CN108847428B - A kind of solar cell based on silicon nanowire array and preparation method thereof - Google Patents

Abstract

The invention relates to a solar cell based on a silicon nanowire array and a preparation method thereof, wherein the solar cell based on the silicon nanowire array comprises a back electrode, a back passivation layer, an N-type monocrystalline silicon piece, the silicon nanowire array, an upper surface passivation layer, a P3 HT/copper phthalocyanine composite layer, a PEDOT (PSS) layer and a front gate electrode from bottom to top, wherein the PEDOT (PSS) layer contains magnesium elements, and the solar cell based on the silicon nanowire array has excellent photoelectric conversion efficiency by optimizing the structure of the solar cell based on the silicon nanowire array and the specific process parameters of each layer.

Description

A kind of solar cell based on silicon nanowire array and preparation method thereof

technical field

The invention relates to the technical field of solar cells, in particular to a solar cell based on a silicon nanowire array and a preparation method thereof.

Background technique

Monocrystalline silicon solar cells are too expensive to be widely used, and although organic solar cells are low in cost, the efficiency of organic solar cells is much lower than that of inorganic solar cells and cannot be widely used. On this basis, people are paying more and more attention to the development process of organic-inorganic hybrid solar cells. Organic-inorganic hybrid solar cells can combine the advantages of organic materials and inorganic materials, avoid their respective defects, and obtain higher photoelectric conversion. efficiency. The photoelectric conversion efficiency of the existing Si/PEDOT:PSS organic-inorganic hybrid solar cell is about 10%, and the internal structure of the organic-inorganic hybrid solar cell needs to be further improved to improve its photoelectric conversion efficiency.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art, and to provide a solar cell based on a silicon nanowire array and a preparation method thereof.

In order to achieve the above purpose, a method for preparing a solar cell based on a silicon nanowire array proposed by the present invention includes the following steps:

1) Cleaning of N-type silicon wafers;

2) Prepare a silicon nanowire array on the surface of an N-type silicon wafer;

3) methylating the N-type silicon wafer obtained in step 2;

4) Next, spin-coat an organic solution containing aluminum diisopropoxide and zirconium isopropoxide on the upper surface of the N-type silicon wafer, and perform heat treatment to further passivate the upper surface of the N-type silicon wafer ;

5) Preparation of P3HT/copper phthalocyanine composite layer: spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating on the front of the N-type silicon wafer obtained in step 4 in turn P3HT solution, followed by a first annealing treatment to form the P3HT/copper phthalocyanine composite layer;

6) Preparation of PEDOT:PSS layer: add a certain amount of magnesium chloride to the PEDOT:PSS aqueous solution to form a PEDOT:PSS mixed solution, spin-coat the PEDOT:PSS mixed solution on the front of the N-type silicon wafer obtained in the step 5 solution, and carry out a second annealing treatment to form the PEDOT:PSS modified layer;

7) A thin layer of aluminum oxide is prepared by atomic layer deposition on the back of the N-type silicon wafer obtained in the step 6, wherein the deposition rate of aluminum oxide is 1-2 angstroms/cycle, and the number of deposition cycles is 3 -5;

8) Preparation of front gate electrode;

9) Preparation of back electrode.

In the above method for preparing a solar cell based on a silicon nanowire array, further, in the step (2), a silicon nanowire array is prepared on the surface of an N-type silicon wafer by wet etching or dry etching, and the The length of a single silicon nanowire in the silicon nanowire array is 1-1.5 microns, the diameter of the silicon nanowires is 100-400 nanometers, and the spacing between adjacent silicon nanowires is 200-600 nanometers.

In the above-mentioned preparation method of a solar cell based on a silicon nanowire array, further, in the step (3), the N-type silicon wafer obtained in the step (2) is first immersed in a chlorobenzene solution of saturated phosphorus pentachloride, Soak at 120°C for 1-2 hours, then take out the N-type silicon wafer from the saturated phosphorus pentachloride chlorobenzene solution, and then place the N-type silicon wafer in a 1 mol/L methylmagnesium chloride solution in tetrahydrofuran, Soaking at 85° C. for 6-9 hours to form Si-CH ₃ bonds on the surface of the N-type silicon wafer to passivate the N-type silicon wafer.

The above method for preparing a solar cell based on a silicon nanowire array, further, in the step (4), the ethyl ethyl acetoacetate containing aluminum diisopropoxide and zirconium isopropoxide in the organic solution The concentration of aluminum diisopropoxide acetoacetate is 0.3-0.9mg/ml, the concentration of zirconium isopropoxide is 0.3-0.9mg/ml, the rotating speed of spin coating is 4000-5000 rev/min, and the time of spin coating is 1-3 minutes, the temperature of the heat treatment is 200-300° C., and the time of the heat treatment is 15-30 minutes.

The above method for preparing a solar cell based on a silicon nanowire array, further, in the step (5), the concentration of the P3HT solution is 0.5-1 mg/ml, and the rotation speed of each spin coating of the P3HT solution is 1000 -2000 r/min, the time for each spin coating of the P3HT solution is 2-4 minutes, the rate of each thermal evaporation of copper phthalocyanine is 1-2 angstroms/second, and the The time is 3-6 seconds, the annealing temperature of the first annealing treatment is 130-160° C., and the annealing time of the first annealing treatment is 20-40 minutes.

The above-mentioned preparation method of a solar cell based on a silicon nanowire array, further, in the step (6), the concentration of magnesium chloride in the PEDOT:PSS mixed solution is 0.05-0.5mg/ml, and the PEDOT:PSS is spin-coated The rotating speed of the mixed solution is 2000-3000 rpm, the time for spin coating the PEDOT:PSS mixed solution is 1-5 minutes, and the annealing temperature of the second annealing treatment is 110-130° C. The annealing time of the annealing treatment is 15-30 minutes.

The above-mentioned preparation method of a solar cell based on a silicon nanowire array, further, in the step (8), the front grid electrode is formed by thermal evaporation of metallic silver, and the thickness of the front grid electrode is 150-200 nanometers .

In the above-mentioned preparation method of a solar cell based on a silicon nanowire array, further, in the step (9), the back electrode is formed by thermal evaporation of metal aluminum, and the thickness of the back electrode is 200-300 nanometers.

The present invention also provides a solar cell based on a silicon nanowire array, which is prepared and formed by the above method.

Compared with the prior art, the present invention has the following advantages:

In the preparation process of the solar cell based on the silicon nanowire array of the present invention, methylation treatment is firstly performed to passivate the silicon surface, and then an organic solution containing aluminum diisopropoxide ethyl acetoacetate and zirconium isopropoxide is spin-coated, The silicon surface is further passivated by heat treatment, and the defect states on the silicon surface are effectively reduced by a two-step passivation process; the P3HT/copper phthalocyanine composite layer is first formed on the surface of the silicon nanowire array, and then the PEDOT:PSS layer is formed to obtain high-efficiency. The high-quality organic composite film can effectively prevent the top of the silicon nanowire from being exposed to the PEDOT:PSS layer. The ultra-thin P3HT/copper phthalocyanine composite layer improves the contact barrier between the silicon nanowire and the PEDOT:PSS layer. At the same time, the PEDOT: The PSS layer contains magnesium element to further improve the built-in electric field, and an ultra-thin aluminum oxide thin layer is prepared on the back of the N-type silicon wafer, which effectively passivates the back of the silicon wafer. Photoelectric conversion efficiency of silicon nanowire array-based solar cells.

Description of drawings

FIG. 1 is a schematic structural diagram of a solar cell based on a silicon nanowire array of the present invention.

Detailed ways

As shown in FIG. 1 , the present invention proposes a solar cell based on a silicon nanowire array. The solar cell based on a silicon nanowire array includes a back electrode 1 , a back passivation layer 2 , and an N-type single crystal silicon wafer from bottom to top. 3. Silicon nanowire array 4 , upper surface passivation layer 5 , P3HT/copper phthalocyanine composite layer 6 , PEDOT:PSS layer 7 and front gate electrode 8 .

The present invention also proposes a method for preparing the above-mentioned solar cell based on the silicon nanowire array, comprising the following steps:

1) Cleaning of N-type silicon wafers;

2) Prepare a silicon nanowire array on the surface of an N-type silicon wafer, and prepare a silicon nanowire array on the surface of the N-type silicon wafer by wet etching or dry etching. A single silicon nanowire in the silicon nanowire array The length of the silicon nanowires is 1-1.5 microns, the diameter of the silicon nanowires is 100-400 nanometers, and the spacing between adjacent silicon nanowires is 200-600 nanometers;

3) The N-type silicon wafer obtained in the step 2 is subjected to methylation treatment, and the specific steps are as follows: first, the N-type silicon wafer obtained in the step (2) is immersed in a chlorobenzene solution of saturated phosphorus pentachloride, and the temperature is 120 ° C. Soak for 1-2 hours, then the N-type silicon wafer is taken out from the saturated phosphorus pentachloride chlorobenzene solution, and then the N-type silicon wafer is placed in a 1 mol/L tetrahydrofuran solution of methylmagnesium chloride, at 85 Soaking at ℃ for 6-9 hours to form Si-CH ₃ bonds on the surface of the N-type silicon wafer to passivate the N-type silicon wafer;

4) Next, spin-coat an organic solution containing aluminum diisopropoxide and zirconium isopropoxide on the upper surface of the N-type silicon wafer, and perform heat treatment to further passivate the upper surface of the N-type silicon wafer , wherein the concentration of the aluminum ethyl acetoacetate diisopropoxide in the organic solution containing ethyl acetoacetate aluminum diisopropoxide and zirconium isopropoxide is 0.3-0.9 mg/ml, and the isopropanol The concentration of zirconium is 0.3-0.9mg/ml, the rotation speed of spin coating is 4000-5000 rpm, the time of spin coating is 1-3 minutes, the temperature of the heat treatment is 200-300°C, and the time of the heat treatment is 15 -30 minutes;

5) Preparation of P3HT/copper phthalocyanine composite layer: spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating on the front of the N-type silicon wafer obtained in step 4 in turn P3HT solution, followed by a first annealing treatment to form the P3HT/copper phthalocyanine composite layer, wherein the concentration of the P3HT solution is 0.5-1 mg/ml, and the rotation speed of each spin coating of the P3HT solution is 1000 -2000 r/min, the time for each spin coating of the P3HT solution is 2-4 minutes, the rate of each thermal evaporation of copper phthalocyanine is 1-2 angstroms/second, and the The time is 3-6 seconds, the annealing temperature of the first annealing treatment is 130-160° C., and the annealing time of the first annealing treatment is 20-40 minutes;

6) Preparation of PEDOT:PSS layer: add a certain amount of magnesium chloride to the PEDOT:PSS aqueous solution to form a PEDOT:PSS mixed solution, spin-coat the PEDOT:PSS mixed solution on the front of the N-type silicon wafer obtained in the step 5 solution, and perform a second annealing treatment to form the PEDOT:PSS modified layer, wherein the concentration of magnesium chloride in the PEDOT:PSS mixed solution is 0.05-0.5mg/ml, and the PEDOT:PSS mixed solution is spin-coated The rotating speed is 2000-3000 rpm, the time for spin coating the PEDOT:PSS mixed solution is 1-5 minutes, the annealing temperature of the second annealing treatment is 110-130 ° C, and the second annealing treatment The annealing time is 15-30 minutes;

7) A thin layer of aluminum oxide is prepared by atomic layer deposition on the back of the N-type silicon wafer obtained in the step 6, wherein the deposition rate of aluminum oxide is 1-2 angstroms/cycle, and the number of deposition cycles is 3 -5;

8) Preparation of front grid electrode, the front grid electrode is formed by thermal evaporation of metallic silver, and the thickness of the front grid electrode is 150-200 nanometers;

9) Preparation of the back electrode, the back electrode is formed by thermally evaporating metal aluminum, and the thickness of the back electrode is 200-300 nanometers.

Example 1:

The present invention also proposes a method for preparing the above-mentioned solar cell based on the silicon nanowire array, comprising the following steps:

1) Cleaning of N-type silicon wafers;

2) A silicon nanowire array is prepared on the surface of an N-type silicon wafer, and a silicon nanowire array is prepared on the surface of the N-type silicon wafer by wet etching, and the length of a single silicon nanowire in the silicon nanowire array is 1.2 μm , the diameter of the silicon nanowires is 300 nanometers, and the spacing between adjacent silicon nanowires is 400 nanometers;

3) The N-type silicon wafer obtained in the step 2 is subjected to methylation treatment, and the specific steps are as follows: first, the N-type silicon wafer obtained in the step (2) is immersed in a chlorobenzene solution of saturated phosphorus pentachloride, and the temperature is 120 ° C. Soak for 1.5 hours, then the N-type silicon wafer is taken out from the saturated phosphorus pentachloride chlorobenzene solution, and then the N-type silicon wafer is placed in a 1 mol/L methylmagnesium chloride solution in tetrahydrofuran at 85 ° C. Soaking for 8 hours to form Si _- CH bonds on the surface of the N-type silicon wafer to passivate the N-type silicon wafer;

4) Next, spin-coat an organic solution containing aluminum diisopropoxide and zirconium isopropoxide on the upper surface of the N-type silicon wafer, and perform heat treatment to further passivate the upper surface of the N-type silicon wafer , wherein the concentration of the aluminum diisopropoxide ethyl acetoacetate in the organic solution containing aluminum diisopropoxide ethyl acetoacetate and zirconium isopropoxide is 0.6 mg/ml, and the concentration of the zirconium isopropoxide is 0.6 mg/ml. The concentration is 0.6 mg/ml, the rotational speed of the spin coating is 4500 rpm, the spin coating time is 2 minutes, the temperature of the heat treatment is 260°C, and the time of the heat treatment is 25 minutes;

5) Preparation of P3HT/copper phthalocyanine composite layer: spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating on the front of the N-type silicon wafer obtained in step 4 in turn P3HT solution, followed by a first annealing treatment to form the P3HT/copper phthalocyanine composite layer, wherein the concentration of the P3HT solution is 0.7 mg/ml, and the rotation speed of each spin coating of the P3HT solution is 1800 rpm /min, the time for each spin coating of the P3HT solution was 3 minutes, the rate of each thermal evaporation of copper phthalocyanine was 1.5 angstroms/sec, and the time for each thermal evaporation of copper phthalocyanine was 4 seconds. The annealing temperature of the first annealing treatment is 140°C, and the annealing time of the first annealing treatment is 30 minutes;

6) Preparation of PEDOT:PSS layer: add a certain amount of magnesium chloride to the PEDOT:PSS aqueous solution to form a PEDOT:PSS mixed solution, spin-coat the PEDOT:PSS mixed solution on the front of the N-type silicon wafer obtained in the step 5 solution, and carry out a second annealing treatment to form the PEDOT:PSS modified layer, wherein the concentration of magnesium chloride in the PEDOT:PSS mixed solution is 0.2 mg/ml, and the rotating speed of the spin coating the PEDOT:PSS mixed solution is 2500 rpm, the time for spin coating the PEDOT:PSS mixed solution is 3 minutes, the annealing temperature of the second annealing treatment is 120°C, and the annealing time of the second annealing treatment is 20 minutes;

7) A thin layer of aluminum oxide is prepared by atomic layer deposition on the back of the N-type silicon wafer obtained in the step 6, wherein the rate of deposition of aluminum oxide is 1 angstrom/cycle, and the number of cycles of deposition is 5;

8) Preparation of front grid electrode, the front grid electrode is formed by thermal evaporation of metallic silver, and the thickness of the front grid electrode is 180 nanometers;

9) Preparation of the back electrode, the back electrode is formed by thermally evaporating metal aluminum, and the thickness of the back electrode is 220 nanometers.

The open-circuit voltage of the silicon nanowire array-based solar cell prepared by the above method is 0.61V, the short-circuit current is 33.6mA/cm ² , the fill factor is 0.74, and the photoelectric conversion efficiency is 15.17%.

Example 2

The present invention also proposes a method for preparing the above-mentioned solar cell based on the silicon nanowire array, comprising the following steps:

1) Cleaning of N-type silicon wafers;

2) Prepare a silicon nanowire array on the surface of an N-type silicon wafer, and prepare a silicon nanowire array on the surface of the N-type silicon wafer by wet etching or dry etching. A single silicon nanowire in the silicon nanowire array The length of the silicon nanowires is 1 micron, the diameter of the silicon nanowires is 200 nanometers, and the spacing between adjacent silicon nanowires is 300 nanometers;

3) The N-type silicon wafer obtained in the step 2 is subjected to methylation treatment, and the specific steps are as follows: first, the N-type silicon wafer obtained in the step (2) is immersed in a chlorobenzene solution of saturated phosphorus pentachloride, and the temperature is 120 ° C. Soak for 1 hour, then take out the N-type silicon wafer from the saturated phosphorus pentachloride chlorobenzene solution, then place the N-type silicon wafer in a 1 mol/L methylmagnesium chloride solution in tetrahydrofuran at 85°C Soaking for 6 hours to form Si-CH ₃ bonds on the surface of the N-type silicon wafer to passivate the N-type silicon wafer;

4) Next, spin-coat an organic solution containing aluminum diisopropoxide and zirconium isopropoxide on the upper surface of the N-type silicon wafer, and perform heat treatment to further passivate the upper surface of the N-type silicon wafer , wherein the concentration of the aluminum diisopropoxide ethyl acetoacetate in the organic solution containing aluminum diisopropoxide ethyl acetoacetate and zirconium isopropoxide is 0.8 mg/ml, and the concentration of the zirconium isopropoxide is 0.8 mg/ml. The concentration is 0.4 mg/ml, the rotational speed of the spin coating is 4000 rpm, the spin coating time is 3 minutes, the temperature of the heat treatment is 200°C, and the time of the heat treatment is 30 minutes;

5) Preparation of P3HT/copper phthalocyanine composite layer: spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating on the front of the N-type silicon wafer obtained in step 4 in turn P3HT solution, followed by a first annealing treatment to form the P3HT/copper phthalocyanine composite layer, wherein the concentration of the P3HT solution is 1 mg/ml, and the rotation speed of each spin coating of the P3HT solution is 2000 rpm/ minutes, the time for each spin coating of the P3HT solution was 2 minutes, the rate of each thermal evaporation of copper phthalocyanine was 2 angstroms per second, and the time for each thermal evaporation of copper phthalocyanine was 5 seconds. The annealing temperature of the first annealing treatment is 130°C, and the annealing time of the first annealing treatment is 25 minutes;

6) Preparation of PEDOT:PSS layer: add a certain amount of magnesium chloride to the PEDOT:PSS aqueous solution to form a PEDOT:PSS mixed solution, spin-coat the PEDOT:PSS mixed solution on the front of the N-type silicon wafer obtained in the step 5 solution, and carry out a second annealing treatment to form the PEDOT:PSS modified layer, wherein the concentration of magnesium chloride in the PEDOT:PSS mixed solution is 0.05mg/ml, and the rotating speed of the PEDOT:PSS mixed solution spin coating is 2000 rpm, the time for spin coating the PEDOT:PSS mixed solution is 4 minutes, the annealing temperature of the second annealing treatment is 110°C, and the annealing time of the second annealing treatment is 30 minutes;

7) A thin layer of aluminum oxide is prepared by atomic layer deposition on the back of the N-type silicon wafer obtained in the step 6, wherein the rate of deposition of aluminum oxide is 2 angstroms/cycle, and the number of cycles of deposition is 4;

8) Preparation of front grid electrode, the front grid electrode is formed by thermal evaporation of metallic silver, and the thickness of the front grid electrode is 200 nanometers;

9) Preparation of the back electrode, the back electrode is formed by thermally evaporating metal aluminum, and the thickness of the back electrode is 300 nanometers.

The open-circuit voltage of the silicon nanowire array-based solar cell prepared by the above method is 0.6V, the short-circuit current is 32.3mA/cm ² , the fill factor is 0.71, and the photoelectric conversion efficiency is 13.76%.

The above are the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made, and these improvements and modifications may also be regarded as It is the protection scope of the present invention.

Claims (7)

1. a preparation method of solar cell based on silicon nanowire array, is characterized in that: comprise the following steps: 1) Cleaning of N-type silicon wafers; 2) Prepare a silicon nanowire array on the surface of an N-type silicon wafer; 3) methylating the N-type silicon wafer obtained in step 2; 4) Next, spin-coat an organic solution containing aluminum diisopropoxide and zirconium isopropoxide on the upper surface of the N-type silicon wafer, and perform heat treatment to further passivate the upper surface of the N-type silicon wafer ; 5) Preparation of P3HT/copper phthalocyanine composite layer: spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating P3HT solution, thermally evaporated copper phthalocyanine, spin-coating on the front of the N-type silicon wafer obtained in step 4 in turn P3HT solution, followed by a first annealing treatment to form the P3HT/copper phthalocyanine composite layer; 6) Preparation of PEDOT:PSS layer: add a certain amount of magnesium chloride to the PEDOT:PSS aqueous solution to form a PEDOT:PSS mixed solution, spin-coat the PEDOT:PSS mixed solution on the front of the N-type silicon wafer obtained in the step 5 solution, and carry out a second annealing treatment to form the PEDOT:PSS modified layer; 7) A thin layer of aluminum oxide is prepared by atomic layer deposition on the back of the N-type silicon wafer obtained in the step 6, wherein the deposition rate of aluminum oxide is 1-2 angstroms/cycle, and the number of deposition cycles is 3 -5; 8) Preparation of front gate electrode; 9) Preparation of back electrode; Wherein, in the step (5), the concentration of the P3HT solution is 0.5-1 mg/ml, the rotation speed of each spin coating of the P3HT solution is 1000-2000 rpm, and the P3HT solution is spin coated each time The time for each thermal evaporation of copper phthalocyanine is 2-4 minutes, the rate of each thermal evaporation of copper phthalocyanine is 1-2 angstroms per second, and the time for each thermal evaporation of copper phthalocyanine is 3-6 seconds, and the first annealing The annealing temperature of the treatment is 130-160° C., and the annealing time of the first annealing treatment is 20-40 minutes; Wherein, in the step (6), the concentration of magnesium chloride in the PEDOT:PSS mixed solution is 0.05-0.5mg/ml, and the rotating speed of the PEDOT:PSS mixed solution spin coating is 2000-3000 rev/min, and the spin coating The time of the PEDOT:PSS mixed solution is 1-5 minutes, the annealing temperature of the second annealing treatment is 110-130° C., and the annealing time of the second annealing treatment is 15-30 minutes. 2 . The method for preparing a solar cell based on a silicon nanowire array according to claim 1 , wherein in the step (2), wet etching or dry etching is performed on the surface of the N-type silicon wafer. 3 . A silicon nanowire array is prepared on the surface, the length of a single silicon nanowire in the silicon nanowire array is 1-1.5 microns, the diameter of the silicon nanowire is 100-400 nanometers, and the spacing between adjacent silicon nanowires is 200- 600 nm. 3. The method for preparing a solar cell based on a silicon nanowire array according to claim 1, wherein in the step (3), the N-type silicon wafer obtained in the step (2) is first immersed in saturated pentachloride In the chlorobenzene solution of phosphorus pentachloride, soak it at 120 ° C for 1-2 hours, then take out the N-type silicon wafer from the saturated phosphorus pentachloride chlorobenzene solution, and then place the N-type silicon wafer at 1mol/ In the tetrahydrofuran solution of L methylmagnesium chloride, soak at 85° C. for 6-9 hours to form Si-CH ₃ bonds on the surface of the N-type silicon wafer, so as to passivate the N-type silicon wafer. 4 . The method for preparing a solar cell based on a silicon nanowire array according to claim 1 , wherein in the step (4), the method containing ethyl acetoacetate aluminum diisopropoxide and isopropanol In the organic solution of zirconium, the concentration of the aluminum ethyl acetoacetate diisopropoxide is 0.3-0.9mg/ml, the concentration of the zirconium isopropoxide is 0.3-0.9mg/ml, and the rotating speed of the spin coating is 4000-5000 rev/min, the spin coating time is 1-3 minutes, the heat treatment temperature is 200-300°C, and the heat treatment time is 15-30 minutes. 5 . The method for preparing a solar cell based on a silicon nanowire array according to claim 1 , wherein in the step (8), the front-side grid electrode is formed by thermally evaporating metallic silver, and the front-side grid electrode is formed. 6 . The thickness of the gate electrode is 150-200 nm. 6 . The method for preparing a solar cell based on a silicon nanowire array according to claim 1 , wherein in the step (9), the back electrode is formed by thermally evaporating metal aluminum. 7 . The thickness is 200-300 nm. 7 . A solar cell based on a silicon nanowire array, characterized in that, it is formed by the method of any one of claims 1-6 .

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