KR20150118260A - Light absorber layer, method for fabricating the same, and solar cell and electrinic device using the same - Google Patents

Abstract

According to an embodiment of the present invention, provided is a light absorbing layer which is manufactured on a substrate; includes: copper, indium, gallium, and selenium elements; and has the surface roughness (Rz) of 30 nm or greater and 150 nm or smaller.

Description

TECHNICAL FIELD [0001] The present invention relates to a light absorbing layer, a method of manufacturing a light absorbing layer, and a solar cell and an electronic apparatus using the same,

The present invention relates to a light absorbing layer, a method for manufacturing a light absorbing layer, and a solar cell and an electronic apparatus using the same.

More particularly, the present invention relates to a CIGS light absorbing layer and a method of manufacturing the same, and more particularly, to a roll-to-roll process capable of producing a CIGS light absorbing layer at a higher speed than in the past, Solar cells and electronic devices.

Recently, serious environmental pollution problem and depletion of fossil energy are increasing importance for next generation clean energy development. Among them, solar cells are devices that convert solar energy directly into electrical energy, and are expected to be an energy source that can solve future energy problems because it has fewer pollution, has endless resources, and has a semi-permanent lifetime.

Photovoltaic cells are classified into various types according to the material used as a light absorbing layer, and silicon solar cells using silicon are the most widely used. However, recently, due to a shortage of supply of silicon, the price of solar cells has increased and interest in thin film solar cells is increasing.

Thin-film solar cells are manufactured with a thin thickness, so they have a wide range of applications because of low consumption of materials and light weight. Research on CIGS (CuIn1-xGaxSe2) has been actively conducted as a material of such a thin film solar cell.

The CIS or CIGS thin film is one of the Ⅰ-Ⅲ-Ⅳ compound semiconductors, and it has the highest conversion efficiency (about 20.3%) among the thin-film solar cells produced from the experimental results. In particular, it can be manufactured to a thickness of less than 10 microns and has stable characteristics even when used for a long time, and is expected to be a low-cost, high-efficiency solar cell that can replace silicon.

However, it is currently difficult to produce such a CIS or CIGS thin film at a high yield while achieving high quality. In order to commercialize a high efficiency solar cell, a CIS or CIGS thin film is manufactured with high quality and high productivity The research on the method is urgent.

An object of the present invention is to provide a method for manufacturing a CIGS light absorbing layer at a high speed.

Another object of the present invention is to provide a CIGS light absorbing layer having excellent light absorptivity, a solar cell including the same, and an electronic apparatus.

According to an embodiment of the present invention, there is provided a light absorbing layer which is made on a substrate and includes copper, indium, gallium and selenium, and has a surface roughness (Rz) of 30 nm or more and 150 nm or less.

The average thickness of the light absorbing layer is 0.8 μm or more and 10 μm or less.

The light absorbing layer may be manufactured using a roll-to-roll process.

According to another embodiment of the present invention there is provided a light absorbing layer made on a substrate and comprising copper, indium, gallium and selenium elements, wherein the light absorbing layer is formed by electrodepositing copper, indium and gallium The time for electrodeposition of copper on the substrate is 2 seconds or more and 20 seconds or less, the time for electrodeposition of indium on the substrate is 3 seconds or more and 20 seconds or less, and the time for electrodepositing gallium on the substrate Is not less than 3 seconds and not more than 10 seconds.

The concentration of the copper solution used to deposit the copper on the substrate may be 0.5M or more and 2M or less.

The concentration of the indium solution used to deposit the indium on the substrate may be 0.5M or more and 2M or less.

The concentration of the gallium solution used for electrodepositing the gallium on the substrate may be 0.5M or more and 2M or less.

The current density used to deposit the copper on the substrate may be 8.0 A / dm2 or more and 12.0 A / dm2 or less.

The current density used to deposit the indium on the substrate may be 9.0 A / dm2 or more and 11.0 A / dm2 or less.

The current density used to deposit the gallium on the substrate may be 10.0 A / dm2 or more and 20.0 A / dm2 or less.

According to another embodiment of the present invention, there is provided a solar cell including the above-described light absorbing layers.

According to another embodiment of the present invention, there is provided an electronic apparatus including the above-described light absorbing layers.

According to the present invention, as compared with the conventional method of manufacturing a light absorbing layer, it is possible to provide a method of manufacturing a light absorbing layer by using an electrochemical deposition method using a solution containing no organic additive that can act as an inhibitor or an accelerator, It is possible to form an electrodeposited thin film of each element in a very short time. By not using such an organic additive, the purity and performance of the light absorbing layer produced by the present invention can be further improved, and the cost for the organic additive that has been used can be reduced.

According to the present invention, on the other hand, by using higher concentrations and higher current densities than conventional methods, without using organic additives which can act as inhibitors or accelerators, The electrodeposited thin film can be formed. Particularly, by solving the problem that can be caused by using a high concentration and a high current density by adjusting the supply speed of the source solution, the performance is further improved and the light absorbing layer can be manufactured more quickly.

1 is a process block diagram illustrating a manufacturing process for manufacturing a light absorbing layer according to an embodiment of the present invention.
Fig. 2 is a SEM photograph of a section of a light absorbing layer (control group A) produced by a conventional method of producing a light absorbing layer before selenization.
3 is a view showing a surface SEM photograph of the light absorbing layer (control group A) produced by the conventional method of producing a light absorbing layer before selenization.
4 is a cross-sectional SEM photograph of the light absorbing layer (control group A) produced by the conventional method of producing a light absorbing layer after selenization.
5 is a SEM photograph of a light absorbing layer (control group A) produced by a conventional method of producing a light absorbing layer after selenization.
6 is a view showing a surface SEM photograph of the light absorbing layer (control group B) prepared by the conventional method of producing a light absorbing layer before selenization.
7 is a cross-sectional SEM photograph of a light absorbing layer (control group B) produced by a conventional method for producing a light absorbing layer after selenization.
FIG. 8 is a SEM photograph of a light absorbing layer (control group B) produced by a conventional method for producing a light absorbing layer after selenization.
Fig. 9 is a SEM photograph of a cross-section of a light absorption layer (experimental group) manufactured by a manufacturing method according to an embodiment of the present invention.
10 is a view showing a surface SEM photograph of a light absorbing layer (experimental group) produced by the method of manufacturing a light absorbing layer according to an embodiment of the present invention before selenization.
11 is a cross-sectional SEM photograph of a light absorbing layer (experimental group) produced by the method of manufacturing a light absorbing layer according to an embodiment of the present invention after selenization.
12 is a SEM photograph of a light absorbing layer (experimental group) produced by the method of manufacturing a light absorbing layer according to an embodiment of the present invention after selenization.
13 is a graph showing the roughness of the surface before selenization of the light absorbing layer (control group B) produced by the conventional method of manufacturing a light absorbing layer.
Fig. 14 is a graph showing the roughness of the surface after selenization of the light absorbing layer (control group B) produced by the conventional method of manufacturing a light absorbing layer.
15 is a graph showing the roughness of the surface before selenization of the light absorbing layer (experimental group) produced by the method of manufacturing the light absorbing layer according to one embodiment of the present invention.
16 is a graph showing the roughness of the surface after selenization of the light absorbing layer (experimental group) produced by the method of manufacturing the light absorbing layer according to one embodiment of the present invention.

The above objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. It is to be understood, however, that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities.

In the drawings, the thicknesses of the layers and regions are exaggerated for clarity and the element or layer is referred to as being "on" or "on" Included in the scope of the present invention is not only directly above another element or layer but also includes intervening layers or other elements in between. Like reference numerals designate like elements throughout the specification.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. In addition, numerals (e.g., first, second, etc.) used in the description of the present invention are merely an identifier for distinguishing one component from another.

In the present specification, CIGS means a compound represented by Cu (InxGa (1-x)) Sen (where x is a number between 0 and 1). At this time, in many cases, n is often 2, but n does not necessarily have to be 2.

In this specification, the X element solution means that the X element exists in the solution in the ion state by an electrochemical deposition method. That is, the copper solution refers to a solution in which copper ions are ionized. However, the X element solution may contain not only the ions of the X element but also other ions ionized from the compound for supplying the ions of the X element.

1 is a process block diagram illustrating a manufacturing process for manufacturing a light absorbing layer according to an embodiment of the present invention.

According to one embodiment of the present invention, the substrate 100 for manufacturing the light absorbing layer is wound on the first roll R1.

Meanwhile, the substrate 100 may have a conductive layer formed thereon for depositing the light absorbing layer according to the present invention. For example, a molybdenum (Mo) thin film may be formed on the substrate 100.

The substrate 100 wound on the first roll R1 is made of copper (Cu), indium (In) and gallium (Ga), while passing through a first process block 200 for electrodepositing the elements for forming a light absorption layer. Are electrodeposited on the substrate (100). That is, while passing through the first process block 200, the substrate 100 may be provided with a copper-indium / gallium or copper-selenium / indium-selenium / gallium-selenium, copper-selenium / indium / gallium, A thin film including indium-gallium-selenium / indium / gallium is stacked.

The substrate 100 having passed through the first process block 200 passes through a second process block 300. The selenium (Se) element passes through the first process block 200 of copper / indium / gallium while passing through the second process block 300 and the copper / indium / gallium or copper- Indium-gallium-indium-gallium-indium-gallium-indium-selenium / gallium-selenium copper-selenium indium gallium copper indium gallium selenium indium gallium can be supplied to the thin film, .

The substrate 100 having passed through the first process block 200 and the second process block 300 is wound again on the second roll R2. The substrate wound on the second roll R2 may be a substrate having a light absorbing layer according to an embodiment of the present invention.

Hereinafter, each process will be described more specifically.

First, the first process block 200 will be described.

The first process block 200 may include a first electrodeposited block 210, a second electrodeposited block 220 and a third electrodeposited block 230.

The first to third electrodeposited blocks 210, 220, and 230 are blocks for depositing copper, indium, and gallium, respectively, on the substrate 100. Although the order of electrodeposition of copper, indium, and gallium may be randomly selected, in embodiments of the present invention, copper is deposited first, followed by indium and gallium electrodeposited. That is, the first electrodeposition block 210 is a block for electrodepositing copper, the second electrodeposition block 220 is a block for electrodeposition of indium, and the third electrodeposition block 230 is a block for electrodepositing copper, A block for electrodeposition will be described as an example.

The first electrodeposited block 210 includes a copper-solution bath. The substrate 100 may be immersed in the copper solution container while passing through the first electrodeposition block 210.

The time during which the substrate 100 is immersed in the copper solution container (hereinafter referred to as a first time) can be finely controlled by process conditions according to an embodiment of the present invention. According to the present invention, May be in a range of 2 seconds to 300 seconds, and preferably the first time is 3 seconds to 20 seconds.

While the substrate 100 is immersed in the copper solution container, copper ions or copper atoms contained in the copper solution container may be electrodeposited on the substrate 100 through the electrochemical deposition method in the copper solution container have.

At this time, the copper solution in the copper solution container may have a concentration (hereinafter referred to as a first concentration) of copper ions (Cu +) of 0.1M or more and 2M or less, and preferably the first concentration is 0.5M or more and 1M or less.

Meanwhile, the density of the current (hereinafter referred to as a first current density) flowing in order to deposit the copper ion or copper atom through the electrochemical deposition method in the copper solution vessel may be 2.0 A / dm 2 or more and 15.0 A / dm 2 or less , And preferably, the first current density is 8.0 A / dm2 or more and 12.0 A / dm2 or less.

Meanwhile, the copper solution container may be connected to a copper solution source 210S for providing the copper solution. At this time, the copper solution may be supplied from the copper solution source 210S, and the rate at which the copper solution is supplied from the copper solution source 210S (hereinafter referred to as a first electrolyte supply rate) Lt; / RTI > As the variable for changing the first electrolyte supply rate, the copper ion concentration of the copper solution in the copper solution vessel may be used. For example, as described above, when the copper ion concentration of the copper solution is maintained within the above-described concentration range, a high quality copper thin film can be formed. To this end, (Not shown), and the first electrolyte supply rate may be adjusted according to the value of the copper ion concentration measured by the measurement apparatus. That is, if it is determined that the copper ion concentration is at a low level, the first electrolyte supply rate may be adjusted to be higher, and if it is determined that the copper ion concentration is at a high level, .

In addition, the copper solution does not include an organic additive that can act as an inhibitor or an accelerator.

The second electrodeposition block 220 includes an indium solution bath. The substrate 100 having passed through the first electrodeposition block 210 may be immersed in the indium solution container while passing through the second electrodeposition block 220.

The time during which the substrate 100 is immersed in the indium solution container (hereinafter referred to as a second time) can be finely controlled by process conditions according to an embodiment of the present invention. According to the present invention, May be in a range of 2 seconds to 300 seconds, and preferably, the second time is 3 seconds or more and 30 seconds or less.

While the substrate 100 is immersed in the indium solution container, indium ions or indium atoms contained in the indium solution container may be electrodeposited on the substrate 100 through the electrochemical deposition method in the indium solution container have.

At this time, the indium solution in the indium solution container may have a concentration (hereinafter referred to as a second concentration) of indium ions (In3 +) of 0.1 M or more and 2 M or less, and preferably the second concentration is 0.5 M or more and 1 M or less.

Meanwhile, the density of the current (hereinafter referred to as a second current density) to be deposited for depositing the indium ion or indium atom through the electrochemical deposition method in the indium solution container may be 8.0 A / dm2 or more and 15.0 A / dm2 or less , And preferably the second current density is 9.0 A / dm2 or more and 11.0 A / dm2 or less.

Meanwhile, the indium solution container may be connected to an indium solution source 220S for providing the indium solution. At this time, the indium solution may be supplied from the indium solution source 220S, and the rate at which the indium solution is supplied from the indium solution source 220S (hereinafter referred to as the second electrolyte supply rate) Lt; / RTI > The indium ion concentration of the indium solution in the indium solution container may be used as a parameter for changing the second electrolyte supply rate. For example, as described above, when the indium ion concentration of the indium solution is maintained within the above-described concentration range, a high-quality indium thin film can be formed. To this end, (Not shown), and the second electrolyte supply rate may be adjusted according to the value of the indium ion concentration measured by the measurement apparatus. That is, if it is determined that the indium ion concentration is at a low level, the second electrolyte supply rate may be adjusted to be higher, and if it is determined that the indium ion concentration is at a high level, .

In addition, the indium solution does not include an organic additive that can act as an inhibitor or an accelerator.

The third electrodeposition block 230 includes a gallium solution bath. The substrate 100 having passed through the second electrodeposition block 220 may be immersed in the gallium solution container while passing through the third electrodeposition block 230.

The time during which the substrate 100 is immersed in the gallium solution container (hereinafter referred to as a third time) can be finely controlled by process conditions according to an embodiment of the present invention. According to the present invention, May be in the range of 2 seconds to 30 seconds, and preferably the third time is 5 seconds or more and 30 seconds or less.

While the substrate 100 is immersed in the gallium solution container, gallium ions or gallium atoms contained in the gallium solution container may be electrodeposited on the substrate 100 through the electrochemical deposition method in the gallium solution container have.

At this time, the gallium solution in the gallium solution container may have a concentration of gallium ion (Ga3 +) (hereinafter referred to as a third concentration) of 0.1M or more and 2M or less, and preferably, the third concentration is 0.5M or more and 1M or less.

On the other hand, the density of the current (hereinafter referred to as the third current density) flowing for depositing the gallium ions or the gallium atoms through the electrochemical deposition method in the gallium solution container may be 8.0 A / dm 2 or more and 20.0 A / dm 2 or less , And preferably the third current density is 10.0 A / dm2 to 20.0 A / dm2.

Meanwhile, the gallium solution vessel may be connected to a gallium solution source 230S for providing the gallium solution. At this time, the gallium solution may be provided from the gallium solution source 230S, and the rate at which the gallium solution is supplied from the gallium solution source 230S (hereinafter referred to as a third electrolyte supply rate) Similar to the second electrolyte feed rate, may vary depending on the concentration of the gallium solution.

Also, the gallium solution does not include an organic additive that can act as an inhibitor or an accelerator.

Meanwhile, since the method of manufacturing the light absorbing layer according to an embodiment of the present invention uses the roll-to-roll process, the moving speed of the substrate 100 can be the same for all of the first to third electrodeposited blocks 210, 220 and 230 have. At this time, in order to control the immersion time of each of the first to third electrodeposition blocks 210, 220 and 230, the electrodeposited blocks 210, 220 and 230 are provided with a substrate path substrate path can be adjusted.

That is, when the first time for immersing the substrate 100 in the copper solution is longer than the second time for immersing the substrate 100 in the indium solution, the substrate 100 is immersed in the copper solution container May be set longer than the second substrate path in which the substrate 100 is immersed in the indium solution container and moved.

The second process block 300 will now be described.

A thin film of Cu, In, or Ga obtained through electrochemical electrodeposition on a substrate 100 is referred to as a precursor.

In the second process block 300, the precursor is treated in a temperature range from a minimum temperature of 400 ° C to a maximum temperature of 600 ° C in a range of 5 minutes to 60 minutes in which selenium gas is present in a saturated state. By the process in the second process block 300, the precursor is crystallized, and a CIGS light absorption layer is produced through the crystallization.

At this time, the average thickness of the light absorbing layer according to an embodiment of the present invention may be 0.8 μm or more and 10 μm or less.

The manufacturing method of the light absorbing layer according to the embodiment of the present invention has been described above.

According to the present invention, as compared with the conventional method of manufacturing a light absorbing layer, it is possible to provide a method of manufacturing a light absorbing layer by using an electrochemical deposition method using a solution containing no organic additive that can act as an inhibitor or an accelerator, It is possible to form an electrodeposited thin film of each element in a very short time. By not using such an organic additive, the purity and performance of the light absorbing layer produced by the present invention can be further improved, and the cost for the organic additive that has been used can be reduced.

According to the present invention, a light absorption layer is formed at a higher concentration and a higher current density than conventional methods without using an organic additive that can act as a commonly used inhibitor or accelerator . In other words, according to the present invention, a thin film deposited with each element is formed at a higher solution rotation speed. According to the present invention, the problem that can be caused by using a high concentration and a high current density is solved by adjusting the feeding rate of the electrolyte, so that the performance as a light absorbing layer including the surface roughness of the light absorbing layer is further improved, The light absorbing layer can be manufactured more quickly than the conventional method.

Generally, when the current density exceeds the critical current density, hydrogen gas is generated simultaneously with the reduction of copper ions, so that the electrodeposited layer may be oxidized (or burned). In order to solve this problem, .

Furthermore, assuming that selenization under the same conditions is carried out, the surface roughness of the light absorbing layer formed by electrodeposition at a relatively high concentration for a short time according to the present invention is electrodeposited for a long time at a relatively low concentration as in the conventional method The inventors of the present invention have confirmed that the performance as a light absorbing layer is further improved by lowering the surface roughness of the formed light absorbing layer. The present inventors have confirmed that the surface roughness Rz of the light absorption layer produced according to an embodiment of the present invention is in the range of 30 nm or more and 150 nm or less.

The inventors of the present invention analyzed the phenomenon that the surface roughness of the light absorption layer formed by the present invention is improved as compared with the conventional art. Generally, when each element is electrodeposited on a substrate, nuclei are formed on the surface of the substrate at the initial stage of electrodeposition, and each layer grows around the nucleus. However, when a low concentration solution and a low current density are used, fewer nuclei are generated per unit area in the initial stage of electrodeposition than when a high concentration solution and a high current density are used as in the present invention The surface of each layer can be more uniformly grown when each layer is grown from a larger number of nuclei per unit area than when each layer is grown from a smaller number of nuclei per unit area , It is analyzed that the surface roughness of the light absorbing layer formed by the present invention can be improved as compared with the prior art. That is, in the conventional case, as fewer nuclei are formed per unit area, the surface roughness becomes uneven and rugged if each layer grows for a longer time centered on the nucleus. However, according to the present invention , More nuclei per unit area, so that when each layer grows for a shorter time around the nucleus, the surface roughness becomes relatively flat. This phenomenon occurs in an overlapping manner in the electrodeposition process of indium and gallium deposited on the copper surface. As a result, it has been observed that the surface roughness of the light absorption layer becomes lower when compared with the conventional case. Accordingly, the performance of the light absorbing layer according to the present invention can have a better performance than the light absorbing layer manufactured by the conventional method.

Hereinafter, an experimental example of a method of manufacturing the light absorbing layer according to the present invention will be described.

[Experimental Example]

The present inventors have made several light absorbing layers according to the conventional method of the present invention, using the following experimental conditions.

<Control A>

The copper solution used was a copper solution with a copper concentration of 0.1M, and a solution of CuSO4 / 5H2O and H2SO4 in a ratio of 1: 1 was used as the copper solution. The current density was 0.6 A / dm 2, the electrodeposition time was 10 seconds, and the electrodeposition temperature was room temperature.

An indium solution having an indium concentration of 0.1 M was used as the indium solution, and a solution in which at least one of InCl 3 / 4H 2 O and NaCl, Na 2 SO 4, NaClO 4, KCl and KNO 3 was mixed as the indium solution was used. The current density was 0.5 A / dm 2, the electrodeposition time was 10 seconds, and the electrodeposition temperature was room temperature.

The gallium solution used was a gallium solution with a gallium concentration of 0.1 M and a solution of GaCl 3 and at least one of NaCl, Na 2 SO 4, NaClO 4, KCl and KNO 3 in a ratio of 1: 1 was used as the gallium solution. The current density was 0.2 A / dm 2, the electrodeposition time was 10 seconds, and the electrodeposition temperature was room temperature.

The electrodeposited thin film (precursor) was treated in the temperature range of 400 ~ 600 ℃ for 5 ~ 60 minutes in which the selenium gas existed in the saturated state and the selenization proceeded.

<Control B>

The copper solution used was a copper solution with a copper concentration of 0.1M, and a solution of CuSO4 / 5H2O and H2SO4 in a ratio of 1: 1 was used as the copper solution. The current density was 0.6 A / dm 2, the electrodeposition time was 120 seconds, and the electrodeposition temperature was room temperature.

An indium solution having an indium concentration of 0.1 M was used as the indium solution, and a solution in which at least one of InCl 3 / 4H 2 O and NaCl, Na 2 SO 4, NaClO 4, KCl and KNO 3 was mixed as the indium solution was used. The current density was 0.5 A / dm 2, the electrodeposition time was 180 seconds, and the electrodeposition temperature was room temperature.

The gallium solution used was a gallium solution with a gallium concentration of 0.1 M and a solution of GaCl 3 and at least one of NaCl, Na 2 SO 4, NaClO 4, KCl and KNO 3 in a ratio of 1: 1 was used as the gallium solution. The current density was 0.2 A / dm 2, the electrodeposition time was 180 seconds, and the electrodeposition temperature was room temperature.

The electrodeposited thin film (precursor) was treated in the temperature range of 400 ~ 600 ℃ for 5 ~ 60 minutes in which the selenium gas existed in the saturated state and the selenization proceeded.

<Experiment group>

The present inventors have produced a light absorbing layer according to an embodiment of the present invention using the following experimental conditions.

The copper solution used was a copper solution with a copper concentration of 1M, and a solution of CuSO4 / 5H2O and H2SO4 in a ratio of 1: 1 was used as the copper solution. The current density was 12 A / dm 2, the electrodeposition time was 10 seconds, and the electrodeposition temperature was room temperature.

 An indium solution having an indium concentration of 1 M was used as the indium solution, and a solution in which at least one of InCl 3 / 4H 2 O and NaCl, Na 2 SO 4, NaClO 4, KCl and KNO 3 was mixed as the indium solution was used. The current density was 10 A / dm 2, the electrodeposition time was 10 seconds, and the electrodeposition temperature was room temperature.

The gallium solution used was a gallium solution with a gallium concentration of 1 M, and a solution of GaCl 3 and at least one of NaCl, Na 2 SO 4, NaClO 4, KCl and KNO 3 in a 1: 1 ratio was used as the gallium solution. The current density was 20 A / dm 2, the electrodeposition time was 10 seconds, and the electrodeposition temperature was room temperature.

The electrodeposited thin film (precursor) was treated in the temperature range of 400 ~ 600 ℃ for 5 ~ 60 minutes in which the selenium gas existed in the saturated state and the selenization proceeded.

Experimental conditions for the control groups A and B and experimental groups are summarized in Table 1 below.

Control A Control group B Experimental group Copper solution concentration (moles) 0.1 0.1 One Current density at copper deposition (A / dm2) 0.6 0.6 12 Copper electrodeposition time (sec) 10 120 10 Copper deposition temperature Room temperature Room temperature Room temperature Indium solution concentration (moles) 0.1 0.1 One Current density (A / dm2) upon indium electrodeposition 0.5 0.5 10 Indium electrodeposition time (sec) 10 180 10 Indium electrodeposition temperature Room temperature Room temperature Room temperature Gallium solution concentration (mol) 0.1 0.1 One Current density at gallium deposition (A / dm2) 0.2 0.2 20 Gallium Electrodeposition Time (sec) 10 180 10 Gallium deposition temperature Room temperature Room temperature Room temperature Selenization temperature (캜) / hour (minute) 400 ~ 600/5 ~ 60 Same as left Same as left

FIG. 2 is a cross-sectional SEM photograph of a light absorbing layer (control group A) produced by a conventional method of producing a light absorbing layer before selenization, and FIG. 3 is a graph showing a SEM photograph of a light absorbing layer FIG. 4 is a cross-sectional SEM photograph of a light absorbing layer (control group A) produced by a conventional method of manufacturing a light absorbing layer after selenization, and FIG. 5 is a cross- (SEM photograph) of the light absorbing layer (control group A) produced by the light absorbing layer production method after selenization.

Fig. 6 is a SEM photograph of a surface of a light absorbing layer (control group B) prepared by a conventional method of producing a light absorbing layer before selenization, and Fig. 7 is a graph showing a SEM photograph of a light absorbing layer FIG. 8 is a SEM photograph of a light absorbing layer (control group B) produced by a conventional method of producing a light absorbing layer after selenization. FIG.

9 is a cross-sectional SEM photograph of a light absorbing layer (experimental group) manufactured by a manufacturing method according to an embodiment of the present invention, and FIG. 10 is a cross-sectional view of a light absorbing layer manufacturing method according to an embodiment of the present invention (SEM) of the light absorbing layer (experimental group) produced by the method of manufacturing the light absorbing layer according to one embodiment of the present invention, FIG. 12 is a view showing a SEM photograph of a light absorbing layer (experimental group) produced by a light absorbing layer manufacturing method according to an embodiment of the present invention after selenization.

Referring to FIGS. 2 to 5 and 9 to 12, when a thin film (precursor) is formed for a relatively short time using each solution having a concentration of 0.1 M as in the condition of the control group A, It can be seen that not only the thin film is formed to a required thickness but also the thickness of the thin film to be formed is in a very uneven state in both cases before and after. The thickness of the thin film at 443.7 nm and 850.5 nm as shown in Fig. 2 showing the cross section of the precursor before selenization, and the thin film was not formed properly at the other portions. In addition, in the case of Fig. 4 showing the cross section after selenization, there is also a portion where the layer of 499.2 nm is formed, but it can be seen that there are many portions where the light absorbing layer is not properly formed.

On the other hand, when the thin film was formed for a relatively short time using each solution having a concentration of 1M as in the experimental group, as in the case of the embodiment of the present invention, It can be seen that the thickness is relatively uniform and the required thickness is formed as the light absorption layer. Referring to FIG. 9, which shows a cross section of the precursor before selenization, it can be seen that the thickness of the precursor is measured to be about 1.74 um and 1.82 um.

6 to 12, it can be seen that the thickness of the light absorbing layer of the control group B is similar to the thickness of the experimental group according to this embodiment of the present invention, but in the case of the control group B, the surface of the selenium precursor (thin film) Indium and gallium were electrodeposited around the copper nucleus where the first electrodeposition was carried out, showing a rugged surface, and the appearance remained after the selenization. That is, it can be seen that the uniformity of the pre-selenization precursor (thin film) and / or the light absorbing layer formed by the condition of the control group B is much lower than the uniformity of the precursor and / or the light absorbing layer formed by one embodiment of the present invention . This is attributed to the dependence of the number of nuclei per unit area formed on the substrate on the current density. It can be seen that as the current density is increased, the number of nuclei formed per unit area is further increased, It is interpreted that the thickness of the thin film formed around the core is more uniform.

In comparison with the light absorbing layer produced by the conventional method and the light absorbing layer produced by the present invention, the light absorbing layer according to the present invention can form a light absorbing layer having a required thickness in a shorter time Able to know

On the other hand, FIG. 13 shows a graph showing the roughness of the surface before selenization of the light absorbing layer (control group B) produced by the conventional method of manufacturing a light absorbing layer, and FIG. 14 is a graph showing the roughness And a surface roughness after selenization of the prepared light absorbing layer (control group B).

15 is a graph showing the roughness of the surface before selenization of the light absorbing layer (experimental group) produced by the method of manufacturing a light absorbing layer according to an embodiment of the present invention. FIG. 3 is a graph showing surface roughness after selenization of the light absorbing layer (experimental group) produced by the method of manufacturing a light absorbing layer according to one embodiment.

13 and 14, the thin film surface after selenization under the same conditions as the 0.1 M and 1 M precursors was analyzed using SPM. As a result, it was found that when the light absorbing layer was prepared at a low concentration (control group B) Selenium thin film), but also surface roughness after selenization.

Referring to FIGS. 15 and 16, in the case of the light absorbing layer (experimental group) manufactured in a short time using 1 M, a relatively low surface roughness value was exhibited both before and after selenization.

It can be seen from the experimental results that the surface roughness of the light absorption layer according to the present invention is further reduced when the light absorption layer produced by the conventional method is compared with the light absorption layer produced by the present invention.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, The present invention is not limited to the drawings. In addition, the embodiments described in this document can be applied to not only the present invention, but also all or some of the embodiments may be selectively combined so that various modifications can be made. Further, the steps constituting each embodiment can be used separately or in combination with the steps constituting the other embodiments.

Claims (8)

A light absorbing layer made on a substrate and comprising copper, indium, gallium and selenium elements,
When the surface roughness (Rz) of the light absorption layer is 30 nm or more and 150 nm or less
Light absorbing layer.
The method according to claim 1,
The average thickness of the light absorbing layer is not less than 0.8 μm and not more than 10 μm
Light absorbing layer.
The light-emitting device according to claim 1,
Characterized in that it is manufactured using a roll-to-roll process
Light absorbing layer.
A light absorbing layer made on a substrate and comprising copper, indium, gallium and selenium elements,
The light absorption layer is formed by electrodepositing copper, indium and gallium on a flexible substrate of a continuous phase,
The time for electrodepositing the copper on the substrate is 2 seconds or more and 20 seconds or less,
The time for electrodeposition of the indium on the substrate is 3 seconds or more and 20 seconds or less,
Wherein the time for electrodepositing the gallium on the substrate is not less than 3 seconds and not more than 10 seconds.
Light absorbing layer.
5. The method of claim 4,
The concentration of the copper solution used for electrodepositing the copper on the substrate is 0.5M or more and 2M or less,
The concentration of the indium solution used for electrodepositing the indium on the substrate is 0.5M or more and 2M or less,
And the concentration of the gallium solution used for electrodepositing the gallium on the substrate is not less than 0.5M and not more than 2M
Light absorbing layer.
5. The method of claim 4,
The current density used for electrodepositing the copper on the substrate is 8.0 A / dm2 or more and 12.0 A / dm2 or less,
The current density used to deposit the indium on the substrate is 9.0 A / dm2 or more and 11.0 A / dm2 or less,
And the current density used for electrodepositing the gallium on the substrate is not less than 10.0 A / dm 2 and not more than 20.0 A / dm 2
Light absorbing layer,
A solar cell comprising the light absorbing layer according to any one of claims 1 to 6.
An electronic device comprising the light absorbing layer according to any one of claims 1 to 6.

Images