Method for preparing environment-stable all-inorganic perovskite solar cells by quantum dot modification

Abstract

The application belongs to the technical field of perovskite solar cells, and discloses a method for preparing a full-inorganic perovskite solar cell by quantum dot modification, wherein a metal particle film is used as a cathode, a W-doped Nb2O5 particle film is used as an electron transport layer, a quantum dot modified CsPbI2Br film is used as a light absorbing layer of the solar cell, a Cu-doped NiO particle film is used as a hole transport layer, a high light transmittance support material integrated with a conductive coating is used as an anode and a substrate, and a laminated solar cell is prepared. The application is helpful for pre-crystallization of a full-inorganic perovskite light absorbing layer and quantum dot coordination modification. After the substrate is transferred to a heating table for annealing, a quantum dot modified full-inorganic perovskite absorbing layer is prepared. Through subsequent annealing, the size of CsPbI2Br particles is increased, the light absorption of the light absorbing layer and the separation of electron-hole pairs are improved, the size of the CsPbI2Br particles is increased, the defect state density is reduced, and the separation and migration of photo-generated electron-hole pairs are improved.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, and particularly relates to a method for preparing all-inorganic perovskite solar cells by quantum dot modification. Background Technology

[0002] Currently, organic-inorganic hybrid perovskite solar cells (OIHPSCs) possess extremely high photoelectric conversion efficiency and have attracted widespread attention in the new energy field. However, the core component of OIHPSCs—organic cation ligands—is highly volatile, resulting in poor environmental stability and significantly hindering their practical application. All-inorganic perovskite solar cells (CsPbI₂Br-PSCs) contain no volatile organic compounds and possess excellent optical properties and structural stability, making them ideal materials for fabricating the light-absorbing layer of solar cells. However, these materials are easily corroded by moisture and have a relatively high defect state density, meaning their photoelectric conversion efficiency and environmental stability still fall short of the requirements of the commercial photovoltaic industry. Therefore, improving the efficiency and water resistance of all-inorganic perovskite solar cells is crucial.

[0003] Based on the above analysis, the problems and defects of the existing technology are as follows: the existing devices have low efficiency and are not resistant to water corrosion in actual use. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for preparing all-inorganic perovskite solar cells by quantum dot modification.

[0005] This invention is implemented as follows: A method for preparing an all-inorganic perovskite solar cell using quantum dot modification specifically includes: using a metal particle film as the cathode, a W-doped Nb2O5 particle film as the electron transport layer, a quantum dot-modified CsPbI2Br film as the light-absorbing layer of the solar cell, a Cu-doped NiO particle film as the hole transport layer, and a high-transmittance support material with an integrated conductive coating as the positive electrode and substrate, thereby preparing a tandem solar cell.

[0006] Step 1: Preparation of CsPbB3 quantum dot dispersion system;

[0007] Step 2: Preparation of the all-inorganic perovskite light-absorbing layer—CsPbI2 precursor;

[0008] Step 3: Substrate cutting and cleaning;

[0009] Step 4: Deposit a Cu-doped NiO hole transport layer on the substrate;

[0010] Step 5: On the substrate surface prepared in Step 4 above with a hole transport layer deposited, a CsPbI2Br precursor and a CsPbB3 quantum dot dispersion are spin-coated sequentially. During the spin-coating process, the substrate is kept at 40-160℃, which helps the pre-crystallization of the all-inorganic perovskite light-absorbing layer and the quantum dot coordination modification. After spin-coating, the substrate is transferred to a heating stage for annealing to prepare the quantum dot-modified all-inorganic perovskite absorption layer.

[0011] Step 6: Deposit a W-doped Nb2O5 electron transport layer on the substrate surface where the absorption layer was prepared in step 5. The thickness of both the electron transport layer and the hole transport layer is between 20-100 nm.

[0012] Step 7: Deposit a metal film on the substrate surface where the electron transport layer was prepared in Step 6 as a cathode;

[0013] Step 8: The cathode, which has been prepared in Step 7, is cut into devices of suitable size and shape and then annealed in one step to increase the connection between the functional layers and ensure the free transport of electrons between them. The annealed sample is the all-inorganic perovskite solar cell.

[0014] Furthermore, the preparation of the quantum dot dispersion system and the all-inorganic perovskite light-absorbing layer precursor solution in steps one and two is carried out in an oxygen-free environment, and the preparation interval should be short, and they should be prepared as simultaneously as possible to avoid the impact of different storage times on the uniformity of their dispersion systems.

[0015] Furthermore, the doping amounts of Cu and W in steps four and six can be controlled by adjusting the deposition rate to improve the migration efficiency of electrons and holes. The deposition method can be laser pulse deposition, dual-source electron beam deposition, atomic layer deposition, or thermal evaporation, among others.

[0016] Furthermore, the CsPbB3 dispersion system and CsPbI2Br precursor selected for the light-absorbing layer are preferably freshly prepared. The spin coater speed is maintained at 1500-5000 rpm to ensure the uniformity of the modified light-absorbing layer. The annealing temperature is below 200℃, and the annealing time is between 30 minutes and 2 hours. Finally, the molar ratio of quantum dots to light-absorbing layer is controlled at 0.02-0.006:1, and the thickness of the light-absorbing layer is 500-2000 nanometers.

[0017] Furthermore, in step seven, the metal film electrode is prepared by atomic layer deposition and its thickness is controlled between 20-300 nm. The composition is one or more of gold, silver, copper, titanium, etc.

[0018] Furthermore, in step eight, the device is annealed in an inert atmosphere at a temperature of 250-500°C for about 1 hour. During the annealing process, volatile organic compounds in the light-absorbing layer are further removed.

[0019] Another objective of this invention is to provide a quantum dot-modified, environmentally stable all-inorganic perovskite solar cell, comprising: a stacked substrate layer, a hole transport layer, a light-absorbing layer, an electron transport layer, and a cathode; characterized in that an inorganic quantum dot layer with a size of less than 10 nanometers is modified and grown on the upper surface of the all-inorganic perovskite light-absorbing layer, the quantum dot layer being composed of monodisperse CsPbB3 quantum dots.

[0020] The light-absorbing layer is an all-inorganic perovskite CsPbI2Br, and the surface modification layer is a pre-prepared quantum dot material. The quantum dot material and the light-absorbing layer material are not simply coated and wrapped. After the light-absorbing layer reacts and grows, the quantum dot layer increases the particle size of the light-absorbing layer while reducing the defect density of the light-absorbing layer.

[0021] The substrate layer includes ITO quartz glass, FTO quartz glass, sapphire, and a PC film coated with conductive polymer. The substrate layer also integrates the solar cell anode and should have high light flux and conductivity.

[0022] The hole transport layer is a Cu-doped NiO film deposited on the surface of a conductive substrate by vapor deposition, with adjustable composition and ratio; the electron transport layer is a W-doped Nb2O5 film deposited on the surface of the light-absorbing layer, with adjustable composition and ratio; the cathode is a stable conductive film, whose composition is one or a combination of gold, silver, titanium, molybdenum, aluminum, platinum, copper, etc.

[0023] The thickness of the hole transport layer and the electron transport layer, as well as their particle size, are adjustable, which can be achieved through the deposition rate, deposition time, and deposition method. Deposition methods can include electron beam deposition, laser pulse deposition, magnetron sputtering deposition, thermal evaporation deposition, etc.

[0024] The CsPbI2Br precursor was integrated into the hole transport layer by spin coating and heating. The thickness of the light-absorbing layer was controlled by adjusting the concentration of the suspension, and the crystallinity of the light-absorbing layer particles was controlled by adjusting the heating temperature.

[0025] The CsPbI2Br precursor is generally a suspension, and the solvent is a volatile organic solvent such as DMF, DMSO, or tetrahydrofuran, which is easy to volatilize during subsequent heating to form a dense all-inorganic absorber layer.

[0026] Similarly, CsPbB3 quantum dots were uniformly coated onto the surface of CsPbI2Br particles by spin coating, and then a light-absorbing layer with large particle size and low defect density was further induced by subsequent heat treatment.

[0027] The CsPbB3 quantum dots used in spin coating are also in the form of a dispersion, and the solvent is a highly volatile organic solvent such as n-hexane or n-hexene that leaves little residue.

[0028] The thickness of the CsPbB3 quantum dot layer is adjustable, which is achieved by controlling the concentration of the quantum dot solution.

[0029] The construction process of all functional components of the perovskite solar cell involves very little organic matter, and the final device achieves a complete absence of organic components. This solar cell is a fully inorganic perovskite solar cell.

[0030] The quantum dot-modified, environmentally stable all-inorganic perovskite solar cell has a stacked structure with the following thicknesses for each functional layer: substrate layer for integrated anode, substrate layer for support, thickness 0.1-0.5 mm, anode layer thickness 250-400 nm; hole transport layer, 20-100 nm; quantum dot-modified all-inorganic perovskite light-absorbing layer, total thickness 500-2000 nm; electron transport layer, 20-100 nm; cathode, 20-300 nm.

[0031] Another object of the present invention is to provide an all-inorganic perovskite solar cell prepared by the method of preparing all-inorganic perovskite solar cells by the modification of the quantum dots.

[0032] Another object of the present invention is to provide a drone equipped with the aforementioned all-inorganic perovskite solar cell.

[0033] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0034] First, addressing the technical problems existing in the prior art and the difficulty in solving them, this paper closely analyzes, in conjunction with the technical solution to be protected by this invention and the results and data obtained during the research and development process, how the technical solution of this invention solves the technical problems, and the inventive technical effects brought about by solving these problems. The specific description is as follows:

[0035] This invention discloses a method for preparing an all-inorganic perovskite solar cell using quantum dot modification. By growing a layer of CsPbB3 quantum dots on the surface of a CsPbI2Br particle film, the intrusion of water molecules can be effectively blocked, improving the water resistance of CsPbI2Br. Simultaneously, the quantum dots are pre-attached to the CsPbI2Br surface in the form of a dispersion, ensuring their uniform distribution. Subsequent annealing induces an increase in the size of the CsPbI2Br particles, reducing defect density and ultimately improving the light absorption and electron-hole pair separation of the light-absorbing layer. Furthermore, during the heat treatment process, the potentially volatile solution inside the light-absorbing layer is fully volatilized, ensuring the all-inorganic properties of the light-absorbing layer and further improving its thermal stability. The integration of quantum dots and CsPbI2Br into a complete light-absorbing layer reduces steric hindrance and interfacial obstruction in the electron-hole pair separation process, further enhancing photoelectric efficiency.

[0036] Second, considering the technical solution as a whole or from a product perspective, the technical effects and advantages of the technical solution to be protected by this invention are specifically described as follows:

[0037] This invention discloses a method for preparing all-inorganic perovskite solar cells using quantum dot modification. The quantum dots are grown on the surface of CsPbI₂Br, forming a dense water-blocking layer on the light-absorbing layer surface. This layer effectively isolates the cell from moisture in the environment, significantly improving its operational stability. Furthermore, quantum dot modification of CsPbI₂Br increases the particle size and reduces the defect state density, thereby enhancing the separation and migration of photogenerated electrons and holes and improving photoelectric conversion efficiency. Attached Figure Description

[0038] Figure 1 This is a scanning electron microscope image of the quantum dot-modified all-inorganic perovskite light-absorbing layer provided in the embodiments of the present invention;

[0039] Figure 2 This is a test curve of the all-inorganic perovskite solar cell provided in an embodiment of the present invention;

[0040] Figure 3 These are optical photographs of the all-inorganic perovskite solar cell provided in this embodiment of the invention exposed to air for 8 hours.

[0041] Figure 4 This refers to the retention rate of the photoelectric conversion efficiency of the all-inorganic perovskite solar cell provided in this embodiment of the invention after being exposed to air for 60 hours.

[0042] Figure 5 This is a structural diagram of an all-inorganic perovskite provided in an embodiment of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] To enable those skilled in the art to fully understand how the present invention is specifically implemented, this section provides an explanatory description of the embodiments that expand upon the technical solutions of the claims.

[0045] like Figure 1 - Figure 4 As shown, the method for preparing an all-inorganic perovskite solar cell using quantum dot modification provided in this embodiment of the invention includes:

[0046] Step 1: Preparation of CsPbB3 quantum dot dispersion system;

[0047] Step 2: Preparation of the all-inorganic perovskite light-absorbing layer—CsPbI2 precursor;

[0048] Step 3: Substrate cutting and cleaning;

[0049] Step 4: Deposit a Cu-doped NiO hole transport layer on the substrate;

[0050] Step 5: On the substrate surface prepared in Step 4 above with a hole transport layer deposited, a CsPbI2Br precursor and a CsPbB3 quantum dot dispersion are spin-coated sequentially. During the spin-coating process, the substrate is kept at 40-160℃, which helps the pre-crystallization of the all-inorganic perovskite light-absorbing layer and the quantum dot coordination modification. After spin-coating, the substrate is transferred to a heating stage for annealing to prepare the quantum dot-modified all-inorganic perovskite absorption layer.

[0051] Step 6: Deposit a W-doped Nb2O5 electron transport layer on the substrate surface where the absorption layer was prepared in step 5. The thickness of both the electron transport layer and the hole transport layer is between 20-100 nm.

[0052] Step 7: Deposit a metal film on the substrate surface where the electron transport layer was prepared in Step 6 as a cathode;

[0053] Step 8: The cathode, which has been prepared in Step 7, is cut into devices of suitable size and shape and then annealed in one step to increase the connection between the functional layers and ensure the free transport of electrons between them. The annealed sample is the all-inorganic perovskite solar cell.

[0054] Furthermore, the preparation of the quantum dot dispersion system and the all-inorganic perovskite light-absorbing layer precursor solution in steps one and two is carried out in an oxygen-free environment, and the preparation interval should be short, and they should be prepared as simultaneously as possible to avoid the impact of different storage times on the uniformity of their dispersion systems.

[0055] Furthermore, the doping amounts of Cu and W in steps four and six can be controlled by adjusting the deposition rate to improve the migration efficiency of electrons and holes. The deposition method can be laser pulse deposition, dual-source electron beam deposition, atomic layer deposition, or thermal evaporation, among others.

[0056] Furthermore, the CsPbB3 dispersion system and CsPbI2Br precursor selected for the light-absorbing layer are preferably freshly prepared. The spin coater speed is maintained at 1500-5000 rpm to ensure the uniformity of the modified light-absorbing layer. The annealing temperature is below 200℃, and the annealing time is between 30 minutes and 2 hours. Finally, the molar ratio of quantum dots to light-absorbing layer is controlled at 0.02-0.006:1, and the thickness of the light-absorbing layer is 500-2000 nanometers.

[0057] Furthermore, in step seven, the metal film electrode is prepared by atomic layer deposition and its thickness is controlled between 20-300 nm. The composition is one or more of gold, silver, copper, titanium, etc.

[0058] Furthermore, in step eight, the device is annealed in an inert atmosphere at a temperature of 250-500°C for about 1 hour. During the annealing process, volatile organic compounds in the light-absorbing layer are further removed.

[0059] Another objective of this invention is to provide a quantum dot-modified, environmentally stable all-inorganic perovskite solar cell comprising: a stacked substrate layer, a hole transport layer, a light-absorbing layer, an electron transport layer, and a cathode; wherein an inorganic quantum dot layer with a size of less than 10 nanometers is modified and grown on the upper surface of the all-inorganic perovskite light-absorbing layer, the quantum dot layer being composed of monodisperse CsPbB3 quantum dots.

[0060] The light-absorbing layer is an all-inorganic perovskite CsPbI2Br, and the surface modification layer is a pre-prepared quantum dot material. The quantum dot material and the light-absorbing layer material are not simply coated and wrapped. After the light-absorbing layer reacts and grows, the quantum dot layer increases the particle size of the light-absorbing layer while reducing the defect density of the light-absorbing layer.

[0061] The substrate includes, but is not limited to, ITO quartz glass, FTO quartz glass, sapphire, and PC film coated with conductive polymer. The substrate also integrates the solar cell anode and should have high light flux and conductivity.

[0062] The hole transport layer is a Cu-doped NiO film deposited on the surface of a conductive substrate by vapor deposition, with adjustable composition and ratio; the electron transport layer is a W-doped Nb2O5 film deposited on the surface of a light-absorbing coating, with adjustable composition and ratio; the cathode is a stable conductive film, whose composition is one or a combination of gold, silver, titanium, molybdenum, aluminum, platinum, copper, etc.

[0063] The thickness of the hole transport layer and the electron transport layer, as well as their particle size, are adjustable, which can be achieved through deposition rate, deposition time, and deposition method. Deposition methods can include electron beam deposition, laser pulse deposition, magnetron sputtering deposition, thermal evaporation deposition, etc.

[0064] The CsPbI2Br precursor was integrated into the hole transport layer by spin coating and heating. The thickness of the light-absorbing layer was controlled by adjusting the concentration of the suspension, and the crystallinity of the light-absorbing layer particles was controlled by adjusting the heating temperature.

[0065] The CsPbI2Br precursor is generally a suspension, and the solvent is a volatile organic solvent such as DMF, DMSO, or tetrahydrofuran, which is easy to volatilize during subsequent heating to form a dense all-inorganic absorber layer.

[0066] Similarly, CsPbB3 quantum dots were uniformly coated onto the surface of CsPbI2Br particles by spin coating, and then a light-absorbing layer with large particle size and low defect density was further induced by subsequent heat treatment.

[0067] The CsPbB3 quantum dots used in spin coating are also in the form of a dispersion, and the solvent is a highly volatile organic solvent such as n-hexane or n-hexene that leaves little residue.

[0068] The thickness of the CsPbB3 quantum dot layer is adjustable, which is achieved by controlling the concentration of the quantum dot solution.

[0069] The construction process of all functional components of the perovskite solar cell involves very little organic matter, and the final device achieves a complete absence of organic components. This solar cell is a fully inorganic perovskite solar cell.

[0070] The quantum dot-modified, environmentally stable all-inorganic perovskite solar cell has a stacked structure with the following thicknesses for each functional layer: substrate layer for integrated anode, supporting substrate layer thickness 0.1-0.5 mm, anode layer thickness 250-400 nm; hole transport layer, 20-100 nm; quantum dot-modified all-inorganic perovskite light-absorbing layer, total thickness 500-2000 nm; electron transport layer 20-100 nm; cathode 20-300 nm.

[0071] Example 1:

[0072] (1): Take a piece of ITO quartz glass with a size of 1*1cm and clean it with surfactant-type detergent, ethanol, deionized water, acetone, etc. After cleaning, place it in acetone for later use.

[0073] (2): Accurately weigh 276 mg lead iodide (PbI2), 220 mg lead bromide (PbBr2) and 310 mg cesium iodide (CsI) and place them in 1 mL of dimethyl sulfoxide (DMSO) and stir magnetically for 24 hours to obtain the CsPbI2Br precursor.

[0074] (3): Weigh 85 mg of cesium bromide (CsBr) and 146 mg of lead iodide (PbI2) and add them to a mixture of 1 mL of oleic acid (OA), 0.5 mL of oleylamine (OAM) and 10 mL of dimethylformamide (DMF), and stir magnetically to form a homogeneous dispersion. Take 1 mL of the above dispersion and add it dropwise to 10 mL of toluene (TOL) while stirring, and continue stirring for 10 minutes. Then add 20 mL of ethyl acetate / methyl acetate solvent with a volume ratio of 1:1 to the dispersion, let it stand, and centrifuge. The precipitate at the bottom is the concentrated CsPbB3 quantum dot dispersion system. Finally, add the concentrated quantum dots to 5 mL of n-hexane to prepare a 10 mg / mL quantum dot solution.

[0075] (4): A hole transport layer was deposited on the substrate using a dual-light source electron beam deposition system. The ITO quartz glass, cleaned in step one, was fixed on the sample stage, and NiO and CuO particles were placed in their respective crucibles. After evacuation, the program was set to control their deposition rates. The resulting Cu-doped NiO (Cu / NiO) thin film with a thickness of 30 nm is the hole transport layer.

[0076] (5): Fix the ITO quartz glass with hole transport layer deposited in step four on a spin coater, take 80 μL of CsPbI2Br precursor prepared in step two and drop it onto the Cu / NiO surface. The spin coating speed is controlled at 3000 rpm. After spin coating time of 30s, transfer it to a heating stage at 50℃ and pre-crystallize for 10 minutes to obtain the intermediate of CsPbI2Br light-absorbing layer.

[0077] (6): Transfer the sample processed in step four back to the spin coater. Take 60 μL of the CsPbB3 quantum dot dispersion prepared in step three and drop it onto the surface of the light-absorbing intermediate of the sample prepared in step four. The spin coating speed is controlled at 2000 rpm. After spin coating for 40 s, transfer it to a heating stage at 100℃ and heat for 30 minutes to promote the crystallization of the light-absorbing layer and the evaporation of the solvent. Finally, a CsPbB3 quantum dot-modified all-inorganic perovskite CsPbI2Br light-absorbing layer is obtained.

[0078] (7): An electron transport layer was prepared using a dual-source electron beam deposition system. The sample prepared in step six was fixed on the sample stage, and WO3 and Nb2O5 particles were placed in their respective crucibles. After evacuation, the program was set to control their deposition rates. The W-doped Nb2O5 (W / Nb2O5) thin film with a light-absorbing layer thickness of 30 nm deposited in the sample is the electron transport layer.

[0079] (8): The cathode was prepared using a dual-source electron beam deposition apparatus. The sample prepared in step seven was fixed on the sample stage, and Ag particles were placed in the corresponding crucibles. After evacuation, the program was set to control the deposition rate. The 10nm thick Ag layer deposited on the sample serves as the cathode.

[0080] (9): The ITO quartz glass with multiple functional layers prepared in steps one to eight was placed in a tube furnace under an argon atmosphere and annealed at 300°C for 1 hour to convert each functional layer into a crystalline material and further remove the organic matter adsorbed on the sample surface. The final device obtained is a quantum dot-modified all-inorganic perovskite solar cell.

[0081] Example 2:

[0082] (1): Take a piece of 10*10cm ITO quartz glass and clean it with surfactant-type detergent, ethanol, deionized water, acetone, etc. After cleaning, place it in acetone for later use.

[0083] (2): Accurately weigh 276 mg lead iodide (PbI2), 220 mg lead bromide (PbBr2) and 310 mg cesium iodide (CsI) and place them in 1 mL of dimethyl sulfoxide (DMSO) and stir magnetically for 24 hours to obtain the CsPbI2Br precursor.

[0084] (3): Weigh 85 mg of cesium bromide (CsBr) and 146 mg of lead iodide (PbI2) and add them to a mixture of 1 mL of oleic acid (OA), 0.5 mL of oleylamine (OAM) and 10 mL of dimethylformamide (DMF), and stir magnetically to form a homogeneous dispersion. Take 1 mL of the above dispersion and add it dropwise to 10 mL of toluene (TOL) while stirring, and continue stirring for 10 minutes. Then add 20 mL of ethyl acetate / methyl acetate solvent with a volume ratio of 1:1 to the dispersion, let it stand, and centrifuge. The precipitate at the bottom is the concentrated CsPbB3 quantum dot dispersion system. Finally, add the concentrated quantum dots to 5 mL of n-hexane to prepare a 10 mg / mL quantum dot solution.

[0085] (4): A hole transport layer was deposited on the substrate using a dual-light source electron beam deposition system. The ITO quartz glass, cleaned in step one, was fixed on the sample stage, and NiO and CuO particles were placed in their respective crucibles. After evacuation, the program was set to control their deposition rates. The resulting Cu-doped NiO (Cu / NiO) thin film with a thickness of 30 nm is the hole transport layer.

[0086] (5): Fix the ITO quartz glass with hole transport layer deposited in step four on a spin coater, take 0.1 mL of the CsPbI2Br precursor prepared in step two and drop it onto the Cu / NiO surface. Control the spin coating speed at 3000 rpm and spin coat for 30 s. After spin coating, transfer it to a heating stage at 50 ℃ and pre-crystallize for 15 minutes to obtain the intermediate of CsPbI2Br light-absorbing layer.

[0087] (6): Transfer the sample processed in step four back to the spin coater. Take 0.07 mL of the CsPbB3 quantum dot dispersion prepared in step three and drop it onto the surface of the light-absorbing intermediate of the sample prepared in step four. The spin coating speed is controlled at 2000 rpm. After spin coating for 40 s, transfer it to a heating stage at 100℃ and heat for 40 minutes to promote the crystallization of the light-absorbing layer and the evaporation of the solvent. Finally, a CsPbB3 quantum dot-modified all-inorganic perovskite CsPbI2Br light-absorbing layer is obtained.

[0088] (7): An electron transport layer was prepared using a dual-source electron beam deposition system. The sample prepared in step six was fixed on the sample stage, and WO3 and Nb2O5 particles were placed in their respective crucibles. After evacuation, the program was set to control their deposition rates. The W-doped Nb2O5 (W / Nb2O5) thin film with a light-absorbing layer thickness of 30 nm deposited in the sample is the electron transport layer.

[0089] (8): The cathode was prepared using a dual-source electron beam deposition apparatus. The sample prepared in step seven was fixed on the sample stage, and Ag particles were placed in the corresponding crucibles. After evacuation, the program was set to control the deposition rate. The 10nm thick Ag layer deposited on the sample serves as the cathode.

[0090] (9): The ITO quartz glass with multiple functional layers prepared in steps one to eight is placed in a tube furnace under an argon atmosphere and annealed at 300°C for 1.2 hours to convert each functional layer into a crystalline material. The final device is a quantum dot-modified all-inorganic perovskite solar cell.

[0091] Example 3:

[0092] (1): Take a piece of 10*10cm ITO quartz glass and clean it with surfactant-type detergent, ethanol, deionized water, acetone, etc. After cleaning, place it in acetone for later use.

[0093] (2): Accurately weigh 557 mg lead iodide (PbI2), 450 mg lead bromide (PbBr2) and 630 mg cesium iodide (CsI) and place them in 2 mL of dimethyl sulfoxide (DMSO) and stir magnetically for 24 hours to obtain the CsPbI2Br precursor.

[0094] (3): Weigh 170 mg of cesium bromide (CsBr) and 146 mg of lead iodide (PbI2) and add them to a mixture of 2 mL of oleic acid (OA), 1 mL of oleylamine (OAM) and 20 mL of dimethylformamide (DMF), and stir magnetically to form a uniform dispersion. Take 1 mL of the above dispersion and add it dropwise to 20 mL of toluene (TOL) while stirring, and continue stirring for 10 minutes. Then add 20 mL of ethyl acetate / methyl acetate solvent with a volume ratio of 1:1 to the dispersion, let it stand, and centrifuge. The precipitate at the bottom is the concentrated CsPbB3 quantum dot dispersion system. Finally, add the concentrated quantum dots to 5 mL of n-hexane to prepare a 10 mg / mL quantum dot solution.

[0095] (4): A hole transport layer was deposited on the substrate using a dual-light source electron beam deposition system. The ITO quartz glass, cleaned in step one, was fixed on the sample stage, and NiO and CuO particles were placed in their respective crucibles. After evacuation, the program was set to control their deposition rates. The resulting Cu-doped NiO (Cu / NiO) thin film with a thickness of 30 nm is the hole transport layer.

[0096] (5): Fix the ITO quartz glass with hole transport layer deposited in step four on a spin coater, take 1 mL of CsPbI2Br precursor prepared in step two and drop it onto the Cu / NiO surface. Control the spin coating speed at 3000 rpm. After spin coating for 30 s, transfer it to a heating stage at 50 ℃ and pre-crystallize for 15 minutes to obtain the intermediate of CsPbI2Br light-absorbing layer.

[0097] (6): Transfer the sample processed in step four back to the spin coater. Take 0.08 mL of the CsPbB3 quantum dot dispersion prepared in step three and drop it onto the surface of the light-absorbing intermediate of the sample prepared in step four. Control the speed at 2000 rpm. After spin coating for 40 s, transfer it to a heating stage at 100℃ and heat for 50 minutes to promote the crystallization of the light-absorbing layer and the evaporation of the solvent. Finally, a CsPbB3 quantum dot-modified all-inorganic perovskite CsPbI2Br light-absorbing layer is obtained.

[0098] (7): An electron transport layer was prepared using a dual-source electron beam deposition system. The sample prepared in step six was fixed on the sample stage, and WO3 and Nb2O5 particles were placed in their respective crucibles. After evacuation, the program was set to control their deposition rates. The W-doped Nb2O5 (W / Nb2O5) thin film with a light-absorbing layer thickness of 30 nm deposited in the sample is the electron transport layer.

[0099] (8): The cathode was prepared using a dual-source electron beam deposition apparatus. The sample prepared in step seven was fixed on the sample stage, and Ag particles were placed in the corresponding crucibles. After evacuation, the program was set to control the deposition rate. The 10nm thick Ag layer deposited on the sample serves as the cathode.

[0100] (9): The ITO quartz glass with multiple functional layers prepared in steps one to eight is placed in a tube furnace under an argon atmosphere and annealed at 280°C for 2 hours. The final device is a quantum dot-modified all-inorganic perovskite solar cell.

[0101] To demonstrate the inventiveness and technical value of the technical solution of this invention, this section provides specific product or related technology application examples of the technical solution claimed.

[0102] The present invention relates to a method for preparing all-inorganic perovskite solar cells by quantum dot modification, which is applied in the manufacture of organic-inorganic hybrid perovskite solar cells.

[0103] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing an all-inorganic perovskite solar cell by quantum dot modification, characterized in that, Using a high-transmittance support material with an integrated conductive coating as the positive electrode and substrate, a Cu-doped NiO particle film is deposited on the substrate as a hole transport layer. A CsPbI2Br precursor and a CsPbBr3 quantum dot dispersion are spin-coated sequentially on the surface of the substrate with the hole transport layer deposited, while the substrate is kept at 40-160℃ throughout the spin-coating process. After spin-coating, the substrate is transferred to a heating stage for annealing to prepare a quantum dot-modified CsPbI2Br film as the light-absorbing layer of the solar cell. A W-doped Nb2O5 particle film is deposited on the surface of the substrate with the absorption layer as an electron transport layer. A metal particle film is deposited on the surface of the substrate with the electron transport layer as a cathode to prepare a tandem solar cell.

2. The method for preparing an all-inorganic perovskite solar cell by quantum dot modification as described in claim 1, characterized in that, The method for constructing an all-inorganic perovskite solar cell is as follows: Step 1: Preparation of CsPbBr3 quantum dot dispersion system; Step 2: Preparation of the all-inorganic perovskite light-absorbing layer—CsPbI2Br precursor; Step 3: Substrate cutting and cleaning; Step 4: Deposit a Cu-doped NiO hole transport layer on the substrate; Step 5: Spin-coat a CsPbI2Br precursor and a CsPbBr3 quantum dot dispersion onto the surface of the prepared substrate with the hole transport layer deposited. Step 6: Deposit a W-doped Nb2O5 electron transport layer on the substrate surface where the absorption layer has been prepared, wherein the thickness of the electron transport layer and the hole transport layer is 20-100 nm; Step 7: Deposit a metal film on the substrate surface where the electron transport layer has been prepared as a cathode; Step 8: The cathode, which has been prepared in Step 7, is cut into devices of suitable size and shape and then annealed in one step to increase the connection between the functional layers and ensure the free transport of electrons between them. The annealed sample is the all-inorganic perovskite solar cell.

3. The method for preparing an all-inorganic perovskite solar cell by quantum dot modification as described in claim 2, characterized in that, The preparation of the quantum dot dispersion system and the all-inorganic perovskite light-absorbing layer precursor solution in steps one and two is carried out in an oxygen-free environment.

4. The method for preparing an all-inorganic perovskite solar cell by quantum dot modification as described in claim 2, characterized in that, In steps four and six, the doping of Cu and W is largely controlled by adjusting the deposition rate; the deposition methods are laser pulse, dual-source electron beam deposition, atomic layer deposition, or thermal evaporation.

5. The method for preparing an all-inorganic perovskite solar cell by quantum dot modification as described in claim 2, characterized in that, The CsPbB coating selected for the light-absorbing layer r3 The dispersion system and CsPbI2Br precursor were freshly formulated, and the spin coater speed was maintained at 1500-5000 rpm, followed by annealing.

6. The method for preparing an all-inorganic perovskite solar cell by quantum dot modification as described in claim 5, characterized in that, The annealing temperature is below 200°C and the annealing time is between 30 minutes and 2 hours to obtain the final quantum dots. The molar ratio of the final quantum dot to the light-absorbing layer is controlled at 0.02-0.006:1, and the thickness of the light-absorbing layer is 500-2000 nanometers.

7. The method for preparing an all-inorganic perovskite solar cell by quantum dot modification as described in claim 2, characterized in that, In step seven, the metal film electrode is prepared by atomic layer deposition and its thickness is controlled between 20-300 nm. The composition is one or more of gold, silver, copper, and titanium. In step eight, the device is annealed in an inert atmosphere at a temperature of 250-500°C for 1 hour. During the annealing process, volatile organic compounds in the light-absorbing layer are further removed.

8. An all-inorganic perovskite solar cell prepared by the method for preparing all-inorganic perovskite solar cells by quantum dot modification according to any one of claims 1 to 7, comprising: The structure comprises a substrate, a hole transport layer, a light-absorbing layer, an electron transport layer, and a cathode. The upper surface of the light-absorbing layer is modified with an inorganic quantum dot layer with a size of less than 10 nanometers. The quantum dot layer is composed of monodisperse CsPbBr3 quantum dots. The light-absorbing layer is an all-inorganic perovskite CsPbI2Br, and the surface modification layer is a pre-prepared quantum dot material. The quantum dot material and the light-absorbing layer material are coated and encapsulated together.

9. A drone, characterized in that, The drone is equipped with the all-inorganic perovskite solar cell as described in claim 8.

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