CN103779438A - Method for preparing CuInxGaySez prefabricated layer by electrochemical deposition - Google Patents

Abstract

The invention belongs to the technical field of solar cells and particularly relates to a method for preparing a CuInxGaySez prefabricated layer by electrochemical deposition. The method comprises steps: in an electrical deposition solution, current pulse or voltage pulse is adopted to obtain a CuInxGaySez prefabricated layer on a cathode substrate through electrical deposition, and the current pulse or the voltage pulse comprises a positive pulse period when the current and the voltage are negative values on the deposition surface and a reverse pulse period when the current and the voltage are positive values on the deposition surface. According to the method, a reverse pulse method is used during the electrical deposition process, part of selenium is stripped back in an electroplating solution while the CuInxGaySez prefabricated layer is formed, generation of selenium balls is avoided, and thus the CuInxGaySez prefabricated layer which is uniform in compositions and stable in phase is formed.

Description

A kind of method for preparing copper indium gallium selenide prefabricated layer by electrochemical deposition

technical field

The invention belongs to the field of solar cells, and in particular relates to a method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition.

Background technique

With the continuous increase of human energy consumption, the depletion of non-renewable energy sources such as fossil fuels has become an urgent problem to be solved. The total consumption of fossil energy will reach an inflection point around 2030, and the proportion of renewable energy will continue to rise. Among them, the proportion of solar energy in the future energy structure will increase. It is conservatively estimated that this proportion will exceed 60% in 2100. Solar energy is the most abundant energy among many renewable energy sources. The energy of global sunlight for one hour is equivalent to the energy consumption of the earth for a year, which is much higher than wind energy, geothermal energy, hydropower, ocean energy, biomass energy and other energy sources.

The bottleneck restricting large-scale solar power generation is mainly the low conversion efficiency and high production cost of photovoltaic devices, the core element of which is the cost of photovoltaic power generation systems, including photovoltaic panels and other system components such as inverters, electrical switches, cables and bracket etc. To achieve “grid parity” for power generation, the cost of power generation must reach RMB 0.6 per kilowatt-hour, the cost of photovoltaic panels must be reduced to RMB 3-4 per watt, and the selling price should be RMB 5-7 per watt. Since the current market price of polysilicon photovoltaic panels is close to the cost price of enterprises, and the manufacturing technology of polysilicon photovoltaic panels is relatively mature, there is limited room for downward adjustment. It is not easy to achieve "grid parity" with polysilicon photovoltaic panels.

Copper indium gallium selenide (CuInxGaySez, can also include sulfur, abbreviated as CIGS) thin-film photovoltaic panels have become a research hotspot in the photovoltaic industry due to their high conversion efficiency, good long-term stability, and strong radiation resistance, and are expected to become the next generation of cheap photovoltaics. plate. It has the following advantages:

1) High photoelectric conversion efficiency. At present, the laboratory efficiency of CIGS thin-film photovoltaic panels on glass substrates has exceeded 20%, which is close to the world record of traditional crystalline silicon photovoltaic panels. The conversion efficiency of large-area CIGS thin-film photovoltaic panel modules also exceeds 14%, which is the highest among all thin-film photovoltaic panels;

2) Low light performance is good, and electricity can be generated even when the sun is not directly shining. From the actual operation experience of photovoltaic power plants, more electricity can be generated on cloudy days and in the morning and evening;

3) The temperature coefficient is low. When the temperature is high, including the local temperature is high or the temperature is high due to sunlight, CIGS photovoltaic panels can maintain a high conversion efficiency. Therefore, at the same efficiency, CIGS photovoltaic panels produce more electricity than traditional crystalline silicon photovoltaic panels;

4) Low cost and low material consumption;

5) Good long-term stability, no attenuation in outdoor use;

6) The energy repayment period is short;

7) Suitable for the development of multi-purpose flexible photovoltaic modules.

These advantages make copper indium gallium selenide thin film photovoltaic panels have broad application prospects in civilian and military fields, such as photovoltaic building integration, large-scale low-cost power stations, solar lighting sources, space and adjacent space systems, etc.

Copper indium gallium selenide thin film photovoltaic panel is a multilayer film structure, usually including: substrate, back electrode, CIGS absorber layer, buffer layer, transparent conductive layer, etc., among which CIGS absorber layer is the most critical component of solar photovoltaic panel, its preparation The method determines the quality and cost of photovoltaic panels.

At present, the production process of compound semiconductors widely used in optoelectronic devices in the market is almost always using high vacuum technology such as evaporation or sputtering, especially in the field of CIGS. However, the above-mentioned vacuum technology needs to consume a lot of cost in the initial investment and operation process. In addition, the size of the vacuum chamber of the instrument will also limit the output of the film, further affecting the production efficiency. The development of non-vacuum method is beneficial to the large-scale production of CIGS.

Nanosolar company took the lead in using ink printing to prepare CIGS thin film technology (see K. Pichler, US Patent No. 7,122,398 and references). The preparation process is: firstly prepare CIGS nanoparticles by chemical methods, then disperse these nanoparticles to form a colloidal solution (usually called CIGS nano-ink), add suitable surfactants to prevent the aggregation of nanoparticles, in addition to adding Other chemical additives required for the printing process. After the CIGS nano-ink is printed to form a thin film, it needs heat treatment to remove the previously added solvent, surfactant and other chemical additives, and then it can be sintered to form a uniform thin film.

Many conductive materials can be prepared on a large scale by low-cost electrochemical methods, and the preparation of CIGS thin films by electrodeposition has become one of the main research directions to reduce costs and obtain large-area CIGS thin films. At present, there are some problems in the electrochemical preparation of CIGS with a suitable stoichiometric ratio. The molar ratio of each element in the CIGS film is: Cu: (In+Ga): Se≈1:1:2, the conversion efficiency is high, and the Ga The conversion efficiency is the highest when the content is 0.3. For example, electrodeposition of CIGS requires strict control of the amount of Cu, In, Ga, and Se elements in the solution, accurate control of the electrochemical reduction potential, and control of the solution to prevent other side reactions during the electrochemical deposition process. Nonetheless, several research groups have reported that CIGS thin films have been electroplated in aqueous phase. For example: YPFu et al. (Journal of the Electrochemical Society, 2009, 156, 9–E133-E138) reported that CIGS thin films were prepared in aqueous solution using LiCl as the conductive salt. Due to the low deposition potential of In and Ga in the water-based electrolyte, a relatively negative deposition potential is used, and the cathode is easy to release hydrogen gas, making the film porous (hydrogen evolution reaction). In addition, they did not prepare films with proper stoichiometry, and the Ga content in the films was low. Addition of more Ga compounds in aqueous solutions does not increase the Ga content in CIGS films. Fu et al. pointed out that the addition of Ga compounds in aqueous solution leads to a more negative Ga reduction potential, and Ga ³⁺ is difficult to be reduced at the cathode.

Lai et al. (Electrochimica Acta 2009, 54, 3004-3010) reported one-step electrodeposition of CIGS thin films in a water-dimethylformamide system. Even in this system, it is difficult to co-deposit in one step due to the large difference in the reduction potentials of the four elements Cu, In, Ga, and Se. In order to solve this problem, Lai et al. added a complexing agent to the water-dimethylformamide system. In this document, they also analyzed the hydrogen evolution reaction mentioned above in detail, but the complexing agent sodium citrate Adding does not produce obvious complexation effect with In ³⁺ , Ga ³⁺ ions to change the reduction potential of In and Ga, which is at -0.3V, -0.4V, -0.5V, -0.6V, -0.7V, - The corresponding CuIn _0.21 Ga _0.10 Se _1.75 , CuIn _0.40 Ga _0.14 Se _1.41 , CuIn _0.35 Ga _0.12 Se _1.21 , CuIn _0.42 Ga _0.17 Se _1.24 , CuIn _{0.43 Ga} were prepared at the potentials of 0.8V, -0.9V, and -1.0V Se _1.32 , CuIn _0.47 Ga _0.22 Se _1.22 , CuIn _0.62 Ga _0.22 Se _1.20 , CuIn _0.57 Ga _0.16 Se _1.52 . These are not CIGS with proper stoichiometric ratio, all of which are rich in Cu and poor in In and Ga.

In another method, Kois et al. (Thin Solid Films 2008, 516, 5948-5952) reported the preparation of CIGS films using thiocyanate composite electrolytes. They again emphasized the necessity of selenization heat treatment after electroplating. And their report also showed that the Ga content in the CIGS film obtained by electroplating was insufficient.

In yet another approach, Long and co-workers (Journal of Physics: Conference Series 2009, 152, 012074) reported the one-step electrodeposition of CIGS thin films in ethanol solutions. Similarly, the CIGS film obtained after electroplating needs to be sintered at 550° C. for 30 minutes, and the Cu content in the obtained CIGS film is insufficient.

Peter et al reported the preparation of CIGS by electrodeposition in a non-aqueous phase ("Electrochemical Deposition of CIGS by means of Room Temperature Ionic Liquids", Thin solid Films, 2007, 515, 5899-5903). This document describes the preparation of Cu-In-Ga and Cu-In-Ga-Se thin films in ionic liquids. After electroplating, the thin films were selenized at 500°C for 30 minutes to prepare CIS and CIGS thin films with appropriate stoichiometric ratios, respectively.

The above literatures on electrodeposition mainly focus on the influence of electrodeposition liquid on the electrodeposition process. CN101079454A discloses a method for pulse electrodepositing copper indium gallium selenide semiconductor thin film material. The method adopts cathode pulse potential deposition method to deposit a prefabricated layer containing copper indium gallium selenide on the substrate. The pulse potential waveform is square wave, triangular wave or sine wave. CN101570871A discloses a method for depositing copper indium gallium selenide or copper indium gallium selenide semiconductor thin film material by using a special pulse power supply. The patent uses a square wave pulse adjusted by a bell wave to electrodeposit a prefabricated layer on the cathode substrate. The above two methods use pulse waves, although to some extent alleviate the problems of few controllable parameters of constant potential electrodeposition, severe hydrogen evolution reaction, and high film porosity; Due to the potential difference, the four elements cannot be co-deposited synchronously, especially the deposition rate of Se is fast, and a CIGS film with a suitable stoichiometric ratio cannot be obtained, and some pure selenium spheres (such as the spheres in Figure 1) are generated during the electrodeposition process. . These selenium balls will affect the formation of CIGS crystals, and will also cause small voids in the CIGS layer after annealing.

Contents of the invention

The object of the present invention is to overcome the shortcomings of the improper stoichiometric ratio in the CIGS film and the formation of almost pure selenium selenium balls in the coating that exist in the above-mentioned electrodeposition preparation of copper indium gallium selenium thin film technology, and provide an improved electrochemical deposition A method for preparing a copper indium gallium selenide prefabricated layer. The present invention utilizes reverse pulse electrochemical deposition to prepare the copper indium gallium selenium prefabricated layer. While forming the copper indium gallium selenium prefabricated layer, part of the selenium element is stripped back into the electroplating solution, which can avoid the formation of selenium balls in the plating layer. , so as to form a CIGS prefabricated layer with uniform composition and stable phase.

In order to realize the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

A method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition, comprising: in an electrodeposition solution, using a current control pulse or a voltage control pulse to electrodeposit a copper indium gallium selenide prefabricated layer on a cathode substrate, wherein the current The control pulse or voltage control pulse includes a forward pulse period in which the current and voltage both reach negative values on the deposition surface and a reverse pulse period in which both the current and voltage reach positive values on the deposition surface. The electrodeposition solution is an ionic liquid system. During the electrodeposition process, the selenium element deposited at a relatively low voltage can be deplated into the electrodeposition solution by using the reverse pulse, so as to avoid the formation of selenium balls in the plating layer.

Preferably, in the method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition, the pulse conditions of the current pulse are: the working time of the forward pulse period is 3 milliseconds to 1 second, and the current density is -0.05ASD to -5.0ASD ; The working time of the reverse pulse period is 1 millisecond to 0.5 seconds, and the current density is 0.1ASD to 20ASD; the pulse conditions of the voltage pulse are: the working time of the forward pulse period is 3 milliseconds to 1 second, and the voltage is -0.5V ~-8.0V; the working time in the reverse pulse period is 1 millisecond to 0.5 seconds, and the voltage is 0.1V to 5.0V. Under the above-mentioned pulse conditions, while the electrodeposition forms the prefabricated layer of copper indium gallium selenide, it is beneficial to deplating the segregated selenium element into the electrodeposition solution, and this deplating is selective, and almost no deplating of other elements can be obtained. CIGS film with proper stoichiometry avoids the formation of selenium balls in the coating.

In the method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition, the concentrations of copper, indium, gallium, and selenium ions in the electrodeposition solution are respectively 0.1mM-50mM, 0.1mM-60mM, 0.1mM-80mM, and 0.1mM-50mM .

The ionic liquid system is composed of urea and choline chloride, and the weight ratio of choline chloride to urea is 1:0.5-5, preferably 1:2.

In the above method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition, the copper ions in the electrodeposition solution come from sulfate, acetate, bromide, fluoride, chloride, iodide, hydrogen Oxides, nitrides, oxalates, citrates, phosphates, tungstates, hydrates, or combinations thereof.

In the above method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition, the gallium ions in the electrodeposition solution come from sulfate, acetate, bromide, fluoride, chloride, iodide, hydrogen containing gallium Oxides, nitrides, oxalates, citrates, phosphates, tungstates, hydrates, or combinations thereof.

In the above method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition, the indium ions in the electrodeposition solution come from sulfate, acetate, bromide, fluoride, chloride, iodide, hydrogen, etc. containing indium. Oxides, nitrides, oxalates, citrates, phosphates, tungstates, hydrates, or combinations thereof.

In the above method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition, the selenium ions in the electrodeposition solution come from sulfate, acetate, bromide, fluoride, chloride, iodide, hydrogen containing selenium Oxides, nitrides, oxalates, citrates, phosphates, tungstates, hydrates, or combinations thereof.

In the method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition, the substrate can be a conductive polymer, a polymer covered with a metal, a polymer covered with a transparent conductive layer, a glass covered with ITO, a polymer covered with ITO, Any one or combination of ceramics, metals, amorphous semiconductor materials, crystalline semiconductor materials, and polycrystalline semiconductor materials covering the conductive layer.

In the above method for preparing the CIGS prefabricated layer by electrochemical deposition, all or part of the copper ions in the electrodeposition solution enter the electrodeposition solution after being oxidized by the anode.

In the above method for preparing the CIGS prefabricated layer by electrochemical deposition, all or part of the gallium ions in the electrodeposition solution enter the electrodeposition solution after being oxidized by the anode.

In the above method for preparing the CIGS prefabricated layer by electrochemical deposition, all or part of the indium ions in the electrodeposition solution enter the electrodeposition solution after being oxidized by the anode.

In the above method for preparing the CIGS prefabricated layer by electrochemical deposition, all or part of the selenium ions in the electrodeposition solution enter the electrodeposition solution after being oxidized by the anode.

For the copper indium gallium selenium prefabricated layer prepared by the above electrochemical deposition method, the thickness of the prefabricated layer deposited by the reverse pulse is more than 20% of the thickness of the whole prefabricated layer. The inventors found that during the electrochemical deposition process, when the prefabricated layer prepared by using the reverse pulse is more than 20% of the thickness of the overall prefabricated layer, the formation of voids near the interface between the CIGS layer and the metal layer can be reduced.

Compared with prior art, the beneficial effect of the present invention:

In the process of preparing copper indium gallium selenide by electrochemical deposition, due to the potential difference of the four elements of copper indium gallium selenide, the degree of difficulty of electrolysis of each element is different, and the four elements cannot be co-deposited simultaneously, especially when Se is deposited at a relatively low voltage. , so it is difficult to obtain a CIGS film with a proper stoichiometric ratio, and some selenium spheres (such as the spheres in Figure 1) are generated during the electrodeposition process. These selenium balls affect the formation of CIGS crystals, and also cause small voids in the CIGS layer after annealing. In the method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition of the present invention, in the process of electrochemical deposition, the reverse pulse wave is used, and the copper indium gallium selenide prefabricated layer can be deposited at a relatively low voltage while preparing the copper indium gallium selenide prefabricated layer. Part of the selenium element is deplated into the electroplating solution to avoid the formation of selenium balls in the plating layer, thereby forming a copper indium gallium selenide prefabricated layer with uniform composition and stable phase.

The inventors found that during the electrochemical deposition process, when the prefabricated layer prepared by using the reverse pulse is more than 20% of the thickness of the overall prefabricated layer, the formation of voids near the interface between the CIGS layer and the metal layer can be reduced. Further, the inventors optimized the pulse conditions of the reverse pulse. Electrodeposition was performed during the forward pulse period when the current and voltage were both negative on the deposition surface, and during the reverse pulse period when the current and voltage were both positive on the deposition surface. Deplating, under the action of the above pulse conditions, while forming the prefabricated layer of copper indium gallium selenium by electrodeposition, it is beneficial to partially deplate the selenium element into the electrodeposition solution, almost no other elements are deplated, and the stoichiometric ratio can be obtained. Suitable CIGS thin film to avoid the formation of selenium balls in the coating.

Description of drawings:

FIG. 1 is an electron microscope scanning image of a CIGS prefabricated layer in the prior art, and the balls in the figure are selenium balls.

Fig. 2 is a graph of pulse current density and corresponding voltage change in Example 1.

Fig. 3 is a surface morphology diagram of Example 1 obtained by a scanning electron microscope.

Fig. 4 is a graph showing the pulse voltage and the corresponding current density changes in Example 2.

Fig. 5 is a surface morphology diagram of Example 2 obtained by a scanning electron microscope.

FIG. 6 is a diagram of constant current current density and corresponding voltage change in Comparative Example 1. FIG.

FIG. 7 is a surface morphology diagram of Comparative Example 1 obtained by a scanning electron microscope.

FIG. 8 is a graph showing constant voltage and corresponding current density changes in Comparative Example 2. FIG.

FIG. 9 is a surface morphology diagram of Comparative Example 2 obtained by a scanning electron microscope.

Detailed ways

The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

Example 1

The method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition listed in this embodiment includes electrodepositing the copper indium gallium selenide prefabricated layer on the cathode substrate by using a current pulse in an electrodeposition solution. The cathode substrate is soda-lime glass covered with a conductive molybdenum layer formed by vacuum sputtering. Wherein, the current pulse includes a forward pulse period in which the current and voltage are both negative on the deposition surface and a reverse pulse period in which the current and voltage are both positive on the deposition surface. The pulse current density and corresponding voltage change are shown in Figure 2, and the pulse current density and working time are shown in Table 1.

In this embodiment, the electrodeposition solution is an ionic liquid system, the ionic liquid system is composed of urea and choline chloride, and the weight ratio of choline chloride to urea is 1:0.5; copper, indium, gallium, selenium in the ionic liquid system The content and source of ions are shown in Table 2. The electrochemical deposition setup consists of a platinum sheet as the anode, a platinum wire as the reference electrode, and a power supply that provides reverse pulses. Electrochemical deposition is controlled by current, and the change of current and corresponding voltage is measured and recorded at the same time.

The surface morphology of the CIGS prefabricated layer prepared according to the method of this embodiment is scanned by an electron microscope. As shown in Figure 3, there is no spherical structure on the CIGS surface, and the X-ray energy spectrum shows that the content of selenium is 51.7%, and the overall composition conforms to copper indium gallium Selenium prefab layer required.

Example 2

The method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition in this embodiment includes electrodepositing the copper indium gallium selenide prefabricated layer on the cathode substrate by using voltage pulses in an electrodeposition solution. The cathode substrate is a glass substrate plated with Mo and Cu. Wherein, the voltage pulse includes a forward pulse period in which the current and voltage are both negative on the deposition surface and a reverse pulse period in which the current and voltage are both positive on the deposition surface. The pulse voltage and corresponding current density changes are shown in Figure 4, and the voltage and working time of the reverse pulse wave are shown in Table 1.

In this embodiment, the electrodeposition solution is an ionic liquid system. The ionic liquid system is composed of urea and choline chloride. The weight ratio of choline chloride to urea is 1:1. In the ionic liquid system, copper, indium, The contents and sources of gallium and selenium ions are shown in Table 2. The electrochemical deposition setup consists of a platinum sheet as the anode, a platinum wire as the reference electrode, and a power supply that provides reverse pulses. Electrochemical deposition is controlled by voltage, and the voltage and corresponding current density changes are measured and recorded at the same time.

The surface morphology of the CIGS prefabricated layer prepared according to the method of this embodiment is scanned by an electron microscope. As shown in Figure 5, there is no spherical structure on the CIGS surface, and the energy dispersive X-ray energy spectrum shows that the content of selenium is 50.8%, and the overall composition conforms to copper InGaSe prefab layer requirements.

comparative example

Comparative example 1

According to the method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition in Example 1. The difference from Example 1 is that the electrochemical deposition is a constant current, the current density of constant current deposition and the corresponding voltage change are shown in Figure 6, the current density of constant current is shown in Table 1, and the rest of the conditions are the same as in Example 1.

The surface morphology of the CIGS prefabricated layer prepared according to this comparative example is scanned by an electron microscope, as shown in Figure 7, the CIGS surface is full of many spherical structures, and the X-ray energy spectrum obtained from the spherical shape shows that the content of selenium is 98%. The next structure has a selenium content of 44%, and other components include copper, indium and gallium.

Comparative example 2

According to the method for preparing the copper indium gallium selenide prefabricated layer by electrochemical deposition in Example 2. The difference from Example 2 is that the electrochemical deposition is a constant voltage, the voltage of the constant voltage and the corresponding current density change are shown in Figure 8, the voltage of the constant voltage deposition is shown in Table 1, and the rest of the conditions are the same as in Example 2.

The surface morphology of the CIGS prefabricated layer prepared according to this comparative example is scanned by an electron microscope. As shown in Figure 9, the CIGS surface is full of many spherical structures, and the X-ray energy spectrum obtained from the spherical shape shows that the content of selenium is 86%. The next structure has a selenium content of 38%, and other components include copper, indium and gallium.

Table 1 embodiment and the pulse wave used by comparative examples

Table 2 The content and source of copper, indium, gallium and selenium in the electrochemical deposition solution

Claims (12)

1. A method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition, comprising, in an electrodeposition solution, adopting a current control pulse or a voltage control pulse to obtain a copper indium gallium selenide prefabricated layer by electrodepositing on a cathode substrate, characterized in that : The current control pulse or the voltage control pulse includes a forward pulse period in which the current and voltage both reach negative values on the deposition surface and a reverse pulse period in which the current and voltage both reach positive values on the deposition surface. 2. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 1, characterized in that: the electrodeposition solution is an ionic liquid system. 3. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 1, wherein the pulse condition of the current control pulse is: the working time of the forward pulse period is 3 milliseconds to 1 second, The current density is -0.05ASD～-5ASD; the working time in the reverse pulse period is 1 millisecond to 0.5 seconds, and the current density is 0.1ASD～20ASD. 4. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 1, wherein the pulse condition of the voltage control pulse is: the working time of the forward pulse period is 3 milliseconds to 1 second, The voltage is -0.5V～-8.0V; the working time in the reverse pulse period is 1 millisecond to 0.5 seconds, and the voltage is 0.1V～5.0V. 5. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 1, wherein the concentrations of copper, indium, gallium, and selenium ions in the electrodeposition solution are respectively 0.1mM-50mM, 0.1mM mM-60mM, 0.1mM-80mM, 0.1mM-50mM. 6. the method for preparing copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 2, is characterized in that, the solvent of described ionic liquid system is made up of choline chloride and urea, and the weight of choline chloride and urea The ratio is 1 : 0.5-5. 7. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 6, wherein the weight ratio of choline chloride to urea is 1:2. 8. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 5, wherein all or part of the copper ions in the electrodeposition solution enter the electrodeposition solution after being oxidized by the anode. 9. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 5, wherein all or part of the gallium ions in the electrodeposition solution enter the electrodeposition solution after being oxidized by the anode. 10. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 5, wherein all or part of the indium ions in the electrodeposition solution enter the electrodeposition solution after being oxidized by the anode. 11. The method for preparing a copper indium gallium selenide prefabricated layer by electrochemical deposition according to claim 5, wherein all or part of the selenium ions in the electrodeposition solution enter the electrodeposition solution after being oxidized by the anode. 12. The copper indium gallium selenium prefabricated layer prepared by any electrochemical deposition method according to claims 1 to 11, characterized in that: the thickness of the prefabricated layer deposited by using the reverse pulse is 20% of the thickness of the overall prefabricated layer above.

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