Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof. The preparation method comprises the following steps: providing a conductive substrate; preparing an electron transport layer on the conductive substrate; preparing a three-dimensional perovskite layer on the surface of the electron transport layer; coating the surface of the three-dimensional perovskite layer with a 1, 3-dimethylimidazolium dimethyl phosphate solution, and carrying out first annealing treatment to obtain a one-dimensional passivation layer containing an imidazole ring; preparing a hole transport layer on the surface of the one-dimensional passivation layer containing the imidazole ring; and preparing an electrode on the surface of the hole transport layer. According to the invention, 1, 3-dimethylimidazolium dimethyl phosphate is introduced to the surface of the three-dimensional perovskite layer to promote the formation of one-dimensional perovskite containing an imidazole ring, so that the creation of the method not only can improve the photovoltaic performance of the perovskite solar cell, but also has excellent long-term stability; and the perovskite solar cell can be promoted to proceed towards the directions of large-scale production and commercial application.

Description

Technical Field

[0001] The present invention relates to the field of solar energy preparation technology, and in particular to a perovskite solar cell and a preparation method thereof. Background Art

[0002] In recent years, three-dimensional perovskite materials have attracted much attention due to their excellent luminescence properties, diverse components, low cost, suitability for solution processing, and large-area film formation. These advantages have enabled them to show a wide range of application prospects in the optoelectronic field. Traditional three-dimensional perovskite solar cells have achieved an impressive photoelectric conversion efficiency of 25.7%.

[0003] However, long-term stability has become the main challenge facing current three-dimensional perovskite solar cells. This is because three-dimensional perovskite materials are prone to ion migration, resulting in structural instability. In addition, it has relatively poor tolerance to ultraviolet light, oxygen, humidity, high temperature and electric fields in the surrounding environment, resulting in a sharp shortening of the life of three-dimensional perovskite solar cells, which has become a bottleneck limiting its practical application. Therefore, while ensuring the photovoltaic performance of perovskite solar cells, improving the long-term stability of solar cells has become a research focus.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a perovskite solar cell and a preparation method thereof to solve the problem of insufficient stability of existing three-dimensional perovskite solar cells.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0007] A first aspect of the present invention provides a method for preparing a perovskite solar cell, comprising the following steps:

[0008] providing a conductive substrate;

[0009] preparing an electron transport layer on the conductive substrate;

[0010] Preparing a three-dimensional perovskite layer on the surface of the electron transport layer;

[0011] Coating a 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, and performing a first annealing treatment to obtain a one-dimensional passivation layer containing imidazole rings;

[0012] Preparing a hole transport layer on the surface of the one-dimensional passivation layer containing imidazole rings;

[0013] An electrode is prepared on the surface of the hole transport layer.

[0014] Preferably, coating a 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer and performing a first annealing treatment to obtain a one-dimensional passivation layer containing imidazole rings specifically comprises:

[0015] dissolving 1,3-dimethylimidazolium dimethyl phosphate in an organic solvent to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution;

[0016] The 1,3-dimethylimidazolium dimethyl phosphate solution is spin-coated on the surface of the three-dimensional perovskite layer, and a first annealing treatment is performed at a temperature of 90 to 150° C. for 1 to 10 minutes to obtain the one-dimensional passivation layer containing imidazole rings.

[0017] Preferably, in the 1,3-dimethylimidazolium dimethyl phosphate solution, the concentration of 1,3-dimethylimidazolium dimethyl phosphate is 0.1-2 mg / mL.

[0018] Preferably, in the step of spin coating the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, the spin coating speed is 1000 to 5000 r / s, and the spin coating time is 20 to 60 s.

[0019] Preferably, the step of preparing a three-dimensional perovskite layer on the surface of the electron transport layer specifically comprises:

[0020] providing a lead iodide solution and an organic cation solution;

[0021] Spin coating the lead iodide solution on the surface of the electron transport layer and performing a second annealing treatment to obtain a lead iodide layer;

[0022] The organic cation solution is spin-coated on the surface of the lead iodide layer, and a third annealing treatment is performed to obtain the three-dimensional perovskite layer.

[0023] Preferably, in the step of spin coating the lead iodide solution on the surface of the electron transport layer, the spin coating speed is 500 to 3000 r / s, and the spin coating time is 20 to 60 s;

[0024] And / or; the temperature of the second annealing treatment is 50-100°C and the time is 20-100s.

[0025] Preferably, in the step of spin coating the organic cationic solution on the surface of the lead iodide layer, the spin coating speed is 500 to 3000 r / s, and the spin coating time is 20 to 60 s;

[0026] And / or; the temperature of the third annealing treatment is 80-150°C, the humidity is 10-40%, and the time is 40-80 minutes.

[0027] Preferably, in the organic cationic solution, the solute is selected from one or more of formamidine, methylamine hydroiodide, methylamine hydrochloride, and methylamine hydrobromide.

[0028] A second aspect of the present invention provides a perovskite solar cell prepared by the above-mentioned preparation method.

[0029] Beneficial effects:

[0030] The present invention introduces 1,3-dimethylimidazolium dimethyl phosphate on the surface of the three-dimensional perovskite layer to promote the formation of a one-dimensional perovskite containing an imidazole ring. The one-dimensional perovskite containing the imidazole ring can effectively passivate defects, while regulating the energy level arrangement, and promoting the transfer and extraction of charges. In addition, the hydrophobicity of the one-dimensional perovskite containing the imidazole ring helps to improve the stability of the mixed-dimensional perovskite of the present invention. The strong chemical reaction between the imidazole ring and the perovskite can effectively inhibit the migration of ions in the three-dimensional perovskite layer and slow down the degradation of the perovskite. The 1,3-dimethylimidazolium dimethyl phosphate introduced by the present invention can not only improve the photovoltaic performance of the device, but also has excellent long-term stability, which helps to promote perovskite photovoltaic devices towards large-scale production and commercial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is an optical image of a one-dimensional perovskite single crystal prepared in Example 1 of the present invention;

[0032] Figure 2 The scanning electron microscope images of the one-dimensional perovskite modified three-dimensional perovskite layer containing imidazole rings prepared in Example 1 of the present invention and the three-dimensional perovskite layer prepared in the control group;

[0033] Figure 3 A comparison chart of the photoelectric conversion efficiency of the perovskite solar cells prepared in Example 1 of the present invention and the control group;

[0034] Figure 4 Contact angle test graphs of the one-dimensional perovskite-modified three-dimensional perovskite layer containing imidazole rings prepared in Example 1 of the present invention and the three-dimensional perovskite layer prepared in the control group. DETAILED DESCRIPTION

[0035] The present invention provides a perovskite solar cell and a method for preparing the same. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] The excess lead iodide remaining on the surface of the three-dimensional perovskite layer makes existing three-dimensional perovskite solar cells unstable.

[0037] Based on this, the present invention provides a method for preparing a perovskite solar cell, comprising the following steps:

[0038] providing a conductive substrate;

[0039] preparing an electron transport layer on the conductive substrate;

[0040] Preparing a three-dimensional perovskite layer on the surface of the electron transport layer;

[0041] coating a 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, and performing a first annealing treatment to obtain a one-dimensional passivation layer containing imidazole rings;

[0042] Preparing a hole transport layer on the surface of the one-dimensional passivation layer containing imidazole rings;

[0043] An electrode is prepared on the surface of the hole transport layer.

[0044] The present invention uses 1,3-dimethylimidazolium dimethyl phosphate to modify the three-dimensional perovskite layer, and obtains a one-dimensional passivation layer containing imidazole rings on the surface of the three-dimensional perovskite layer. 1,3-dimethylimidazolium dimethyl phosphate can combine with the lead iodide remaining on the surface of the three-dimensional perovskite layer to form a one-dimensional perovskite containing imidazole rings, reducing the residual lead iodide and thus improving stability; and the one-dimensional perovskite containing imidazole rings has better hydrophobicity than the three-dimensional perovskite, and thus has stronger resistance to water. Furthermore, there is a strong chemical interaction between the one-dimensional perovskite containing imidazole rings and the three-dimensional perovskite, which can passivate defects on the one hand and effectively inhibit the migration of ions on the other hand, combined with the reduction of residual lead iodide, thereby significantly improving the stability of the perovskite solar cell from many aspects; finally, the one-dimensional perovskite containing imidazole rings can passivate the defects of the three-dimensional perovskite and regulate the energy level, which can significantly improve the transfer of charges and reduce non-radiative recombination, thereby further improving the photoelectric conversion efficiency. Combined with the enhanced stability, the perovskite solar cell prepared by the present invention has high efficiency and stable properties.

[0045] In the step of providing a conductive substrate, in some embodiments, the conductive substrate is a rigid conductive glass substrate or a flexible conductive film substrate. Further, the rigid conductive glass substrate may be, but is not limited to, one of an ITO substrate and a FTO substrate. Further, the flexible conductive film substrate may be, but is not limited to, one of a PET substrate and a PEN substrate.

[0046] In some embodiments, the conductive substrate is a conductive substrate that has been cleaned and treated with ultraviolet ozone. Specifically, the conductive substrate is first cleaned, and then the cleaned conductive substrate is treated with ultraviolet ozone. Further, the cleaning step is: ultrasonically cleaning the conductive substrate with a detergent aqueous solution, deionized water and isopropanol in sequence, and then drying with nitrogen.

[0047] In the step of preparing an electron transport layer on the conductive substrate, in some embodiments, specifically includes:

[0048] preparing an electron transport material solution;

[0049] The electron transport material solution is coated on the conductive substrate by a solution method (such as spin coating, spray coating, chemical bath, etc.), and then annealed to obtain the electron transport layer.

[0050] In some embodiments, the electron transport material solution may be an organic electron transport material solution, such as a PCBM solution or a C 60 solution etc.

[0051] In some embodiments, the electron transport material solution may be an inorganic electron transport material solution, such as a titanium dioxide solution or a tin dioxide solution.

[0052] In some embodiments, in the 1,3-dimethylimidazolium dimethyl phosphate solution, the concentration of 1,3-dimethylimidazolium dimethyl phosphate is 0.1-2 mg / mL. The concentration of 1,3-dimethylimidazolium dimethyl phosphate can be 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, or 2 mg / mL.

[0053] The present invention controls the concentration of 1,3-dimethylimidazolium dimethyl phosphate within 0.1 to 2 mg / mL because a suitable amount of one-dimensional perovskite can be formed within this range. When the concentration is less than 0.1 mg / mL, the one-dimensional perovskite is small, so that the performance improvement efficiency is not obvious. When the concentration is greater than 2 mg / mL, it will lead to too many one-dimensional perovskites. Although the stability is improved, the efficiency is reduced. Between 0.1 and 2 mg / mL, the photoelectric conversion efficiency and stability of the device are improved.

[0054] In some preferred embodiments, the concentration of 1,3-dimethylimidazolium dimethyl phosphate is 0.5 mg / mL. At this concentration, the photoelectric conversion efficiency and stability of the device are most significantly improved.

[0055] In some embodiments, in the step of spin coating the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, the spin coating speed is 1000-5000 r / s, and the spin coating time is 20-60 s; the spin coating speed can be 1000 r / s, 2000 r / s, 3000 r / s, 4000 r / s, 5000 r / s, and the spin coating time can be 20 s, 30 s, 40 s, 50 s, 60 s;

[0056] And / or: the temperature of the first annealing treatment is 90-150°C, and the time is 1-10 min. The temperature of the first annealing treatment can be 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, and the time can be 1 min, 5 min, 10 min.

[0057] Within this annealing temperature and time range, a one-dimensional perovskite passivation layer with good performance can be formed. When the temperature is lower than 100°C and the annealing time is less than 5 minutes, an ideal perovskite crystal cannot be formed. Too high a temperature or too long an annealing time will destroy the effect of the one-dimensional perovskite passivation layer.

[0058] In some preferred embodiments, in the step of spin coating the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, the spin coating speed is 4000 r / s and the spin coating time is 30 s;

[0059] And / or; the temperature of the first annealing treatment is 100°C and the time is 5 minutes.

[0060] In the step of preparing a hole transport layer on the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate, in some embodiments, specifically includes:

[0061] preparing a hole transport material solution;

[0062] The hole transport material solution is coated on the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate by a solution method (such as spin coating, blade coating, chemical bath, etc.), and the hole transport layer is obtained by annealing.

[0063] In some embodiments, the hole transport material solution may be an organic hole transport material solution, such as a PEDOT:PSS solution or a Sprio-OMeTAD solution.

[0064] In some embodiments, the hole transport material solution may be an inorganic hole transport material solution, such as a nickel oxide solution or a cuprous thiocyanate solution.

[0065] In the step of preparing an electrode on the surface of the hole transport layer, in some embodiments, specifically includes: a vacuum spraying device can be used to spray an 80nm metal electrode on the surface of the hole transport layer.

[0066] In some embodiments, the step of preparing a three-dimensional perovskite layer on the surface of the electron transport layer specifically comprises the following steps:

[0067] providing a lead iodide solution and an organic cation solution;

[0068] Spin coating the lead iodide solution on the surface of the electron transport layer and performing a second annealing treatment to obtain a lead iodide layer;

[0069] The organic cation solution is spin-coated on the surface of the lead iodide layer, and a third annealing treatment is performed to obtain the three-dimensional perovskite layer.

[0070] In some embodiments, in the step of spin coating the lead iodide solution on the surface of the electron transport layer, the spin coating speed is 500 to 3000 r / s, and the spin coating time is 20 to 60 s; the spin coating speed can be 500 r / s, 1000 r / s, 1500 r / s, 2000 r / s, 2500 r / s, 3000 r / s, and the spin coating time can be 20 s, 30 s, 40 s, 50 s, 60 s;

[0071] and / or; the temperature of the second annealing treatment is 50-100°C, and the time is 20-100s. The temperature of the second annealing treatment can be 50°C, 60°C, 75°C, 80°C, 90°C, 100°C, and the time can be 20s, 30s, 40s, 50s, 60s.

[0072] The present invention sets the temperature of the second step annealing treatment to 50-100°C, because if the annealing temperature is too low, the solvent will not volatilize, affecting film formation; if the temperature is too high, the intermediate phase will be destroyed. The time of the second step annealing treatment is limited to 20-100s, because if the time is too short, the solution coating will be uneven, and the film is already very uniform at 60s.

[0073] In some embodiments, the solvent of the lead iodide solution may be, but is not limited to, one or more of dimethyl sulfoxide, N,N-dimethylformamide, r-butyrolactone, and N-methylpyrrolidone.

[0074] In some preferred embodiments, in the step of spin coating the lead iodide solution on the surface of the electron transport layer, the spin coating speed is 1500 r / s and the spin coating time is 30 s;

[0075] And / or; the temperature of the second annealing treatment is 75°C and the time is 60s.

[0076] In some embodiments, in the step of spin coating the organic cationic solution on the surface of the lead iodide layer, the spin coating speed is 500-3000 r / s, and the spin coating time is 20-60 s; the spin coating speed can be 500 r / s, 1000 r / s, 1300 r / s, 1700 r / s, 2000 r / s, 2200 r / s, 2600 r / s, 3000 r / s, and the spin coating time can be 20 s, 30 s, 40 s, 50 s, 60 s.

[0077] And / or; The temperature of the third annealing treatment is 80-150°C, the humidity is 10-40%, and the time is 40-80 min. The temperature of the third annealing treatment can be 80°C, 90°C, 100°C, 120°C, 135°C, 150°C, the humidity can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, and the time can be 40min, 50min, 60min, 70min, 80min.

[0078] The temperature of the third annealing treatment in the present invention is 80-150°C. This is because a higher temperature will cause the degradation of perovskite at high temperature, and a lower temperature is not conducive to the crystallization of perovskite. The present invention also performs annealing in a closed environment with different humidity, and sets the humidity to 10-40%. Humidity mainly affects the crystallinity of perovskite.

[0079] In some preferred embodiments, in the step of spin coating the organic cation solution on the surface of the lead iodide layer, the spin coating speed is 1700 r / s and the spin coating time is 30 s;

[0080] And / or; the temperature of the third annealing treatment is 135°C, the humidity is 15%, and the time is 60 minutes.

[0081] In some embodiments, in the organic cation solution, the solute is selected from one or more of formamidine, methylamine hydroiodide, methylamine hydrochloride, and methylamine hydrobromide, and the solute is isopropanol.

[0082] An embodiment of the present invention provides a perovskite solar cell prepared by the above-mentioned preparation method.

[0083] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are only used to illustrate the present invention but not to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0084] Example 1

[0085] A method for preparing a perovskite solar cell comprises the following steps:

[0086] Cleaning and UV-ozone treatment of ITO substrate: Place the ITO substrate in a beaker, ultrasonically clean it in a detergent aqueous solution for 15 minutes, then ultrasonically clean it in deionized water for 15 minutes, and finally ultrasonically clean it in isopropanol for 15 minutes, and then blow dry it with nitrogen. Place the cleaned ITO substrate in a UV instrument and treat it with ozone for 30 minutes.

[0087] Prepare a tin dioxide electron transport layer (50 nm) by spin coating: prepare a tin dioxide solution (use deionized water to dilute the tin dioxide solution, the volume ratio of the tin dioxide solution to the deionized water solution is 1:5). Set the parameters of the spin coater: the spin coating speed is 4000 rpm / s, the acceleration is 4000 rpm / s 2 , run for 30 seconds. Drop the tin dioxide solution on the surface of the UV-treated ITO substrate, start the spin coater, and after the spin coating is completed, place the sample on a heating table and anneal at 150°C for 30 minutes.

[0088] A two-step method for preparing a three-dimensional perovskite layer (700nm): ① Prepare a solution for the perovskite active layer: Dissolve 1.5 mol of lead iodide in 1 mL of DMF solution to obtain a lead iodide solution; dissolve FAI, MACl, and MABr in an IPA solution, stir evenly, and obtain an organic cation solution, wherein the mass concentrations of FAI, MACl, and MABr are 60 mg / mL, 6 mg / mL, and 6 mg / mL, respectively. ② Preparation of the perovskite active layer: In the first step, the ITO substrate with an electron transport layer on the surface is UV treated for 30 minutes. Set the parameters of the spin coater: the rotation speed is 1500 rpm / s, the acceleration is 1500 rpm / s 2 , run for 30 seconds. Drop the lead iodide solution on the surface of the electron transport layer and turn on the spin coater. After the spin coating is completed, anneal at 70℃ for 60 seconds and then cool for use. Step 2, add the organic cation solution based on the first step, and the spin coater parameters are the same as the first step. After the spin coating is completed, place the sample on the heating table, anneal at 100℃ for 50 minutes, and then cool for use.

[0089] A one-dimensional passivation layer (80 nm) containing imidazole rings was prepared by spin coating: 1,3-dimethylimidazolium dimethyl phosphate was dissolved in IPA to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution with a concentration of 0.5 mg / mL, and the parameters of the spin coater were set: the rotation speed was 4000 r / s, and the operation was performed for 30 s. Then, the 1,3-dimethylimidazolium dimethyl phosphate solution was dropped on the surface of the three-dimensional perovskite layer and the spin coater was turned on. After the spin coating was completed, annealing was performed at 100°C for 5 min.

[0090] Prepare the sprio-OMeTAD hole transport layer (200 nm) by spin coating: Spin coating with spiro-OMeTAD solution. The preparation of spiro-OMeTAD solution is as follows: 72.5 mg spiro-OMeTAD, 36 uL TBP, 30 uL LiTFSI solution (solvent is acetonitrile, LiTFSI 260 mg, acetonitrile 1 mL) are mixed in 1 mL chlorobenzene. Set the parameters of the spin coater: the speed is 4000 rpm / s, the acceleration is 4000 rpm / s 2 , run for 30 seconds. Drop the spiro-OMeTAD solution on the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate, turn on the spin coater, and stand in the dark for 12 hours after spin coating to obtain a hole transport layer.

[0091] A gold electrode with a thickness of about 80 nm was evaporated on the surface of the hole transport layer to obtain a perovskite solar cell, and the optical image of its one-dimensional perovskite single crystal is shown in Figure 1.

[0092] Example 2

[0093] A method for preparing a perovskite solar cell comprises the following steps:

[0094] Cleaning and UV-ozone treatment of FTO substrate: Place the FTO substrate in a beaker, ultrasonically clean it in deionized water and detergent solution for 30 minutes, then ultrasonically clean it in deionized water for 30 minutes, and finally ultrasonically clean it in isopropanol for 30 minutes, and then blow dry it with nitrogen. Place the cleaned FTO substrate in a UV instrument and treat it with ozone for 30 minutes.

[0095] Prepare the tin dioxide electron transport layer by spin coating: prepare tin dioxide solution (use deionized water to dilute the tin dioxide solution, the volume ratio of tin dioxide solution to deionized water solution is 1:6). Set the parameters of the spin coater: the spin coating speed is 3000rpm / s, the acceleration is 3000rpm / s 2 , run for 30 seconds. Drop the tin dioxide solution on the surface of the FTO substrate after UV treatment, start the spin coater, and after the spin coating is completed, place the sample on a heating table and anneal at 180°C for 60 minutes.

[0096] Two-step spin coating to prepare three-dimensional perovskite layer: ① Prepare the solution of perovskite active layer: dissolve 1.5 mol of lead iodide in 1 mL of DMF solution to obtain lead iodide solution; dissolve FAI, MACl, and MABr in IPA solution, stir evenly to obtain an organic cation solution, in which the mass concentrations of FAI, MACl, and MABr are 60 mg / mL, 6 mg / mL, and 6 mg / mL, respectively. ② Preparation of perovskite active layer: Step 1, UV treat the FTO substrate with an electron transport layer on the surface for 30 minutes. Set the parameters of the spin coater: the rotation speed is 1500 rpm / s, the acceleration is 1500 rpm / s 2 , run for 30 seconds. Drop the lead iodide solution on the surface of the electron transport layer and turn on the spin coater. After the spin coating is completed, anneal at 70℃ for 60 seconds and then cool for use. Step 2, add the organic cation solution based on the first step, and the spin coater parameters are the same as the first step. After the spin coating is completed, place the sample on the heating table, anneal at 100℃ for 50 minutes, and then cool for use.

[0097] A one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate was prepared by spin coating process: 1,3-dimethylimidazolium dimethyl phosphate was dissolved in IPA to obtain a 1 mg / mL 1,3-dimethylimidazolium dimethyl phosphate solution, and the parameters of the spin coater were set: the rotation speed was 4000 r / s, and the operation was performed for 30 seconds. Then, the 1,3-dimethylimidazolium dimethyl phosphate solution was dropped on the surface of the three-dimensional perovskite layer and the spin coater was turned on. After the spin coating was completed, annealing was performed at 100°C for 5 minutes.

[0098] Prepare the sprio-OMeTAD hole transport layer by spin coating: Spin coating with spiro-OMeTAD solution. The preparation of spiro-OMeTAD solution is as follows: 72.5 mg spiro-OMeTAD, 36 uL TBP, 30 uL LiTFSI solution (solvent is acetonitrile, LiTFSI 260 mg, acetonitrile 1 mL) are mixed in 1 mL chlorobenzene. Set the parameters of the spin coater: the speed is 4000 rpm / s, the acceleration is 4000 rpm / s 2 , run for 30 seconds. Drop the spiro-OMeTAD solution on the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate, turn on the spin coater, and after spin coating, stand in the dark overnight for oxidation to obtain a hole transport layer.

[0099] A gold electrode with a thickness of about 80 nm is evaporated on the surface of the hole transport layer to obtain a perovskite solar cell.

[0100] Example 3

[0101] A method for preparing a perovskite solar cell comprises the following steps:

[0102] Cleaning and UV-ozone treatment of ITO substrate: Place the ITO substrate in a beaker, ultrasonically clean it in a detergent aqueous solution for 15 minutes, then ultrasonically clean it in deionized water for 15 minutes, and finally ultrasonically clean it in isopropanol for 15 minutes. After completion, blow dry it with nitrogen.

[0103] Prepare the PEDOT:PSS hole transport layer by spin coating: Spin coating with PEDOT:PSS solution. The preparation of PEDOT:PSS solution is as follows: PEDOT:PSS and ethanol are mixed evenly in a volume ratio of 1:3 and filtered using a 45nm filter head. Set the parameters of the spin coater: speed of 4000rpm / s, acceleration of 2000rpm / s2, and run for 60s. Drop the filtered PEDOT:PSS solution on the ITO substrate, turn on the spin coater, anneal at 150℃ for 0.5h after spin coating, and cool it for use.

[0104] Two-step spin coating to prepare three-dimensional perovskite layer: ① Prepare the solution of perovskite active layer: dissolve 1.5 mol of lead iodide in 1 mL of DMF solution to obtain lead iodide solution; dissolve FAI, MACl, and MABr in IPA solution, stir evenly to obtain an organic cation solution, in which the mass concentrations of FAI, MACl, and MABr are 70 mg / mL, 7 mg / mL, and 7 mg / mL, respectively. ② Preparation of perovskite active layer: Step 1, UV treat the ITO substrate with a hole transport layer on the surface for 30 minutes. Set the parameters of the spin coater: the rotation speed is 1500 rpm / s, the acceleration is 1500 rpm / s 2 , run for 30 seconds. Drop the lead iodide solution on the surface of the hole transport layer and turn on the spin coater. After the spin coating is completed, anneal at 70℃ for 60 seconds and then cool for use. Step 2, add the organic cation solution based on the first step, and the spin coater parameters are the same as the first step. After the spin coating is completed, place the sample on a heating table, anneal at 100℃ for 50 minutes, and then cool for use.

[0105] A one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate was prepared by spin coating process: 1,3-dimethylimidazolium dimethyl phosphate was dissolved in IPA to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution with a concentration of 0.5 mg / mL, and the parameters of the spin coater were set: the rotation speed was 4000 r / s, and it ran for 30 seconds. Then, the 1,3-dimethylimidazolium dimethyl phosphate solution was dropped on the surface of the three-dimensional perovskite layer and the spin coater was turned on. After the spin coating was completed, annealing was performed at 100°C for 5 minutes.

[0106] On the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate, C 60 , 8nm BCP and 90nm Ag to obtain a perovskite solar cell.

[0107] Example 4

[0108] A method for preparing a perovskite solar cell comprises the following steps:

[0109] Cleaning and UV-ozone treatment of ITO substrate: Place the ITO substrate in a beaker, ultrasonically clean it in a detergent aqueous solution for 15 minutes, then ultrasonically clean it in deionized water for 15 minutes, and finally ultrasonically clean it in isopropanol for 15 minutes. After completion, blow dry it with nitrogen.

[0110] The nickel oxide electron transport layer was prepared by spin coating: nickel oxide solution was prepared: 0.1 mol L -1 Nickel acetate was dissolved in 5 ml of ethanol, and then 0.05 ml of ethanolamine was slowly added dropwise, and then stirred for 4 h. The parameters of the spin coater were set as follows: the spin coating speed was 3000 rpm / s, and the acceleration was 1500 rpm / s. 2 , run for 30 seconds. Drop the nickel oxide solution on the surface of the cleaned ITO substrate, start the spin coater, anneal at 280℃ for 1h after the spin coating, and cool to room temperature for use.

[0111] Two-step spin coating to prepare three-dimensional perovskite layer: ① Prepare the solution of perovskite active layer: dissolve 1.5 mol of lead iodide in 1 mL of DMF solution to obtain lead iodide solution; dissolve FAI, MACl, and MABr in IPA solution, stir evenly to obtain an organic cation solution, in which the mass concentrations of FAI, MACl, and MABr are 90 mg / mL, 9 mg / mL, and 6 mg / mL, respectively. ② Preparation of perovskite active layer: Step 1, UV treat the ITO substrate with an electron transport layer on the surface for 30 minutes. Set the parameters of the spin coater: rotation speed is 1500 rpm / s, acceleration is 1500 rpm / s 2 , run for 30 seconds. Drop the lead iodide solution on the surface of the electron transport layer and turn on the spin coater. After the spin coating is completed, anneal at 70℃ for 60 seconds and then cool for use. Step 2, add the organic cation solution based on the first step, and the spin coater parameters are the same as the first step. After the spin coating is completed, place the sample on the heating table, anneal at 100℃ for 50 minutes, and then cool for use.

[0112] A one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate was prepared by spin coating process: 1,3-dimethylimidazolium dimethyl phosphate was dissolved in IPA to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution with a concentration of 0.5 mg / mL, and the parameters of the spin coater were set: the rotation speed was 4000 r / s, and it ran for 30 seconds. Then, the 1,3-dimethylimidazolium dimethyl phosphate solution was dropped on the surface of the three-dimensional perovskite layer and the spin coater was turned on. After the spin coating was completed, annealing was performed at 100°C for 5 minutes.

[0113] The PCBM hole transport layer was prepared by spin coating: PCBM solution was used for spin coating. The PCBM solution was prepared as follows: 30 mg PCBM was dissolved in 1 mL chlorobenzene. The parameters of the spin coater were set as follows: the speed was 3000 rpm / s and the acceleration was 3000 rpm / s. 2 , run for 40 seconds. Drop the PCBM solution on the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate, turn on the spin coater, and obtain a hole transport layer.

[0114] A silver electrode with a thickness of about 90 nm is evaporated on the surface of the hole transport layer to obtain a perovskite solar cell.

[0115] Control group

[0116] A method for preparing a perovskite solar cell. The comparative example method is basically the same as the method in Example 1, except that: no spin coating process is used to prepare a one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate, and a hole transport layer is directly prepared on the three-dimensional perovskite layer.

[0117] The three-dimensional perovskite layer modified with the novel one-dimensional perovskite containing imidazole ring prepared in Example 1 and the three-dimensional perovskite layer prepared in the control group were subjected to electron microscope scanning and contact angle test. Figure 2 and Figure 4 As shown; the photoelectric conversion efficiency of the perovskite solar cells prepared in Example 1 and the control group was compared, as shown Figure 3 shown.

[0118] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The following steps are involved: providing a conductive substrate; preparing an electron transport layer on the conductive substrate; Preparing a three-dimensional perovskite layer on the surface of the electron transport layer; coating a 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, and performing a first annealing treatment to obtain a one-dimensional passivation layer containing imidazole rings; Preparing a hole transport layer on the surface of the one-dimensional passivation layer containing imidazole rings; An electrode is prepared on the surface of the hole transport layer.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The step of coating a 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer and performing a first annealing treatment to obtain a one-dimensional passivation layer containing imidazole rings specifically comprises: dissolving 1,3-dimethylimidazolium dimethyl phosphate in an organic solvent to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution; The 1,3-dimethylimidazolium dimethyl phosphate solution is spin-coated on the surface of the three-dimensional perovskite layer, and a first annealing treatment is performed at a temperature of 90 to 150° C. for 1 to 10 minutes to obtain the one-dimensional passivation layer containing imidazole rings.

3. The method for preparing a perovskite solar cell according to claim 2, characterized in that: In the 1,3-dimethylimidazolium dimethyl phosphate solution, the concentration of 1,3-dimethylimidazolium dimethyl phosphate is 0.1-2 mg / mL.

4. The method for preparing a perovskite solar cell according to claim 2, characterized in that: In the step of spin coating the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, the spin coating speed is 1000 to 5000 r / s, and the spin coating time is 20 to 60 s.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The step of preparing a three-dimensional perovskite layer on the surface of the electron transport layer specifically comprises: providing a lead iodide solution and an organic cation solution; Spin coating the lead iodide solution on the surface of the electron transport layer and performing a second annealing treatment to obtain a lead iodide layer; The organic cation solution is spin-coated on the surface of the lead iodide layer, and a third annealing treatment is performed to obtain the three-dimensional perovskite layer.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In the step of spin coating the lead iodide solution on the surface of the electron transport layer, the spin coating speed is 500 to 3000 r / s and the spin coating time is 20 to 60 s; And / or; the temperature of the second annealing treatment is 50-100°C and the time is 20-100s.

7. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In the step of spin coating the organic cationic solution on the surface of the lead iodide layer, the spin coating speed is 500 to 3000 r / s and the spin coating time is 20 to 60 s; And / or; the temperature of the third annealing treatment is 80-150°C, the humidity is 10-40%, and the time is 40-80 minutes.

8. The method for preparing a perovskite solar cell according to claim 5, characterized in that: In the organic cation solution, the solute is selected from one or more of formamidine, methylamine hydroiodide, methylamine hydrochloride, and methylamine hydrobromide.

9. A perovskite solar cell, characterized in that: The method described in any one of 1-8 is used to prepare the product.

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