Metal oxide doped photoelectric conversion material and preparation method thereof

Abstract

The invention belongs to the technical field of photoelectric conversion materials, and provides a metal oxide doped photoelectric conversion material and a preparation method thereof, and the metal oxide doped photoelectric conversion material comprises a cuprous oxide thin film, and acid leaching rice hull ash and vanadium trioxide which are coated on the cuprous oxide thin film and doped with the cuprous oxide thin film. The photoelectric conversion efficiency of the photoelectric conversion material in a high-humidity environment can be better maintained.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic conversion materials, and particularly relates to a metal oxide-doped optoelectronic conversion material and a preparation method thereof. Background Art

[0002] Cuprous oxide is a very important p-type semiconductor material, which has unique electrical, optical and catalytic properties and has wide application value in the fields of photocatalysis, solar cells, gas sensing elements and batteries. Its band gap is about 2.1 eV, enabling it to effectively absorb visible light (wavelength range 390 - 780 nm), thus showing high photo-responsive performance in solar energy conversion and photocatalysis.

[0003] In a high-humidity environment, water molecules easily penetrate into the pores of the cuprous oxide thin film and react with the surface of the cuprous oxide thin film to produce intermediate products such as copper hydroxide. This process will cause damage to the surface structure of the thin film, form a passivation layer, hinder charge transport, and thus reduce the optoelectronic conversion efficiency. Summary of the Invention

[0004] In view of the above problems, the present invention provides a metal oxide-doped optoelectronic conversion material and a preparation method thereof, which can better maintain the optoelectronic conversion efficiency of the obtained optoelectronic conversion material in a high-humidity environment.

[0005] To achieve the above object, in the first aspect, the present invention provides a metal oxide-doped optoelectronic conversion material, including a cuprous oxide thin film and acid-leached rice husk ash and vanadium trioxide coated on the cuprous oxide thin film and doped with the cuprous oxide thin film.

[0006] Further, the doping mass fraction of the acid-leached rice husk ash is 3% - 4%.

[0007] Further, the doping mass fraction of the vanadium trioxide is 2% - 2.5%.

[0008] Further, the preparation method of the acid-leached rice husk ash is as follows:

[0009] A1. Immerse rice husks in a sulfuric acid solution with a mass fraction of 1.5 - 2%, with a solid-liquid ratio of 1:30. After soaking at room temperature for 2 - 2.5 h, filter out, wash with water until neutral, and air-dry naturally to obtain acid-treated rice husks;

[0010] A2. Place the acid-treated rice husks obtained in A1 in a crucible, then put it into a muffle furnace, calcine at 520 - 550 °C for 1.5 - 2 h, take out, and perform steam treatment, that is, expose to 100 °C steam for 45 - 60 min, and then air-dry naturally to obtain acid-leached rice husk ash.

[0011] In a second aspect, the present invention provides a method for preparing the above-mentioned metal oxide-doped optoelectronic conversion material, comprising the following steps:

[0012] S1. After separately grinding vanadium trioxide and acid-leached rice husk ash, vanadium trioxide nanoparticles and acid-leached rice husk ash nanoparticles are obtained, and are put into deionized water according to the doping ratio, a dispersant is added, and ultrasonic treatment is carried out to ensure uniform dispersion, obtaining a mixed suspension;

[0013] S2. The mixed suspension obtained in S1 is uniformly coated on the surface of the cuprous oxide film by spin coating, and the coating thickness is 15-20 μm, so that the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles diffuse into the pores of the cuprous oxide film, and then the water is drained, and then it is placed in a vacuum drying oven (pressure -0.1 MPa, temperature 50-60 °C) for treatment for 3-4 h to ensure that there is no residual solvent in the pores, obtaining a composite coated film;

[0014] S3. The composite coated film obtained in S2 is placed in a tube furnace, and under the protection of an inert gas nitrogen, it is heated to 300-330 °C, kept warm for 1-2 h, and then naturally cooled to room temperature, obtaining the metal oxide-doped optoelectronic conversion material.

[0015] Further, in S1, the particle sizes of the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles are both less than 100 nm.

[0016] Further, in S1, the dispersant includes polyethylene glycol or polyvinylpyrrolidone.

[0017] Further, the sum of the masses of the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles accounts for 5%-6.5% of the mass of the mixed suspension; the mass of the dispersant accounts for 0.15%-0.35% of the mass of the mixed suspension.

[0018] Further, in S1, the frequency of the ultrasonic treatment is 40-50 kHz, and the time of the ultrasonic treatment is 30-50 min.

[0019] Further, in S3, the heating rate of the heating and temperature rising is 4-6 °C / min.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The p-type semiconductor characteristics of vanadium trioxide in the present invention form a heterojunction with cuprous oxide, adjust the conduction band position (shift 0.1-0.2 eV in the negative direction), enhance the built-in electric field strength, promote the rapid separation of photo-generated electron-hole pairs, reduce the recombination probability, and thus improve the optoelectronic conversion efficiency.

[0022] In the acid-leached rice husk ash of the present invention, the surface hydroxyl groups bond with the unsaturated vanadium-oxygen bonds on the surface of vanadium trioxide through hydrogen bonds or coordination bonds to achieve stable bonding and form a stable chemical bonding interface. On the one hand, the carrier transport path is optimized, the interfacial recombination loss is reduced, and thus the photoelectric conversion efficiency is synergistically improved; on the other hand, a composite filling layer is formed, the density of the composite filling is increased, the pores of the cuprous oxide thin film are effectively sealed, and the connectivity of the water molecule penetration path is reduced, thereby synergistically reducing the decline rate of the photoelectric conversion efficiency of the prepared photoelectric conversion material in a high-humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a data comparison trend diagram of the photoelectric conversion efficiency PCE0 and PCE1 of the organic solar cells prepared before and after the photoelectric conversion materials of Examples 1-3 and Comparative Examples 1-3 in the present invention are soaked in normal-temperature water for 24 hours.

[0024] Figure 2 It is a data comparison trend diagram of the decline rate X of the photoelectric conversion efficiency of the organic solar cells prepared before and after the photoelectric conversion materials of Examples 1-3 and Comparative Examples 1-3 in the present invention are soaked in normal-temperature water for 24 hours. DETAILED DESCRIPTION OF THE INVENTION

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0026] Example 1: (1) Preparation of acid-leached rice husk ash, and the preparation method steps are as follows:

[0027] A1. Immerse the rice husk in a sulfuric acid solution with a mass fraction of 1.8%, with a solid-liquid ratio of 1:30. After soaking at normal temperature for 2.2 hours, filter it out, wash it with water until neutral, and air-dry it naturally to obtain acid-treated rice husk.

[0028] A2. Place the acid-treated rice husk obtained in A1 in a crucible, then put it into a muffle furnace, calcine it at 540°C for 1.8 hours, take it out, and perform steam treatment, that is, expose it to 100°C steam for 50 minutes. After promoting the surface hydroxylation reaction through water molecule adsorption, air-dry it naturally to obtain acid-leached rice husk ash.

[0029] (2) Preparation of a metal oxide-doped photoelectric conversion material, and the preparation method steps are as follows:

[0030] S1. After grinding vanadium trioxide and acid-leached rice husk ash respectively, vanadium trioxide nanoparticles and acid-leached rice husk ash nanoparticles are obtained, and the particle sizes of both are less than 100 nm. According to the doping ratio, the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles are put into deionized water at a mass ratio of 2.3:3.7, then a dispersant polyvinylpyrrolidone is added, and then ultrasonic treatment is carried out. Specifically, the frequency of ultrasonic treatment is 45 kHz, and the time of ultrasonic treatment is 40 min to ensure uniform dispersion, obtaining a mixed suspension. Among them, the sum of the masses of the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles accounts for 6% of the mass of the mixed suspension, and the mass of the dispersant polyvinylpyrrolidone accounts for 0.25% of the mass of the mixed suspension. Among them, the dispersant polyvinylpyrrolidone is BASF LUVITEC K90 Powder polyvinylpyrrolidone.

[0031] S2. The mixed suspension obtained in S1 is uniformly coated on the surface of the cuprous oxide film by spin coating (rotation speed 2500 rpm, time 50 s), so that the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles diffuse into the pores of the cuprous oxide film. Here, the Brownian motion and capillary action of the nanoparticles are utilized to make the nanoparticles diffuse into the pores of the cuprous oxide film (pore diameter 50 - 200 nm), and then the water is drained, that is, it is placed in a vacuum drying oven (pressure -0.1 MPa, temperature 55 °C) for treatment for 3.5 h to ensure that there is no residual solvent in the pores, obtaining a composite coated film.

[0032] S3. The composite coated film obtained in S2 is placed in a tube furnace. Under the protection of an inert gas nitrogen, it is heated to 320 °C at a heating rate of 5 °C / min, kept warm for 1.5 h, and then naturally cooled to room temperature, obtaining a metal oxide doped optoelectronic conversion material. The doping amount of vanadium trioxide is 2.3%, and the doping amount of acid-leached rice husk ash is 3.7%.

[0033] Among them, the preparation method of the cuprous oxide film is the prior art.

[0034] The reagents used include: copper sulfate, sodium citrate, sodium sulfate, methanol, ammonium hydroxide, HCl, etc. Methylene blue is the degradation pollutant for experimental testing.

[0035] Specific preparation method: The cuprous oxide film is prepared on a copper sheet by an electrochemical method. Take 20 mL of 0.1 M copper sulfate solution, add 2 g / L of sodium citrate, and dilute it to 200 ml as the electrolyte, and at the same time add 0.05 M of sodium sulfate to adjust the solution pH value. The electrode material is a copper sheet, and the electrode area is 1 cm 2, the anode is a copper sheet, and at the same time, stainless steel is used as the cathode with an electrode spacing of 1 cm. During the electrolysis process, the electrode potential is maintained at 1.5 V, the electrolysis time is 240 min, and the electrolysis temperature is maintained at 22 ± 2 °C. Finally, the electrode sheet is removed, washed with water, washed with alcohol and dried to prepare a cuprous oxide thin film.

[0036] Example 2: Preparation of a metal oxide-doped optoelectronic conversion material, and the preparation method steps are as follows:

[0037] S1. After respectively grinding vanadium trioxide and acid-leached rice husk ash, vanadium trioxide nanoparticles and acid-leached rice husk ash nanoparticles are obtained, and the particle sizes of both are less than 100 nm. According to the doping ratio, the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles are put into deionized water at a mass ratio of 2:3, and then a dispersant polyvinylpyrrolidone is added, and then ultrasonic treatment is carried out. Specifically, the frequency of ultrasonic treatment is 40 kHz, and the time of ultrasonic treatment is 50 min to ensure uniform dispersion and obtain a mixed suspension. Among them, the sum of the masses of the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles accounts for 5% of the mass of the mixed suspension, and the mass of the dispersant polyvinylpyrrolidone accounts for 0.15% of the mass of the mixed suspension.

[0038] S2. The mixed suspension obtained in S1 is uniformly coated on the surface of the cuprous oxide thin film by spin coating (rotation speed 2500 rpm, time 50 s) so that the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles diffuse into the pores of the cuprous oxide thin film. Here, the Brownian motion and capillary action of the nanoparticles are utilized to make the nanoparticles diffuse into the pores of the cuprous oxide thin film (pore diameter 50 - 200 nm), and then the water is drained, that is, it is placed in a vacuum drying oven (pressure -0.1 MPa, temperature 55 °C) for treatment for 3 h to ensure that there is no residual solvent in the pores and obtain a composite coated thin film.

[0039] S3. The composite coated thin film obtained in S2 is placed in a tubular furnace, and under the protection of an inert gas nitrogen, it is heated to 300 °C at a heating rate of 4 °C / min, kept warm for 2 h, and then naturally cooled to room temperature to obtain a metal oxide-doped optoelectronic conversion material. The doping amount of vanadium trioxide is 2%, and the doping amount of acid-leached rice husk ash is 3%.

[0040] Example 3: Preparation of a metal oxide-doped optoelectronic conversion material, and the preparation method steps are as follows:

[0041] S1. After separately grinding vanadium trioxide and acid-leached rice husk ash, vanadium trioxide nanoparticles and acid-leached rice husk ash nanoparticles are obtained, and the particle sizes of both are less than 100 nm. According to the doping ratio, the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles are put into deionized water at a mass ratio of 2.5:4, then a dispersant polyvinylpyrrolidone is added, and then ultrasonic treatment is carried out. Specifically, the frequency of the ultrasonic treatment is 50 kHz, and the time of the ultrasonic treatment is 30 min to ensure uniform dispersion, and a mixed suspension is obtained. Among them, the sum of the masses of the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles accounts for 6.5% of the mass of the mixed suspension, and the mass of the dispersant polyvinylpyrrolidone accounts for 0.35% of the mass of the mixed suspension.

[0042] S2. The mixed suspension obtained in S1 is uniformly coated on the surface of the cuprous oxide film by spin coating (rotation speed 2500 rpm, time 50 s) so that the vanadium trioxide nanoparticles and the acid-leached rice husk ash nanoparticles diffuse into the pores of the cuprous oxide film. Here, the Brownian motion and capillary action of the nanoparticles are utilized to make the nanoparticles diffuse into the pores of the cuprous oxide film (pore diameter 50 - 200 nm), and then the water is dried, that is, it is placed in a vacuum drying oven (pressure -0.1 MPa, temperature 55 °C) for treatment for 4 h to ensure that there is no residual solvent in the pores, and a composite coated film is obtained.

[0043] S3. The composite coated film obtained in S2 is placed in a tubular furnace. Under the protection of an inert gas nitrogen, it is heated to 330 °C at a heating rate of 6 °C / min, kept warm for 1 h, and then naturally cooled to room temperature to obtain a metal oxide doped optoelectronic conversion material. The doping amount of vanadium trioxide is 2.5%, and the doping amount of acid-leached rice husk ash is 4%.

[0044] Comparative Example 1: The difference between this comparative example and Example 1 is that no vanadium trioxide and acid-leached rice husk ash are doped, that is, the optoelectronic conversion material directly uses the cuprous oxide film of the prior art.

[0045] Comparative Example 2: The difference between this comparative example and Example 1 is that vanadium trioxide is deleted; that is, the cuprous oxide film is doped with acid-leached rice husk ash alone.

[0046] Specifically, to prepare a metal oxide doped optoelectronic conversion material, the preparation method steps are as follows:

[0047] S1. After grinding the acid-leached rice husk ash, acid-leached rice husk ash nanoparticles with a particle size less than 100 nm are obtained. The acid-leached rice husk ash nanoparticles are put into deionized water, and then the dispersant polyvinylpyrrolidone is added, and then ultrasonic treatment is carried out. Specifically, the frequency of ultrasonic treatment is 45 kHz, and the time of ultrasonic treatment is 40 min to ensure uniform dispersion, and a mixed suspension is obtained. Among them, the mass of the acid-leached rice husk ash nanoparticles is 3.7% of the mass of the mixed suspension, and the mass of the dispersant polyvinylpyrrolidone accounts for 0.25% of the mass of the mixed suspension.

[0048] S2. The mixed suspension obtained in S1 is uniformly coated on the surface of the cuprous oxide film by spin coating (rotation speed 2500 rpm, time 50 s) so that the acid-leached rice husk ash nanoparticles diffuse into the pores of the cuprous oxide film, and then the water is drained, that is, it is placed in a vacuum drying oven (pressure -0.1 MPa, temperature 55 °C) for treatment for 3.5 h to ensure that there is no residual solvent in the pores, and a composite coated film is obtained.

[0049] S3. The composite coated film obtained in S2 is placed in a tube furnace, and under the protection of the inert gas nitrogen, it is heated to 320 °C at a heating rate of 5 °C / min, kept warm for 1.5 h, and then naturally cooled to room temperature, and the metal oxide-doped optoelectronic conversion material is obtained. The doping amount of the acid-leached rice husk ash is 3.7%.

[0050] Comparative Example 3: The difference between this comparative example and Example 1 is that the acid-leached rice husk ash is deleted; that is, the cuprous oxide film is doped with vanadium trioxide alone.

[0051] Specifically, for the preparation of the metal oxide-doped optoelectronic conversion material, the preparation method steps are as follows:

[0052] S1. After grinding vanadium trioxide, vanadium trioxide nanoparticles with a particle size less than 100 nm are obtained. The vanadium trioxide nanoparticles are put into deionized water, and then the dispersant polyvinylpyrrolidone is added, and then ultrasonic treatment is carried out. Specifically, the frequency of ultrasonic treatment is 45 kHz, and the time of ultrasonic treatment is 40 min to ensure uniform dispersion, and a mixed suspension is obtained. Among them, the mass of the vanadium trioxide nanoparticles accounts for 2.3% of the mass of the mixed suspension, and the mass of the dispersant polyvinylpyrrolidone accounts for 0.25% of the mass of the mixed suspension.

[0053] S2. The mixed suspension obtained in S1 is uniformly coated on the surface of the cuprous oxide film by spin coating (rotation speed 2500 rpm, time 50 s) so that the vanadium trioxide nanoparticles diffuse into the pores of the cuprous oxide film, and then the water is drained, that is, it is placed in a vacuum drying oven (pressure -0.1 MPa, temperature 55 °C) for treatment for 3.5 h to ensure that there is no residual solvent in the pores, and a composite coated film is obtained.

[0054] S3. Place the composite coating film obtained in S2 in a tubular furnace. Under the protection of an inert gas, nitrogen, heat it at a heating rate of 5 °C / min to 320 °C. After holding for 1.5 h, cool it naturally to room temperature to obtain a metal oxide-doped photoelectric conversion material. The doping amount of vanadium trioxide is 2.3%.

[0055] Test examples: Test objects: The photoelectric conversion materials of Examples 1 - 3 and Comparative Examples 1 - 3.

[0056] Test method: ① Measure the photoelectric conversion efficiency PCE0 of each test object;

[0057] ② Measure the photoelectric conversion efficiency PCE1 of each test object after soaking in normal-temperature water for 24 h;

[0058] ③ Calculate the decline rate X of the photoelectric conversion efficiency of each test object before and after water soaking;

[0059] X = (PCE0 - PCE1) / PCE0 × 100%.

[0060] The smaller the value of X, the better the ability to maintain the photoelectric conversion efficiency before and after water soaking.

[0061] Irradiate the film of each test object with a solar simulator (AM 1.5G, 100 mW·cm -2 ), and measure the photocurrent density (J ph ) and open-circuit voltage (V oc ) in combination with an electrochemical workstation.

[0062] Efficiency formula: PCE = (J ph × V oc × FF) / P in × 100%; where FF is the fill factor and P in is the incident light power.

[0063] Test results: See Table 1.

[0064] Table 1

[0065] <![CDATA[PCE0 / %]]> <![CDATA[PCE1 / %]]> X / ％ Example 1 3.22 2.75 14.6 Example 2 3.23 2.73 15.5 Example 3 3.19 2.72 14.7 Comparative Example 1 2.91 2.38 18.2 Comparative Example 2 2.75 2.19 20.4 Comparative Example 3 3.03 2.51 17.2

[0066] Result analysis: Analyze Examples 1 - 3 and combine the data in Table 1 and Figure 1 - Figure 2 , it can be seen that the measured data of the photoelectric conversion efficiency of the photoelectric conversion materials prepared in the present invention (Examples 1 - 3) reach more than 3.19%, and the decline rate of the photoelectric conversion efficiency of the photoelectric conversion materials before and after water soaking is as low as below 15.5%. It shows that the present invention can well maintain the photoelectric conversion efficiency of the photoelectric conversion materials in a high-humidity environment.

[0067] Analyze Example 1 and Comparative Examples 1 - 3 and combine the data in Table 1 andFigure 1 - Figure 2 By comparing Comparative Example 1 and Comparative Example 2, it can be seen that doping cuprous oxide thin film with acid-leached rice husk ash alone will lead to a decrease in the photoelectric conversion efficiency and an increase in the decline rate of the photoelectric conversion efficiency before and after water immersion. This is because the surface of the acid-leached rice husk ash has a high degree of hydroxylation, and it is easy to form interfacial stress when combined with the cuprous oxide lattice, resulting in an increase in microcracks and porosity inside the thin film, providing more channels for water molecule penetration.

[0068] By comparing Comparative Example 1 and Comparative Example 3, it can be seen that doping cuprous oxide thin film with vanadium trioxide alone can improve the photoelectric conversion efficiency, and the decline rate of the photoelectric conversion efficiency before and after water immersion is reduced. This is because the p-type semiconductor characteristics of vanadium trioxide form a heterojunction with cuprous oxide, adjusting the conduction band position (shifting 0.1 - 0.2 eV in the negative direction), enhancing the built-in electric field strength, promoting the rapid separation of photo-generated electron-hole pairs, reducing the recombination probability, and thus improving the photoelectric conversion efficiency.

[0069] Combined with the comparison of Example 1, it can be seen that doping cuprous oxide thin film with both acid-leached rice husk ash and vanadium trioxide can synergistically improve the photoelectric conversion efficiency and synergistically reduce the decline rate of the photoelectric conversion efficiency in a high-humidity environment. This is because the surface hydroxyl groups of the acid-leached rice husk ash are stably bonded to the unsaturated vanadium-oxygen bonds on the surface of vanadium trioxide through hydrogen bonds or coordination bonds to form a stable chemical bonding interface. On the one hand, it optimizes the carrier transport path, reduces the interfacial recombination loss, and thus synergistically improves the photoelectric conversion efficiency; on the other hand, it forms a composite filling layer, improves the density of the composite filling, effectively seals the pores of the cuprous oxide thin film, and reduces the connectivity of the water molecule penetration path, thereby synergistically reducing the decline rate of the photoelectric conversion efficiency of the prepared photoelectric conversion material in a high-humidity environment.

[0070] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A metal oxide-doped photoelectric conversion material, characterized in that, It includes cuprous oxide thin film, acid-leached rice husk ash doped with the cuprous oxide thin film and vanadium pentoxide.

2. The metal oxide-doped optoelectronic conversion material according to claim 1, wherein The doping mass fraction of the acid-leached rice husk ash is 3%-4%.

3. The metal oxide-doped optoelectronic conversion material according to claim 1, wherein The doping mass fraction of the vanadium pentoxide is 2%-2.5%.

4. The metal oxide-doped optoelectronic conversion material according to claim 1, wherein The preparation method of the acid-leached rice husk ash is as follows: A1. Immerse the rice husk in a sulfuric acid solution with a mass fraction of 1.5-2%, soak for 2-2.5 h at room temperature, then filter out, wash with water until neutral, and air dry naturally to obtain acid-treated rice husk. A2. Place the acid-treated rice husk obtained in A1 in a muffle furnace, calcine at 520-550 °C for 1.5-2 h, take out, perform steam treatment for 45-60 min, and then air dry naturally to obtain acid-leached rice husk ash.

5. A method for preparing a metal oxide-doped optoelectronic conversion material according to any one of claims 1-4, characterized in that, It includes the following steps: S1. Grind vanadium pentoxide and acid-leached rice husk ash respectively to obtain vanadium pentoxide nanoparticles and acid-leached rice husk ash nanoparticles, put them into deionized water according to the doping ratio, add a dispersant, and perform ultrasonic treatment to obtain a mixed suspension. S2. Uniformly coat the mixed suspension obtained in S1 on the surface of the cuprous oxide thin film, with a coating thickness of 15-20 μm, and then drain the water to obtain a composite coating film. S3. Under the protection of inert gas, heat the composite coating film obtained in S2 to 300-330 °C, keep it warm for 1-2 h, and then cool it naturally to room temperature to obtain the metal oxide-doped optoelectronic conversion material.

6. The preparation method of the metal oxide-doped optoelectronic conversion material according to claim 5, characterized in that, In S1, the particle sizes of the vanadium pentoxide nanoparticles and the acid-leached rice husk ash nanoparticles are both less than 100 nm.

7. The preparation method of the metal oxide-doped optoelectronic conversion material according to claim 5, wherein In S1, the dispersant includes polyethylene glycol or polyvinylpyrrolidone.

8. The preparation method of the metal oxide-doped optoelectronic conversion material according to claim 5, wherein, The sum of the masses of the vanadium pentoxide nanoparticles and the acid-leached rice husk ash nanoparticles accounts for 5%-6.5% of the mass of the mixed suspension; the mass of the dispersant accounts for 0.15%-0.35% of the mass of the mixed suspension.

9. The preparation method of the metal oxide-doped optoelectronic conversion material according to claim 5, wherein, In S1, the frequency of the ultrasonic treatment is 40-50 kHz, and the time of the ultrasonic treatment is 30-50 min.

10. The preparation method of the metal oxide-doped optoelectronic conversion material according to claim 5, characterized in that, In S3, the heating rate of the heating-up is 4-6 °C / min.

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