Preparation method of perovskite thin film, perovskite thin film and perovskite solar cell

Abstract

The invention relates to the technical field of solar cells, in particular to a preparation method of a perovskite thin film, which comprises the following steps: sequentially carrying out ultrasonic cleaning on etched transparent conductive glass by using a preset solution, drying in a forced air drying oven, and carrying out ultraviolet ozone treatment to obtain a transparent conductive oxide substrate; placing the transparent conductive oxide substrate in a glove box in a nitrogen atmosphere to prepare a hole transport layer; adding the perovskite precursor material into a corresponding solvent in a preset proportion, and then stirring and oscillating to obtain a perovskite precursor solution; and spin-coating the perovskite precursor solution on the hole transport layer by using a spin coater, dropwise adding an anti-solvent during spin-coating, and placing the obtained perovskite light absorption film layer on a heating stage for annealing after spin-coating is finished, the insulation metal oxide nanoparticles and the self-assembly monomolecular material are doped in the anti-solvent, so that the absorption of incident light by the perovskite thin film is improved, and the defect of the perovskite thin film at the grain boundary is passivated.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a method for preparing a perovskite film, a perovskite film and a perovskite solar cell. Background Art

[0002] As a safe and environmentally friendly new energy, solar energy is becoming one of the renewable energy sources that can replace fossil fuels due to its inexhaustible advantages, and is expected to account for an increasing proportion of the global energy supply in the future. In recent years, solar cells based on organic-inorganic hybrid perovskite materials have developed rapidly. At present, the highest photoelectric conversion efficiency of a single perovskite solar cell is 26.7%, which is very close to the best performance level of silicon-based solar cells. In order to further improve the performance of perovskite solar cells, research can be conducted from the following aspects: 1. Improving the light absorption capacity of perovskite films; 2. Reducing the non-radiative recombination energy loss induced by defects in perovskite films.

[0003] In response to these two aspects, researchers have also developed many technical means in the past, including increasing the thickness of perovskite films, regulating the band gap of perovskite films, introducing chemical passivators such as Lewis acids and bases, and performing field effect passivation at the interface. However, these technical means can only achieve one of the goals and cannot simultaneously take into account improving the light absorption capacity of perovskite films and reducing the defect state density of perovskite films. Therefore, the above technologies still need to be improved and developed. Summary of the invention

[0004] In order to solve the problems that the perovskite film prepared by the above-mentioned prior art has poor light absorption ability and the non-radiative recombination energy loss induced by defects in the perovskite film is large, which is not conducive to improving the photoelectric conversion efficiency, the present invention provides a method for preparing a perovskite film, a perovskite film and a perovskite solar cell.

[0005] The present invention adopts the following technical solutions: A method for preparing a perovskite film comprises the following steps: S1: Preparation of transparent conductive oxide substrate: The etched transparent conductive glass is cleaned with deionized water, acetone, glass cleaning agent, deionized water, and isopropyl alcohol ultrasonically in sequence; dried in a blast drying oven; the dried transparent conductive glass is treated with ultraviolet ozone to obtain a transparent conductive oxide substrate; S2: Preparation of hole transport layer: placing the transparent conductive oxide substrate in a glove box with a nitrogen atmosphere, and preparing a hole transport layer on the transparent conductive oxide substrate by a coating method, wherein the material of the hole transport layer is selected from one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, nickel oxide, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and self-assembled monolayer, and the material preparation method is selected from a solution method; S3: Preparation of a perovskite light absorbing thin film layer: adding a perovskite precursor material to a corresponding solvent in a preset proportion, stirring and oscillating, to obtain a perovskite precursor solution; The perovskite precursor solution is spin-coated onto the hole transport layer by a multi-step continuous spin coating method using a coating machine, an anti-solvent is added dropwise during the spin coating, and after the spin coating, the obtained perovskite light absorption film layer is placed on a hot stage for annealing at a temperature of 100° C. to 300° C.; wherein insulating metal oxide nanoparticles and self-assembled monomolecular materials are doped into the anti-solvent in advance; In some embodiments, in S1, the time intervals for ultrasonic cleaning with deionized water, acetone, glass cleaner, deionized water, and isopropyl alcohol are set to 10-30 min, and the time is the same. The glass is placed in a 60°C forced air drying oven for drying, and the dried transparent conductive glass is treated with ultraviolet ozone for 15 min.

[0006] In some embodiments, in S1, the transparent conductive glass is selected from FTO or ITO conductive glass.

[0007] In some embodiments, in S2, a predetermined self-assembled monomolecular material is selected and added to an ethanol solvent to make the concentration 0.3 mg mL -1 , use a spin coater to evenly apply the solution onto the transparent conductive oxide substrate, the spin coating speed range is 1000-8000rpm, the spin coating time is 30-90s, and after the spin coating is completed, transfer to a hot plate at 80-150°C and heat for 5-30 min.

[0008] In some embodiments, in S2, the spin coating speed is 3000 rpm, the spin coating time is 30 s, and after the spin coating is completed, it is transferred to a 100° C. hot stage and heated for 10 min.

[0009] In some embodiments, in S3, the perovskite precursor material is selected from at least two of lead iodide, lead chloride, lead bromide, iodoformamide, formamide chloride, formamide bromide, methylamine iodine, methylamine chloride, methylamine bromide, cesium iodide, cesium chloride, cesium bromide, rubidium iodide, rubidium chloride, and rubidium bromide and mixed in a preset ratio; the solvent is selected from at least two of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone and mixed in a preset ratio.

[0010] In some embodiments, in S3, the perovskite precursor solution is spin-coated onto the hole transport layer using a coating machine, and an anti-solvent is added dropwise during the spin coating, and the process includes: First, add an appropriate amount of perovskite precursor solution to the hole transport layer, and then turn on the spin coater for spin coating. In the first stage, the speed range is 300-1000 rpm, and the speed increase rate is 200 rpm s -1 In this embodiment, the spin coating speed is set to 1000 r / min and the operation is performed for 10s; the second stage: the speed range is selected from 2000-8000 rpm, and the spin coating speed is set to 5000 r / min in this embodiment, and the speed increase rate is 2000 rpm s -1 ; The total spin coating time range of the first stage and the second stage is set to 30-90s, and 35s in this embodiment; 150 μL of anti-solvent is added 10 s before the end of spin coating, and the amount of anti-solvent is 100 μL to 5 mL, wherein insulating metal oxide nanoparticles and self-assembled monomolecular materials are pre-doped into the anti-solvent, the insulating metal oxide nanoparticles are selected from at least one of aluminum oxide and zirconium oxide, and the self-assembled monomolecular materials are selected from at least one of Me-4PACz, MeO-2PACz, and 2PACz, and the concentration is 0.1 mg mL -1 Up to 5 mg mL -1 .

[0011] The present invention also provides a perovskite film, which is prepared using the above-mentioned perovskite film preparation method.

[0012] The present invention also provides a perovskite solar cell, which comprises the perovskite film. Beneficial Effects

[0013] The present invention discloses a method for preparing a perovskite film, a perovskite film and a perovskite solar cell. Compared with the prior art, the present invention has the following advantages: In the process of preparing the perovskite film, insulating metal oxide nanoparticles (such as Al 2 O 3 ) and self-assembled monomolecular materials (such as Me-4PACz), thereby achieving the coordinated doping of metal oxide nanoparticles and self-assembled monomolecular materials inside the final perovskite film, with metal oxide nanoparticles such as Al2O3 in the range of 5nm-500nm. 2 O 3It can improve the scattering of sunlight in the perovskite light absorption layer, thereby increasing the optical path, thereby increasing the absorption of incident light by the perovskite film; the two-step spin coating process, and the use of different rotation speeds and increase rates can better control the evaporation rate of the perovskite precursor solvent and the thickness of the perovskite film; a part of the added self-assembled monolayer material will be adsorbed on the Al 2 O 3 Surface, due to Al 2 O 3 The nanoparticles are relatively large in mass. After forming the perovskite film, they will spontaneously accumulate at the bottom interface of the perovskite. High-efficiency inverse-structure perovskite solar cells can be prepared without pre-depositing a hole transport layer. At the same time, the unadsorbed self-assembled monolayer materials cannot enter the perovskite lattice due to their large molecular size, so most of them are enriched at the grain boundaries. The specific functional groups contained in the self-assembled monolayer materials will passivate the defects of the perovskite film at the grain boundaries. The experiment found that the photoelectric conversion efficiency of the control device based on the untreated perovskite film was 24.16%, with an open circuit voltage of 1.13 V and a short-circuit current density of 25.38 mA cm -2 , the filling factor is 84%, and the average photoelectric conversion efficiency of 15 "control" devices prepared in the same batch is 23.10%; while the photoelectric conversion efficiency of the target "target" device of the present invention, which incorporates insulating metal oxide nanoparticles and self-assembled monolayer materials in the antisolvent, is 24.81%, with an open circuit voltage of 1.15 V and a short circuit current density of 25.80 mA cm -2 , the filling factor is 84%, and the average photoelectric conversion efficiency of the 15 "target" devices prepared in the same batch is 24.20%; the short-circuit current density of the prepared inverse-structure perovskite solar cells is improved, the filling factor is also improved, and the final photoelectric conversion efficiency is also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings: Figure 1 A flow chart of a method for preparing a perovskite film provided in an embodiment of the present invention; Figure 2 A schematic diagram of a structure formed during the preparation process of a perovskite film provided in an embodiment of the present invention; Figure 3 JV curves of Control and Target perovskite cells. DETAILED DESCRIPTION

[0015] The following is a description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0016] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0017] like Figure 1 - Figure 3 As shown, the technical solution of the present invention: A method for preparing a perovskite film comprises the following steps: S1: Preparation of transparent conductive oxide substrate: The etched transparent conductive glass is cleaned with deionized water, acetone, glass cleaning agent, deionized water, and isopropyl alcohol ultrasonically in sequence; dried in a blast drying oven; the dried transparent conductive glass is treated with ultraviolet ozone to obtain a transparent conductive oxide substrate; S2: Preparation of hole transport layer: placing the transparent conductive oxide substrate in a glove box with a nitrogen atmosphere, and preparing a hole transport layer on the transparent conductive oxide substrate by a coating method; the material of the hole transport layer is selected from one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, nickel oxide, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and self-assembled monolayer, and the material preparation method is selected from a solution method; S3: Preparation of a perovskite light absorbing thin film layer: adding a perovskite precursor material to a corresponding solvent in a preset proportion, stirring and oscillating, to obtain a perovskite precursor solution; The perovskite precursor solution is spin-coated onto the hole transport layer using a multi-step continuous spin coating method using a coater, and an anti-solvent is added during the spin coating. After the spin coating is completed, the obtained perovskite light absorption film layer is placed on a hot stage for annealing at a temperature of 100° C. to 300° C. wherein insulating metal oxide nanoparticles and self-assembled monomolecular materials are doped into the anti-solvent in advance.

[0018] The preferred embodiments disclosed in the present invention are as follows: Figure 1-Figure 3 As shown: The present invention discloses a method for preparing a perovskite film, comprising the following steps: S1: Preparation of transparent conductive oxide substrate: The etched transparent conductive glass is ultrasonically cleaned with deionized water, acetone, glass cleaning agent, deionized water, and isopropanol in sequence. FTO or ITO conductive glass is usually selected. In this embodiment, FTO transparent conductive glass is selected. The ultrasonic cleaning time is set to 10-30 min. In this embodiment, the ultrasonic cleaning time is set to 10 min. After the ultrasonic cleaning is completed, it is placed in a 60°C blast drying oven for drying. The dried transparent conductive glass is treated with ultraviolet ozone for 15 min to obtain a transparent conductive oxide substrate; S2: Preparation of hole transport layer: The FTO transparent conductive oxide substrate is placed in a glove box with a nitrogen atmosphere, wherein the water and oxygen content in the glove box is less than 0.01 ppm, and a hole transport layer is prepared on the transparent conductive oxide substrate, wherein the material of the hole transport layer is selected from one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, nickel oxide, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and a self-assembled monolayer, and the material preparation method includes a solution method, a sol-gel method, a magnetron sputtering method, an atomic layer deposition method, and a combustion method. In this embodiment, the solution method is preferred, and the self-assembled monolayer is selected, and the material is MeO-2PACz, and the concentration is 0.3 mg mL -1 , the solvent is ethanol; a spin coater, a slit coater, a doctor blade coater, and an inkjet printer can be used. In this embodiment, a LEBO spin coater is used, and a preset self-assembled monomolecular material is selected and added to the ethanol solvent to make the concentration 0.3 mg mL -1 , use a spin coater to evenly apply the solution onto the transparent conductive oxide substrate, the spin coating speed range is 1000-8000 rpm, the spin coating time is 30-90 s, the spin coating speed is 3000 rpm, the spin coating time is 30 s, after the spin coating is completed, transfer to a hot plate at 80-150°C and heat for 5-30 min, and in this embodiment, transfer to a hot plate at 100°C and heat for 10 min after the spin coating is completed.

[0019] S3: Preparation of perovskite light absorbing thin film layer: First, the perovskite precursor material includes lead iodide (PbI 2 )、Lead chloride (PbCl 2 ), lead bromide (PbBr 2), at least two of formamidine iodide (FAI), formamidine chloride (FACl), formamidine bromide (FABr), methylamine iodide (MAI), methylamine chloride (MACl), methylamine bromide (MABr), cesium iodide (CsI), cesium chloride (CsCl), cesium bromide (CsBr), rubidium iodide (RbI), rubidium chloride (RbCl), and rubidium bromide (RbBr), are mixed according to a preset ratio; a corresponding solvent is added, and the solvent is selected from at least two of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP), and mixed according to a preset ratio; the two mixed solutions are mixed according to a preset ratio, and stirred and shaken to obtain a perovskite precursor solution.

[0020] The perovskite precursor materials selected in this embodiment are cesium iodide (CsI), formamidine iodide (FAI), lead iodide (PbI 2 ), lead bromide (PbBr 2 ), the solution concentration is 1.5 M, 0.075 mmol cesium iodide, 1.425 mmol iodomethane, 1.425 mmol lead iodide, 0.075 mmol lead bromide are mixed together; the added solvent is DMF:DMSO, the ratio is 4:1; after stirring and shaking, the perovskite precursor solution (Cs 0.05 FA 0.95 Pb(Br 0.05 I 0.95 ) 3 ).

[0021] The perovskite precursor solution is spin-coated onto the FTO transparent conductive oxide substrate using a spin coating machine, using a multi-step spin coating process, and an anti-solvent is added dropwise during the spin coating, the process comprising: Step 1: First, add an appropriate amount of perovskite precursor solution to the hole transport layer, and then turn on the spin coater for spin coating. The spin coating speed range is 300-1000 rpm, and the speed increase rate is 200 rpm s -1 , in this embodiment, 1000 rpm and time are 10 s; Step 2: Spin coating speed range is 2000-8000 rpm, and the speed increase rate is 2000 rpm s -1 , in this embodiment, 5000 rpm is used, the total spin coating time range of the first step and the second step is set to 30-90s, and the total spin coating time in this embodiment is 35s; 10 s before the end of spin coating, the anti-solvent pre-doped with insulating metal oxide nanoparticles and self-assembled monomolecular materials is added dropwise, the amount of the anti-solvent is 100 microliters to 5 milliliters, and the anti-solvent selected in this embodiment is chlorobenzene, and the amount of anti-solvent chlorobenzene added is 150 μL.

[0022] The insulating metal oxide nanoparticles are selected from at least one of aluminum oxide and zirconium oxide, and the self-assembled monomolecular material is selected from at least one of Me-4PACz, MeO-2PACz, and 2PACz. In this embodiment, 1 mg mL -1 Aluminum oxide (Al 2 O 3 ) nanoparticles and 0.1 mg mL -1 2PACz.

[0023] The present invention adopts a two-step spin coating method and adopts different rotation speeds and increasing rates, which can better regulate the volatilization rate of the perovskite precursor solvent and regulate the thickness of the perovskite film.

[0024] After the spin coating is completed, the obtained perovskite light absorbing film layer is placed on a hot stage for annealing at a temperature of 100° C. to 300° C. In this embodiment, the perovskite light absorbing film layer is placed on a hot stage at a temperature of 100° C. and heated for 30 min. Figure 1 , Figure 2 shown.

[0025] Perovskite solar cells are manufactured using a conventional method using a perovskite film.

[0026] Figure 3 1 is a JV curve diagram of the perovskite film according to an embodiment of the present invention and a JV curve diagram of an untreated perovskite film.

[0027] The experiment found that the photoelectric conversion efficiency of the control device based on the untreated perovskite film was 24.16%, with an open circuit voltage of 1.13 V and a short circuit current density of 25.38 mA cm -2 , the fill factor is 84%; the average photoelectric conversion efficiency of 15 "control" devices prepared in the same batch is 23.10%.

[0028] In this embodiment, the photoelectric conversion efficiency of the Target device doped with insulating metal oxide nanoparticles and self-assembled monolayer materials in the antisolvent is 24.81%, with an open circuit voltage of 1.15 V and a short circuit current density of 25.80 mA cm -2 , the filling factor is 84%, and the average photoelectric conversion efficiency of the 15 "target" devices prepared in the same batch is 24.20%; the short-circuit current density of the prepared inverse-structure perovskite solar cells is improved, the filling factor is also improved, and the final photoelectric conversion efficiency is also improved.

[0029] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for preparing a perovskite film, characterized in that: The steps include: S1: Preparation of transparent conductive oxide substrate: The etched transparent conductive glass is cleaned with deionized water, acetone, glass cleaning agent, deionized water, and isopropyl alcohol ultrasonically in sequence; dried in a blast drying oven; the dried transparent conductive glass is treated with ultraviolet ozone to obtain a transparent conductive oxide substrate; S2: Preparation of hole transport layer: placing the transparent conductive oxide substrate in a glove box with a nitrogen atmosphere, and preparing a hole transport layer on the transparent conductive oxide substrate by a coating method; the material of the hole transport layer is selected from one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, nickel oxide, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and self-assembled monolayer, and the material preparation method is selected from a solution method; S3: Preparation of a perovskite light absorbing thin film layer: adding a perovskite precursor material to a corresponding solvent in a preset proportion, stirring and oscillating, to obtain a perovskite precursor solution; The perovskite precursor solution is spin-coated onto the hole transport layer using a multi-step continuous spin coating method using a coater, and an anti-solvent is added during the spin coating. After the spin coating is completed, the obtained perovskite light absorption film layer is placed on a hot stage for annealing at a temperature of 100° C. to 300° C. wherein insulating metal oxide nanoparticles and self-assembled monomolecular materials are doped into the anti-solvent in advance.

2. The method for preparing a perovskite thin film according to claim 1, characterized in that: In S1, the time intervals for ultrasonic cleaning with deionized water, acetone, glass cleaning agent, deionized water, and isopropanol are set to 10-30 min respectively, and the cleaning time is the same. The glass is placed in a 60°C forced air drying oven for drying, and the dried transparent conductive glass is treated with ultraviolet ozone for 15 min.

3. The method for preparing a perovskite thin film according to claim 1, characterized in that: In S1, the transparent conductive glass is selected from FTO or ITO conductive glass.

4. The method for preparing a perovskite thin film according to claim 1, characterized in that: In S2, select the preset self-assembled monomolecular material and add ethanol solvent to make the concentration 0.3 mg mL -1 , use a spin coater to evenly apply the solution onto the transparent conductive oxide substrate, the spin coating speed range is 1000-8000rpm, the spin coating time is 30-90s, and after the spin coating is completed, transfer to a hot plate at 80-150°C and heat for 5-30 min.

5. The method for preparing a perovskite thin film according to claim 4, characterized in that: In S2, the spin coating speed was 3000 rpm, the spin coating time was 30 s, and after the spin coating was completed, it was transferred to a 100°C hot stage and heated for 10 min.

6. The method for preparing a perovskite thin film according to claim 1, characterized in that: In S3, the perovskite precursor materials are selected from at least two of lead iodide, lead chloride, lead bromide, iodomethane, methylammonium chloride, methylammonium bromide, methylamine iodide, methylamine chloride, methylamine bromide, cesium iodide, cesium chloride, cesium bromide, rubidium iodide, rubidium chloride, and rubidium bromide and mixed in a preset ratio; the solvent is selected from at least two of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone and mixed in a preset ratio.

7. The method for preparing a perovskite thin film according to claim 1, characterized in that: In S3, the perovskite precursor solution is spin-coated onto the hole transport layer using a coating machine, and an anti-solvent is added dropwise during the spin coating. The process includes: First, add an appropriate amount of perovskite precursor solution to the hole transport layer, and then turn on the spin coater for spin coating. In the first stage, the speed range is 300-1000 rpm, and the speed increase rate is 200 rpm s -1 , time is 10s; second stage: the speed range is 2000-8000 rpm, and the speed increase rate is 2000 rpm s -1 The total spin coating time range of the first stage and the second stage is set to 30-90s, and 150 μL of anti-solvent is added 10 s before the end of spin coating. The amount of anti-solvent is 100 microliters to 5 milliliters, wherein insulating metal oxide nanoparticles and self-assembled monomolecular materials are pre-doped into the anti-solvent, and the insulating metal oxide nanoparticles are selected from at least one of aluminum oxide and zirconium oxide, and the self-assembled monomolecular materials are selected from at least one of Me-4PACz, MeO-2PACz, and 2PACz, and the concentration is 0.1 mg mL -1 Up to 5 mg mL -1 .

8. The method for preparing a perovskite thin film according to claim 7, characterized in that: In S3, the multi-step continuous spin coating process includes: Step 1: First, add an appropriate amount of perovskite precursor solution onto the hole transport layer, then turn on the spin coater for spin coating. The spin coating speed is 1000 r / min and the speed increase rate is 200 rpm s -1 , run for 10s; Step 2: Spin coating at a speed of 5000 r / min and a speed increase rate of 2000 rpm s -1 , the total spin coating time of the first step and the second step is 35s; 10s before the end of the spin coating, the anti-solvent doped with insulating metal oxide nanoparticles and self-assembled monomolecular materials is added dropwise, the anti-solvent is chlorobenzene, and the amount of anti-solvent chlorobenzene added is 150 μL; Among them, 1 mg mL -1 Al2O3 nanoparticles and 0.1mg mL -1 2PACz.

9. A perovskite film, characterized in that: It is prepared using the method for preparing a perovskite film according to any one of claims 1 to 8.

10. A perovskite solar cell, characterized in that: It comprises the perovskite film according to claim 9.

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