A copper-indium-gallium-sulfur micro-nano secondary array, a preparation method and application thereof

Abstract

The application discloses a copper-indium-gallium-sulfur micro-nano secondary array and a preparation method and application thereof. The micro-nano secondary array is composed of regularly arranged micro semiconductor spherical caps grown on a substrate and semiconductor nanosheets on the surface of the spherical caps. The micro-nano secondary array has better light absorption performance than similar films due to the special morphology. In addition, the nanosheets are regularly arranged on the surface of the micro spherical caps, so that the light incident from various angles can be absorbed while the sensitivity to the light incident angle is reduced. When the array is applied in the photovoltaic field, the absorption of sunlight can be effectively increased, and the photogenerated carrier recombination rate and the use cost of the solar cell can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of solar photovoltaic cell technology, specifically relating to a copper indium gallium sulfide micro / nano secondary array, its fabrication method, and its application. Background Technology

[0002] Metal chalcogenide semiconductor materials have attracted much attention in the fields of optoelectronics, photocatalysis and sensors due to their excellent physical and chemical properties. At the same time, with the development of nanotechnology and the improvement of nanomaterial synthesis processes, metal chalcogenide semiconductors with different morphologies, such as nanowires, nanosheets and nanorods, are constantly being synthesized and applied.

[0003] Chinese patent CN201310733812.2 discloses a method for preparing a copper indium sulfide selenide (CIGS) thin film based on nanoparticles for solar cells. This invention employs magnetron sputtering to sequentially deposit a back electrode and a CIGS absorber layer on a substrate, followed by selenization treatment to obtain the CIGS absorber layer. A CdS buffer layer, an intrinsic zinc oxide high-resistivity layer, and an indium tin oxide (ITO) thin film low-resistivity layer are then sequentially prepared outside the absorber layer to obtain the CIGS thin film for solar cells. This invention is simple to operate, does not introduce other impurities, and is environmentally friendly, making it suitable for industrial production; however, the preparation of the absorber layer requires high temperature and voltage control, which correspondingly increases the synthesis cost.

[0004] Chinese patent CN109589991A discloses a zinc-indium-sulfur (ZIN) / copper-indium-sulfur (CIS) two-dimensional heterojunction photocatalyst, its preparation method, and its applications. The invention first prepares a suspension by dissolving a zinc source compound, an indium source compound, and a sulfur source compound in water. This suspension is then reacted at 100℃–250℃ for at least 10 hours. The product is collected by centrifugation, washed, and dried to obtain a ZnIn2S4 photocatalyst. Next, the copper source compound, indium source compound, sulfur source compound, and the ZnIn2S4 photocatalyst are dispersed in ethylene glycol to prepare a suspension. This suspension is then reacted at 100℃–250℃ for at least 10 hours. The product is collected by centrifugation, washed, and dried to obtain a ZnIn2S4 / CuInS2 two-dimensional heterojunction photocatalyst. This synthesis method is simple, and the obtained two-dimensional heterojunction has good crystallinity and high purity. However, the product obtained after centrifugation is a powder, which has weaker adhesion to the substrate compared to materials grown directly on the substrate, making it unsuitable for direct application in the photovoltaic field.

[0005] Chinese patent CN105118877B discloses a method for preparing copper indium gallium sulfide selenide (CIGS) thin film materials. This invention prepares a pre-layer CIGS on a solar cell substrate via reactive sputtering, followed by selenization annealing under specific conditions to obtain the CIGS thin film material. This reactive sputtering pre-layer followed by selenization method allows for precise control of the stoichiometry of elements, film thickness, and compositional distribution. The resulting film exhibits high density and minimal volume expansion, effectively addressing existing methods for preparing CIGS semiconductor thin films, which suffer from challenges such as poor composition control, uneven uniformity, numerous surface defects, and the formation of undesirable impurity phases. However, the selenization annealing process in this invention requires high temperatures, increasing the material synthesis cost. Furthermore, binary impurity phases are easily formed on the film surface after selenization.

[0006] Chinese patent CN110364422B discloses a copper indium gallium sulfide (CIGS) two-dimensional nanostructure array, its preparation method, and its application. This invention synthesizes CuXS nanosheet clusters via a hydrothermal method, and then synthesizes a CIGS two-dimensional nanostructure array by combining continuous ion layer adsorption (SILAR) with annealing. The two-dimensional nanostructure array synthesized by this method exhibits orderly arrangement, good periodicity, and excellent light absorption performance. However, the material in this patent is deposited directly on the substrate via a hydrothermal reaction, resulting in a much weaker bond with the substrate compared to materials grown directly on the substrate in situ. The SILAR synthesis requires repeating the following four steps: 1) Immersing the substrate in an ion precursor solution of the target compound to adsorb cations; 2) Removing excess ions not tightly adsorbed on the substrate surface with deionized water (DIW); 3) Immersing the substrate in an anion precursor solution of the target compound, where the anions and cations react to obtain the target compound; 4) Removing unreacted ions from the surface with deionized water. The process is very complicated and time-consuming. Moreover, due to the inability to precisely control the soaking time and the influence of changes in the concentration of the precursor solution, the deposited films generally have uneven particle size. At the same time, annealing requires a high temperature, and the annealing temperature also needs to be constantly explored, which undoubtedly increases the synthesis cost of the material.

[0007] R. Inguanta et al. prepared CIGS nanowire arrays using alumina as a template via constant voltage electrodeposition and conducted photoelectrochemical tests and bandgap analysis. The results showed that, due to the presence of a cathode photocurrent and a CIGS bandgap of 1.55 eV, the nanowire array could be used for nanowire solar cells, and its bandgap was close to the optimal bandgap of 1.45 eV for solar cells. However, the CIGS nanowires prepared by this method are amorphous, meaning that their photoelectric conversion efficiency would still be reduced during application due to their inherent crystal structure and defects.

[0008] Existing literature indicates that nanomaterials applied in the photovoltaic field can increase light absorption and improve photoelectric conversion efficiency. While one-dimensional nanoarrays can be prepared using template-based electrochemical methods, and two-dimensional photocatalyst powders can be synthesized via hydrothermal methods, a simple, low-cost method suitable for large-area nanomaterial preparation still lacks a suitable approach. Furthermore, currently fabricated two-dimensional nanofilm solar cells require constant repositioning of the solar panel to adapt to changes in sunlight exposure, which can increase the cost of solar cells. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a copper indium gallium sulfide micro / nano secondary array, its fabrication method, and its applications. This micro / nano secondary array can effectively solve problems in photovoltaic applications such as high recombination rate of photogenerated carriers in solar cells, cumbersome and time-consuming fabrication process, high fabrication cost, ineffective utilization of sunlight, and sensitivity to the incident angle of light.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: A copper indium gallium sulfide (CIGS) micro / nano secondary array is disclosed, comprising regularly arranged micrometer-scale semiconductor spherical caps grown on a substrate and semiconductor nanosheets on the surface of the caps. The secondary array described in this invention exhibits superior photogenerated carrier separation efficiency and light absorption performance compared to CIGS thin films, and can effectively improve the performance of solar cells in photovoltaic applications.

[0011] The aforementioned copper indium gallium sulfide micro / nano secondary array uses a copper indium gallium sulfide semiconductor with a single-crystal structure.

[0012] Specifically, in the aforementioned micro-nano secondary array, the diameter of the spherical cap is 0.5-100μm, and the thickness of the nanosheets is 0.1nm-1μm.

[0013] This invention provides a method for fabricating the above-mentioned copper indium gallium sulfide micro / nano secondary array, which includes the following steps: 1) Place the clean substrate at the bottom of the reactor and add the first precursor solution; after sealing the reactor, heat it at 80-300℃ for 2-50 hours. After cleaning and drying, a cuprous sulfide film with a spherical crown-shaped undulating structure will grow on the surface of the substrate. 2) Take out the substrate with the grown cuprous sulfide film and place it at the bottom of another reactor. Add the second precursor solution. After sealing the reactor, heat it at 80℃-200℃ for 2h-50h. After cleaning and drying, copper indium gallium sulfide micro-nano secondary array is obtained.

[0014] Specifically, the ratio of the volume of the first or second precursor liquid to the volume of the reactor is 3-2:5.

[0015] Further, in step 1), the first precursor solution is prepared by dissolving thioacetamide in ethylene glycol, and the concentration of thioacetamide is 0.01-1 mol / L.

[0016] Further, in step 2), the second precursor solution is prepared by dissolving thioacetamide, indium chloride, and gallium chloride in ethylene glycol at a mass ratio of 0.6-1:7:6.

[0017] Specifically, in step 1), the substrate is a copper sheet, or a ceramic, mica, polymer plastic, metal, silicon wafer, glass, or stainless steel sheet with a copper film deposited on its surface; the thickness of the copper film is 50 nm-50 μm. The deposition method includes physical vapor deposition (PVD) or electrochemical deposition; the PPVD method includes sputtering, thermal evaporation, electron beam evaporation, laser beam evaporation, or selenization, etc.; the electrochemical deposition method includes pulsed electrochemical deposition, constant voltage electrochemical deposition, or constant current electrochemical deposition, etc. Conventional techniques in the field can be used for deposition, and will not be described in detail here.

[0018] This invention also provides the application of the above-mentioned copper indium gallium sulfide micro / nano secondary array in the photovoltaic field.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The copper indium gallium sulfide micro / nano secondary array of the present invention is self-grown on copper sheet or copper film, which ensures good electrical contact between the secondary array and the substrate. At the same time, the copper sheet can also be used as an electrode and heat sink for the later solar cell. 2) This invention directly grows single-crystal copper indium gallium sulfide (CIGS) micro / nano secondary arrays on a substrate using a two-step hydrothermal method. Because it is an in-situ growth process following a direct reaction between the precursor solution and the copper substrate or film, the adhesion between the secondary array and the substrate is extremely strong. Specifically, the first hydrothermal reaction involves the release of sulfur from thioacetamide in the precursor solution, which reacts directly with copper on the copper sheet or film to form cuprous sulfide. The second hydrothermal reaction involves the further reaction of cuprous sulfide with In, Ga, and S in the precursor solution to form CuInGaS. Therefore, both steps involve direct reaction between the solution and the substrate, resulting in in-situ growth and a stronger adhesion than materials formed through direct deposition. Furthermore, by adjusting the concentration of the precursor solution, the hydrothermal temperature, and the time in the hydrothermal method, the thickness of the nanosheets and the proportion of constituent elements in the micro / nano secondary array can be controlled, enabling the controlled growth of the micro / nano secondary array. 3) The present invention has the advantages of simple synthesis method, low requirements for synthesis conditions and equipment, low cost, controllable synthesis conditions, and convenient large-scale application of reaction products; 4) In the micro / nano secondary array synthesized in this invention, the nanosheets constituting the nanoarray have a large specific surface area, which can significantly increase light absorption in photovoltaic applications. Simultaneously, in solar cells, light absorption and photogenerated carrier separation occur along two mutually perpendicular directions, effectively solving the problem of photogenerated carrier recombination in solar cells. Furthermore, due to the regular arrangement of the micro / nano secondary array, light incident from all angles can be well absorbed, reducing the sensitivity of the nanofilm to the angle of light incidence. In photovoltaic applications, this avoids the problem of battery performance degradation due to changes in the sun's position, or the need to constantly adjust the solar cell angle according to changes in the illumination angle, leading to increased costs. 5) The micro-nano secondary array synthesized by this invention has an ordered arrangement, good periodicity, and excellent light absorption performance, and can be used to prepare high-efficiency large-area solar cells. Attached Figure Description

[0020] Figure 1 This is a schematic diagram (longitudinal section) of the copper indium gallium sulfide micro / nano secondary array of Example 2; wherein, 1-substrate, 2-copper film, 3-copper indium gallium sulfide nanosheet, 4-micron-sized copper indium gallium sulfide spherical cap; Figure 2 This is a scanning electron microscope image of the cuprous sulfide thin film with a spherical crown-shaped undulating structure in Example 4; Figure 3 This is a scanning electron microscope image of the copper indium gallium sulfide micro / nano secondary array in Example 4. Detailed Implementation

[0021] The specific embodiments of the present invention will be further described in detail below with reference to examples.

[0022] Example 1 A copper indium gallium sulfide micro / nano secondary array, the fabrication method of which includes the following steps: (1) Polish the copper substrate with 0-6 sandpaper, and clean it with alcohol, acetone and deionized water in sequence for 5 minutes. After cleaning, dry it and put it at the bottom of the stainless steel reactor. Dissolve thioacetamide in ethylene glycol (thioacetamide concentration is 0.05mol / L) to obtain the first precursor solution, and pour it into the reactor. The ratio of the volume of the first precursor solution to the volume of the reactor is 3:5. (2) After sealing the reactor, heat it at 80°C for 36 hours. After taking out the copper substrate, cleaning and drying it, a cuprous sulfide film with a spherical crown-shaped undulating structure is grown on the surface of the copper substrate. (3) Place the copper substrate with a copper sulfide film grown in step (2) into the bottom of another reactor. Dissolve thioacetamide, indium chloride and gallium chloride in ethylene glycol in a mass ratio of 0.6:7:6 to obtain a second precursor solution. Pour the solution into the reactor. The ratio of the volume of the second precursor solution to the volume of the reactor is 3:5. (4) After sealing the reactor, heat it at 200°C for 18 hours. Take out the copper substrate, clean and dry it to obtain a copper indium gallium sulfide micro-nano secondary array.

[0023] The fabricated copper indium gallium sulfide (CIGS) micro-nano secondary array consists of regularly arranged micrometer-sized semiconductor spherical caps grown on a substrate, and semiconductor nanosheets on the surface of the caps. The single-crystal CIGS nanosheets are 10 nm thick, and the caps have a diameter of 1 μm. The specific surface area of ​​the fabricated CIGS micro-nano secondary array is significantly larger than that of a CIGS film of the same thickness, resulting in a larger light absorption area and an average light absorption rate of 97%, which is insensitive to the incident angle. Compared to a CIGS film of the same thickness, its light absorption rate is increased by nearly 19%. When the incident light changes from perpendicular to the sample surface to 45° to the sample surface, its absorption rate decreases by only 5.5%. In photovoltaic applications, this structure can effectively reduce the recombination rate of photogenerated carriers.

[0024] Example 2 A copper indium gallium sulfide micro / nano secondary array, the fabrication method of which includes the following steps: (1) After being cleaned sequentially with 1 mol / L NaOH solution and 1 mol / L hydrochloric acid, a Cu film was sputtered onto a silicon wafer substrate that had been ultrasonically cleaned sequentially with anhydrous ethanol and deionized water. The thickness of the Cu film was 50 nm. The silicon wafer with the deposited copper film was placed at the bottom of a stainless steel reactor. Thioacetamide was dissolved in ethylene glycol (thioacetamide concentration was 0.01 mol / L) to obtain the first precursor solution, which was then poured into the reactor. The ratio of the volume of the first precursor solution to the volume of the reactor was 2:5. (2) After sealing the reactor, heat it at 300°C for 5 hours. After taking out the substrate, cleaning and drying it, a cuprous sulfide film with a spherical crown-shaped undulating structure is grown on the surface of the substrate. (3) Place the silicon wafer with a cuprous sulfide film grown in step (2) into the bottom of another reactor. Dissolve thioacetamide, indium chloride and gallium chloride in ethylene glycol in a mass ratio of 1:7:6 to obtain a second precursor solution, and pour it into the reactor. The ratio of the volume of the second precursor solution to the volume of the reactor is 2:5. (4) After sealing the reactor, heat it at 80°C for 50 hours. Then, take out the substrate, clean and dry it to obtain a copper indium gallium sulfide micro-nano secondary array.

[0025] The fabricated copper indium gallium sulfide (CIGS) micro / nano secondary array consists of regularly arranged micrometer-scale semiconductor spherical caps grown on a substrate, and semiconductor nanosheets on the surface of the caps. The single-crystal CIGS nanosheets are 20 nm thick, and the caps have a diameter of 0.5 μm. A schematic diagram is shown below. Figure 1 As shown.

[0026] The fabricated copper indium gallium sulfide (CIGS) micro / nano secondary array exhibits a significantly larger specific surface area compared to a CIGS film of the same thickness. This results in a larger light absorption area, achieving an average light absorption rate of 96.8%, and it remains insensitive to the incident angle of light. Compared to a CIGS film of the same thickness, its light absorption rate increases by nearly 19%. When the incident light changes from perpendicular to the sample surface to at a 45° angle, the absorption rate decreases by only 6%. In photovoltaic applications, this structure can effectively reduce the recombination rate of photogenerated carriers.

[0027] Example 3 A copper indium gallium sulfide micro / nano secondary array, the fabrication method of which includes the following steps: (1) A copper film is deposited on a newly cut mica substrate by electron beam evaporation (the electron beam evaporation can be carried out using conventional techniques in this field, which is not the innovation of this application, so it will not be described in detail here). The thickness of the copper film is 10 μm. The mica sheet with the deposited copper film is placed at the bottom of a stainless steel reactor. Thioacetamide is dissolved in ethylene glycol (thioacetamide concentration is 1 mol / L) to obtain the first precursor solution, which is poured into the reactor. The ratio of the volume of the first precursor solution to the volume of the reactor is 1:2. (2) After sealing the reactor, heat it at 200°C for 20 hours. After taking out the substrate, cleaning and drying it, a cuprous sulfide film with a spherical crown-shaped undulating structure is grown on the surface of the substrate. (3) Place the mica sheet with a copper sulfide film grown in step (2) into the bottom of another reactor. Dissolve thioacetamide, indium chloride and gallium chloride in ethylene glycol at a mass ratio of 0.8:7:6 to obtain a second precursor solution. Pour the solution into the reactor. The ratio of the volume of the second precursor solution to the volume of the reactor is 1:2. (4) After sealing the reactor, heat it at 180°C for 24 hours. Then, take out the substrate, clean and dry it to obtain a copper indium gallium sulfide micro-nano secondary array.

[0028] The fabricated copper indium gallium sulfide (CIGS) micro / nano secondary array consists of regularly arranged micrometer-scale semiconductor spherical caps grown on a substrate, and semiconductor nanosheets on the surface of the caps. The single-crystal CIGS nanosheets are 0.1 nm thick, and the caps have a diameter of 10 μm. A schematic diagram is shown below. Figure 1 As shown.

[0029] The fabricated copper indium gallium sulfide (CIGS) micro / nano secondary array exhibits a significantly larger specific surface area compared to a CIGS film of the same thickness. This results in a larger light absorption area, achieving an average light absorption rate of 98%, and insensitivity to the incident angle. Compared to a CIGS film of the same thickness, its light absorption rate is increased by nearly 20%. When the incident light changes from perpendicular to the sample surface to at a 45° angle, the absorption rate decreases by only 5%. In photovoltaic applications, this structure can effectively reduce the recombination rate of photogenerated carriers.

[0030] Example 4 A copper indium gallium sulfide micro / nano secondary array, the fabrication method of which includes the following steps: (1) A copper film with a thickness of 2 μm was magnetron sputtered on a stainless steel substrate that had been ultrasonically cleaned with anhydrous ethanol and deionized water. The stainless steel substrate with the deposited copper film was placed at the bottom of a stainless steel reactor. Thioacetamide was dissolved in ethylene glycol (thioacetamide concentration was 0.063 mol / L) to obtain the first precursor solution, which was poured into the reactor. The ratio of the volume of the first precursor solution to the volume of the reactor was 1:2. (2) After sealing the reactor, heat it at 200°C for 20 hours. After taking out the substrate, cleaning and drying it, a cuprous sulfide film with a spherical crown-shaped undulating structure is grown on the surface of the substrate. (3) Place the stainless steel sheet with a cuprous sulfide film grown in step (2) into the bottom of another reactor. Dissolve thioacetamide, indium chloride and gallium chloride in ethylene glycol at a mass ratio of 0.8:7:6 to obtain a second precursor solution, and pour it into the reactor. The ratio of the volume of the second precursor solution to the volume of the reactor is 1:2. (4) After sealing the reactor, heat it at 180°C for 24 hours. Then, take out the substrate, clean and dry it to obtain a copper indium gallium sulfide micro-nano secondary array.

[0031] The fabricated copper indium gallium sulfide (CIGS) micro / nano secondary array consists of regularly arranged micrometer-scale semiconductor spherical caps grown on a substrate, and semiconductor nanosheets on the surface of the caps. The single-crystal CIGS nanosheets are 30 nm thick, and the caps have a diameter of 3 μm. A schematic diagram is shown below. Figure 1 As shown.

[0032] Figure 2 Scanning electron microscope (SEM) images of the cuprous sulfide thin film with a spherical crown-like undulating structure in Example 4 are provided. Figure 2 As can be seen, the cuprous sulfide particles are arranged in a spherical crown shape, and this spherical crown structure will help to form the subsequent copper indium gallium sulfide micro-nano secondary array structure.

[0033] Figure 3 Scanning electron microscope (SEM) images of the copper indium gallium sulfide (CIGS) micro / nano secondary array in Example 4 are provided. Figure 3 It can be seen that the micro-nano secondary array is arranged regularly, with the diameter of the spherical cap being about 3 μm and the thickness of the nanosheets being about 30 nm.

[0034] The fabricated copper indium gallium sulfide (CIGS) micro / nano secondary array exhibits a significantly larger specific surface area compared to a CIGS film of the same thickness. This results in a larger light absorption area, achieving an average light absorption rate of 97%, and it is insensitive to the incident angle of light. Compared to a CIGS film of the same thickness, its light absorption rate is increased by nearly 19%. When the incident light changes from perpendicular to the sample surface to 45°, its absorption rate decreases by only 6%. In photovoltaic applications, this structure can effectively reduce the recombination rate of photogenerated carriers.

[0035] Example 5 The fabrication method of the copper indium gallium sulfide micro / nano secondary array in Example 5 is the same as that in Example 4, except that: The substrate in step (1) is glass, and the method for depositing copper film is magnetron sputtering; The heating temperature in step (2) is 100℃, and the heating time is 50h; The heating temperature in step (4) is 80℃ and the heating time is 24h.

[0036] The fabricated copper indium gallium sulfide (CIGS) micro / nano secondary array consists of regularly arranged micrometer-scale semiconductor spherical caps grown on a substrate, and semiconductor nanosheets on the surface of the caps. The single-crystal CIGS nanosheets are 1 μm thick, and the caps have a diameter of 50 μm.

[0037] The fabricated copper indium gallium sulfide (CIGS) two-dimensional nanostructure array exhibits a significantly larger specific surface area compared to a CIGS film of the same thickness. This results in a larger light absorption area, achieving an average light absorption rate of 96.4%, and reducing sensitivity to the incident light angle. Compared to a CIGS film of the same thickness, its light absorption rate increases by nearly 18%. When the incident light is changed from perpendicular to the sample surface to at a 45° angle, the absorption rate decreases by only 6.5%.

[0038] Example 6 The fabrication method of the copper indium gallium sulfide micro / nano secondary array in Example 6 is the same as that in Example 4, except that: The substrate in step (1) is a polymer plastic, and the method for depositing the copper film is thermal evaporation. The heating temperature in step (2) is 80℃, and the heating time is 50h; The heating temperature in step (4) is 150℃ and the heating time is 36h.

[0039] The fabricated copper indium gallium sulfide (CIGS) micro / nano secondary array consists of regularly arranged micrometer-scale semiconductor spherical caps grown on a substrate, and semiconductor nanosheets on the surface of the caps. The single-crystal CIGS nanosheets are 0.8 μm thick, and the caps have a diameter of 100 μm.

[0040] The fabricated copper indium gallium sulfide (CIGS) two-dimensional nanostructure array exhibits a significantly larger specific surface area compared to a CIGS film of the same thickness. This results in a larger light absorption area, achieving an average light absorption rate of 96.6%, and reducing sensitivity to the incident light angle. Compared to a CIGS film of the same thickness, its light absorption rate increases by nearly 18%. When the incident light is changed from perpendicular to the sample surface to at a 45° angle, the absorption rate decreases by only 7%.

[0041] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A copper indium gallium sulfide micro / nano dual-level array, characterized in that, It consists of regularly arranged micron-sized semiconductor spheres grown on a substrate and semiconductor nanosheets on the surface of the spheres; The semiconductor is copper indium gallium sulfide with a single crystal structure; The copper indium gallium sulfide micro / nano secondary array was prepared by the following steps: 1) Place the clean substrate at the bottom of the reactor and add the first precursor solution; after sealing the reactor, heat it at 80-300℃ for 2-50 hours. After cleaning and drying, a cuprous sulfide film with a spherical crown-shaped undulating structure will grow on the surface of the substrate. 2) Take out the substrate with the grown cuprous sulfide film and place it at the bottom of another reactor. Add the second precursor solution. After sealing the reactor, heat it at 80℃-200℃ for 2h-50h. After cleaning and drying, copper indium gallium sulfide micro-nano secondary array is obtained. Step 1) The first precursor solution is prepared by dissolving thioacetamide in ethylene glycol, and the concentration of thioacetamide is 0.01-1 mol / L; Step 2) The second precursor solution is prepared by dissolving thioacetamide, indium chloride and gallium chloride in ethylene glycol in a mass ratio of 0.6-1:7:

6.

2. The copper indium gallium sulfide micro / nano secondary array according to claim 1, characterized in that: In the micro-nano secondary array, the diameter of the spherical cap is 0.5-100μm, and the thickness of the nanosheets is 0.1nm-1μm.

3. A method for fabricating a copper indium gallium sulfide micro / nano secondary array as described in any one of claims 1 to 2, characterized in that, Includes the following steps: 1) Place the clean substrate at the bottom of the reactor and add the first precursor solution; after sealing the reactor, heat it at 80-300℃ for 2-50 hours. After cleaning and drying, a cuprous sulfide film with a spherical crown-shaped undulating structure will grow on the surface of the substrate. 2) Take out the substrate with the grown cuprous sulfide film and place it at the bottom of another reactor. Add the second precursor solution. After sealing the reactor, heat it at 80℃-200℃ for 2h-50h. After cleaning and drying, copper indium gallium sulfide micro-nano secondary array is obtained.

4. The method for fabricating a copper indium gallium sulfide micro / nano secondary array according to claim 3, characterized in that, The ratio of the volume of the first or second precursor liquid to the volume of the reactor is 3-2:

5.

5. The method for fabricating a copper indium gallium sulfide micro / nano secondary array according to claim 3, characterized in that, Step 1) The first precursor solution is prepared by dissolving thioacetamide in ethylene glycol, and the concentration of thioacetamide is 0.01-1 mol / L.

6. The method for fabricating a copper indium gallium sulfide micro / nano secondary array according to claim 3, characterized in that, Step 2) The second precursor solution is prepared by dissolving thioacetamide, indium chloride and gallium chloride in ethylene glycol in a mass ratio of 0.6-1:7:

6.

7. The method for fabricating a copper indium gallium sulfide micro / nano secondary array according to claim 3, characterized in that, Step 1) The substrate is a copper sheet, or a ceramic, mica, polymer plastic, metal, silicon wafer, glass, or stainless steel sheet with a copper film deposited on its surface; the thickness of the copper film is 50nm-50μm.

8. The method for fabricating a copper indium gallium sulfide micro / nano secondary array according to claim 3, characterized in that, The deposition methods include physical vapor deposition or electrochemical deposition; the physical vapor deposition method is sputtering, thermal evaporation, electron beam evaporation, laser beam evaporation or selenization; the electrochemical deposition method is pulsed electrochemical deposition, constant voltage electrochemical deposition or constant current electrochemical deposition.

9. The application of the copper indium gallium sulfide micro / nano secondary array as described in claim 1 or 2 in the photovoltaic field.

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