal nanowire.

Next, when the solar cell is configured by a plurality of cells, the transparent conductive layers 141, 143 and 145 of the first, second and third metal nanowires and the first, second and third P / I are irradiated with a laser beam. The / N junction semiconductor layers 120, 128, and 136 may be patterned. In this case, the transparent conductive layers 141, 143, and 145 of the first, second, and third metal nanowires and the first agent are formed in the same manner as the first transparent electrode 113 is patterned by irradiating a laser beam of high energy density or high power. The 1, 2 and 3 P / I / N junction semiconductor layers 120, 128 and 136 are patterned.

In the case of forming a solar cell composed of one cell, the first, second and third P / I / N junctions of the transparent conductive layers 141, 143 and 145 of the first, second and third metal nanowires using the laser device are formed. The patterning process of the semiconductor layers 120, 128, and 136 may be omitted.

Next, on the transparent conductive layer 145 of the third metal nanowire, a transparent conductive oxide such as GZO (gallium-zinc-oxide), AZO (aluminum-zinc-oxide), ZnO (zinc-oxide), SnO (tin- Oxide) to form a second transparent electrode 140, and the second transparent electrode 140 and the first, second, and third P / I / N junction semiconductor layers 120 and 128 thereon. The solar cell 100 according to the present invention can be completed by providing a transparent second insulating substrate 150 for the protection of 136.

In this case, although not shown in the drawings, an adhesive layer is interposed between the second insulating substrate 150 and the second transparent electrode 140 to maintain the two components in a bonded state.

100 solar cell 110 first insulating substrate
111: reflector 113: first transparent electrode
115: first N layer 117: first I layer
119: first P layer 120: first P / I / N junction semiconductor layer
122: second N layer 124: second I layer
126: second P layer 128: second P / I / N junction semiconductor layer
130: third N layer 132: third I layer
134: third P layer 136: third P / I / N junction semiconductor layer
140: second transparent electrode 141: first transparent conductive layer
143: second transparent conductive layer 145: third transparent conductive layer
150: second insulating substrate

Claims (13)

A first insulating substrate;
A first transparent electrode formed on the first insulating substrate;
A first P / I / N junction semiconductor layer formed on the first transparent electrode and sequentially formed of an n-type impurity semiconductor material layer, a hydrogenated silicon layer, and a p-type impurity semiconductor material layer;
A first transparent conductive layer having a networked structure of metal nanowires formed on the first P / I / N junction semiconductor layer;
A second transparent electrode formed on the first transparent conductive layer
Solar cell comprising a.
The method of claim 1,
Second and third P / I / N junction semiconductor layers having the same configuration as the first first P / I / N junction semiconductor layer between the first transparent electrode and the first P / I / N junction semiconductor layer. The solar cell is characterized in that formed.
The method of claim 2,
The first, second, 3 P / I / N junction semiconductor layer is characterized in that the energy band gap formed in order in order to have a large order.
The method of claim 3, wherein
The first I layer of the first P / I / N junction semiconductor layer is made of hydrogenated fine crystalline silicon,
The second I layer of the second P / I / N junction semiconductor layer is made of hydrogenated amorphous silicon mixed with germanium (Ge),
And a third I layer of the third P / I / N junction semiconductor layer is made of mixed hydrogenated amorphous silicon.
The method of claim 2,
And a second transparent conductive layer having a structure in which metal nanowires are networked between the second P / I / N junction semiconductor layer and the third P / I / N junction semiconductor layer.
The method of claim 5, wherein
And a third transparent conductive layer having a structure in which metal nanowires are networked between the first P / I / N junction semiconductor layer and the second P / I / N junction semiconductor layer.
The method according to claim 6,
In the first, second, and third transparent conductive layer, the metal nanowires are made of silver (Ag) or gold (Au).
The method of claim 7, wherein
The first, second, and third transparent conductive layers have a light transmittance of 80% to 99% and a sheet resistance of 1 kW / sq to 100 kW / sq.
The method of claim 1,
The solar cell of claim 1, wherein a reflective plate is provided between the first insulating substrate and the first transparent electrode or on an outer surface of the first insulating substrate.
The method of claim 1,
The first and second transparent electrodes are formed of any one of GZO (gallium-zinc-oxide), AZO (aluminum-zinc-oxide), ZnO (zinc-oxide), and SnO (tin-oxide), respectively. .
The method of claim 1,
The first transparent electrode, the first P / I / N junction semiconductor layer and the first transparent conductive layer, the surface of each of the solar cell, characterized in that the concave-convex structure.
The method of claim 2,
The first transparent electrode, the first, 2, 3 P / I / N junction semiconductor layer and the first, 2, 3 transparent conductive layer, the surface of each of the solar cell, characterized in that the concave-convex structure.
The method according to any one of claims 1, 5 and 6,
The metal nanowire is a solar cell, characterized in that the shape of the cylinder, triangular prism, square pillar shape.

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