A perovskite solar cell and its preparation method

Abstract

The present invention discloses a perovskite solar cell and a preparation method thereof. The preparation method includes 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 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 an imidazole ring; preparing a hole transport layer on the surface of the one-dimensional passivation layer containing an imidazole ring; and preparing an electrode on the surface of the hole transport layer. By introducing 1,3-dimethylimidazolium dimethyl phosphate on the surface of the three-dimensional perovskite layer, the present invention promotes the formation of a one-dimensional perovskite containing an imidazole ring. The establishment of this method can not only improve the photovoltaic performance of the perovskite solar cell, but also have excellent long-term stability, which helps to promote the perovskite solar cell towards large-scale production and commercial application.

Description

Technical Field

[0001] The present invention relates to the technical field of solar energy preparation, and particularly relates 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, as well as advantages such as low cost, suitability for solution processing, and the ability to form large-area films. These advantages have enabled them to show broad application prospects in the optoelectronic field. Traditional three-dimensional perovskite solar cells have achieved remarkable power conversion efficiencies, reaching 25.7%.

[0003] However, long-term stability has become the main challenge faced by current three-dimensional perovskite solar cells. This is because three-dimensional perovskite materials are prone to ion migration, resulting in unstable structures. Moreover, their tolerance to ultraviolet light, oxygen, humidity, high temperature, and electric fields in the surrounding environment is relatively poor, leading to a sharp reduction in the lifespan of three-dimensional perovskite solar cells and becoming a bottleneck restricting their practical applications. Therefore, while ensuring the photovoltaic performance of perovskite solar cells, improving the long-term stability of solar cells has become the focus of research.

[0004] Therefore, the existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the deficiencies of the above-mentioned existing technologies, 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 solutions adopted by the present invention to solve the above technical problems are as follows:

[0007] In the first aspect of the present invention, a preparation method of a perovskite solar cell is provided, including the following steps:

[0008] Provide a conductive substrate;

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

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

[0011] Coat a 1,3-dimethylimidazolium dimethylphosphate solution on the surface of the three-dimensional perovskite layer, and perform a first annealing treatment to obtain a one-dimensional passivation layer containing an imidazole ring;

[0012] Prepare a hole transport layer on the surface of the one-dimensional passivation layer containing an imidazole ring;

[0013] Prepare an electrode on the surface of the hole transport layer.

[0014] Preferably, a 1,3-dimethylimidazolium dimethyl phosphate solution is coated on the surface of the three-dimensional perovskite layer, and a first annealing treatment is performed to obtain a one-dimensional passivation layer containing an imidazole ring, specifically including:

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

[0016] Spin-coat the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, and perform a first annealing treatment at a temperature of 90 - 150 °C. After 1 - 10 minutes, the one-dimensional passivation layer containing an imidazole ring is obtained.

[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 - 5000 r / s, and the spin-coating time is 20 - 60 s.

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

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

[0021] Spin-coat the lead iodide solution on the surface of the electron transport layer, and perform a second annealing treatment to obtain a lead iodide layer;

[0022] Spin-coat the organic cation solution on the surface of the lead iodide layer, and perform a third annealing treatment 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 - 3000 r / s, and the spin-coating time is 20 - 60 s;

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

[0025] Preferably, in the step of spin-coating the organic cation 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;

[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 min.

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

[0028] In a second aspect of the present invention, there is provided a perovskite solar cell prepared by the above preparation method.

[0029] Beneficial effects:

[0030] In the present invention, 1,3-dimethylimidazolium dimethyl phosphate is introduced 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 an imidazole ring can effectively passivate defects, and at the same time regulate the energy level alignment, promoting the transport and extraction of charges. Moreover, the hydrophobicity of the one-dimensional perovskite containing an imidazole ring contributes to the improvement of the stability of the mixed-dimensional perovskite of the present invention. The strong chemical interaction 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 in the present invention can not only improve the photovoltaic performance of the device, but also has excellent long-term stability, which helps to promote the perovskite photovoltaic device towards large-scale production and commercial application. Description of the drawings

[0031] Figure 1 Optical image of the one-dimensional perovskite single crystal prepared in Example 1 of the present invention;

[0032] Figure 2 Scanning electron microscope images of the three-dimensional perovskite layer modified with the one-dimensional perovskite containing an imidazole ring prepared in Example 1 of the present invention and the three-dimensional perovskite layer prepared by the control group;

[0033] Figure 3 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 chart of the three-dimensional perovskite layer modified with the one-dimensional perovskite containing an imidazole ring prepared in Example 1 of the present invention and the three-dimensional perovskite layer prepared by the control group. Detailed implementation manners

[0035] The present invention provides a perovskite solar cell and a preparation method thereof. To make the objectives, technical solutions and effects of the present invention clearer and more definite, 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 used to limit the present invention.

[0036] The excess lead iodide remaining on the surface of the three-dimensional perovskite layer results in insufficient stability of the existing three-dimensional perovskite solar cells.

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

[0038] Provide a conductive substrate;

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

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

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

[0042] Prepare a hole transport layer on the surface of the one-dimensional passivation layer containing an imidazole ring;

[0043] Prepare an electrode 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 an imidazole ring on the surface of the three-dimensional perovskite layer. 1,3-dimethylimidazolium dimethyl phosphate can combine with the residual lead iodide on the surface of the three-dimensional perovskite layer to form a one-dimensional perovskite containing an imidazole ring, reducing the residual lead iodide and thus improving the stability; moreover, the one-dimensional perovskite containing an imidazole ring has better hydrophobicity than the three-dimensional perovskite, and thus has a stronger resistance to water. Furthermore, there is a strong chemical interaction between the one-dimensional perovskite containing an imidazole ring and the three-dimensional perovskite. On the one hand, it can passivate defects, and on the other hand, it can effectively inhibit the migration of ions. Combined with the reduction of residual lead iodide, the stability of the perovskite solar cell is significantly improved in many aspects; finally, the passivation of the defects of the three-dimensional perovskite and the energy level regulation by the one-dimensional perovskite containing an imidazole ring can significantly improve the charge transport and reduce the non-radiative recombination, so that the photoelectric conversion efficiency is further improved. Combined with the enhanced stability, the perovskite solar cell prepared by the present invention has the properties of high efficiency and stability.

[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 can be, but is not limited to, one of ITO substrates, FTO substrates, etc. Further, the flexible conductive film substrate can be, but is not limited to, one of PET substrates, PEN substrates, etc.

[0046] In some embodiments, the conductive substrate is a conductive substrate that has been subjected to cleaning treatment and ultraviolet ozone treatment. Specifically, first, the conductive substrate is subjected to cleaning treatment, and then the cleaned conductive substrate is subjected to ultraviolet ozone treatment. Further, the steps of the cleaning treatment are as follows: The conductive substrate is ultrasonically cleaned successively with an aqueous solution of a cleaning agent, deionized water, and isopropyl alcohol, and then dried with nitrogen gas.

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

[0048] Prepare 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, spraying, chemical bath, etc.), and after annealing treatment, the electron transport layer is obtained.

[0050] In some embodiments, the electron transport material solution can 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 can be an inorganic electron transport material solution, such as a titanium dioxide solution or a tin dioxide solution, etc.

[0052] In some embodiments, in the 1,3-dimethylimidazolium dimethyl phosphate solution, the concentration of 1,3-dimethylimidazolium dimethyl phosphate is 0.1 to 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, 2 mg / mL.

[0053] The present invention controls the concentration of 1,3-dimethylimidazolium dimethyl phosphate within 0.1 to 2 mg / mL because within this range, an appropriate number of one-dimensional perovskites can be formed. When the concentration is less than 0.1 mg / mL, the one-dimensional perovskites are relatively small, so the improvement in performance efficiency is not obvious. When the concentration is greater than 2 mg / mL, it will cause too many perovskites, although the stability is improved, but the efficiency decreases. And between 0.1 and 2 mg / mL, both the photoelectric conversion efficiency and the 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 simultaneous improvement of the photoelectric conversion efficiency and the stability of the device is the most obvious.

[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 min, ideal perovskite crystals cannot be formed. Excessive temperature or too long time will damage the function 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 min.

[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, it specifically includes:

[0061] Preparing a hole transport material solution;

[0062] Using a solution method (such as spin-coating, blade coating, chemical bath, etc.) to coat the hole transport material solution on the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate, and after annealing treatment, obtaining the hole transport layer.

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

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

[0065] In the step of fabricating the electrode on the surface of the hole transport layer, in some embodiments, it specifically includes: a metal electrode with a thickness of 80 nm can be sprayed on the surface of the hole transport layer by using a vacuum spraying device.

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

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

[0068] Spin-coat the lead iodide solution on the surface of the electron transport layer, and perform a second annealing treatment to obtain a lead iodide layer;

[0069] Spin-coat the organic cation solution on the surface of the lead iodide layer, and perform a third annealing treatment 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 spinning speed is 500 - 3000 r / s, and the spinning time is 20 - 60 s; the spinning speed can be 500 r / s, 1000 r / s, 1500 r / s, 2000 r / s, 2500 r / s, 3000 r / s, and the spinning 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 - 100 s. 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 20 s, 30 s, 40 s, 50 s, 60 s.

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

[0073] In some embodiments, the solvent of the lead iodide solution can be, but is not limited to, one or more of dimethyl sulfoxide, N,N-dimethylformamide, γ-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 spinning speed is 1500 r / s, and the spinning time is 30 s;

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

[0076] In some embodiments, in the step of spin-coating the organic cation solution on the surface of the lead iodide layer, the rotation speed of spin-coating is 500 - 3000 r / s, and the time of spin-coating is 20 - 60 s; the rotation speed of spin-coating 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 time of spin-coating 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 40 min, 50 min, 60 min, 70 min, 80 min.

[0078] In the present invention, the temperature of the third annealing treatment is 80 - 150 °C, because when the temperature is relatively high, it will cause the degradation of perovskite at high temperature, and when the temperature is relatively low, it is not conducive to the crystallization of perovskite; the present invention also anneals in a closed environment with different humidities, and sets the humidity to 10 - 40%, and the 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 rotation speed of spin-coating is 1700 r / s, and the time of spin-coating 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 min.

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

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

[0083] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments, and are only used to illustrate the present invention and in no way limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0084] Example 1

[0085] A preparation method of a perovskite solar cell, comprising the following steps:

[0086] Cleaning and ultraviolet ozone treatment of the ITO substrate: Place the ITO substrate in a beaker, ultrasonically clean it in an aqueous cleaning agent solution for 15 min, then ultrasonically clean it in deionized water for 15 min, and finally ultrasonically clean it in isopropanol for 15 min. After completion, dry it with nitrogen gas. Place the cleaned ITO substrate in a UV instrument and perform ozone treatment for 30 min.

[0087] Prepare a tin dioxide electron transport layer (50 nm) by spin coating: Configure a tin dioxide solution (dilute the tin dioxide solution with deionized water, and 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, and the acceleration is 4000 rpm / s 2 , and run for 30 s. Drop the tin dioxide solution on the surface of the ITO substrate after UV treatment, start the spin coater, and after spin coating, anneal the sample on a heating table at 150 °C for 30 min.

[0088] Prepare a three-dimensional perovskite layer (700 nm) by a two-step method: ① Configure a solution of 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 IPA solution and stir evenly to obtain an organic cation solution, where 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: First step, perform UV treatment on the ITO substrate with an electron transport layer on its surface for 30 min. Set the parameters of the spin coater: the rotation speed is 1500 rpm / s, and the acceleration is 1500 rpm / s 2 , and run for 30 s. Drop the lead iodide solution on the surface of the electron transport layer and start the spin coater. After spin coating, anneal at 70 °C for 60 s and then cool for standby. Second step, on the basis of the first step, drop the organic cation solution, and the parameters of the spin coater are the same as those in the first step. After spin coating, place the sample on a heating table, anneal at 100 °C for 50 min and then cool for standby.

[0089] Prepare a one-dimensional passivation layer (80 nm) containing an imidazole ring by spin coating: Dissolve 1,3-dimethylimidazolium dimethyl phosphate in IPA to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution with a concentration of 0.5 mg / mL. Set the parameters of the spin coater: the rotation speed is 4000 r / s, run for 30 s, then drop the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer and start the spin coater. After spin coating, anneal at 100 °C for 5 min.

[0090] Preparation of spiro-OMeTAD hole transport layer (200 nm) by spin coating method: Spin coat with spiro-OMeTAD solution, and the preparation of spiro-OMeTAD solution is as follows: Mix 72.5 mg of spiro-OMeTAD, 36 μL of TBP, and 30 μL of LiTFSI solution (the solvent is acetonitrile, 260 mg of LiTFSI, 1 mL of acetonitrile) in 1 mL of chlorobenzene. Set the parameters of the spin coater: the rotation speed is 4000 rpm / s, and the acceleration is 4000 rpm / s 2 , and run for 30 s. 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 let it stand in the dark for 12 hours after spin coating to obtain the hole transport layer.

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

[0092] Example 2

[0093] A preparation method of a perovskite solar cell, comprising the following steps:

[0094] Cleaning and ultraviolet ozone treatment of the FTO substrate: Place the FTO substrate in a beaker, ultrasonically clean it in deionized water and cleaning agent solution for 30 min, then ultrasonically clean it in deionized water for 30 min, and finally ultrasonically clean it in isopropanol for 30 min. After completion, dry it with nitrogen. Place the cleaned FTO substrate in a UV instrument and perform ozone treatment for 30 min.

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

[0096] Preparation of three-dimensional perovskite layer by two-step spin coating: ① Preparation of the solution of 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 IPA solution and stir evenly to obtain an organic cation solution, where 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: First step, perform UV treatment on the FTO substrate with an electron transport layer on its surface for 30 min. Set the parameters of the spin coater: the rotation speed is 1500 rpm / s, and the acceleration is 1500 rpm / s 2 , and run for 30 s. Drop the lead iodide solution on the surface of the electron transport layer and turn on the spin coater. After spin coating is completed, anneal at 70 °C for 60 s and then cool for standby. Second step, based on the first step, drop the organic cation solution, and the parameters of the spin coater are the same as those in the first step. After spin coating is completed, place the sample on a heating stage, anneal at 100 °C for 50 min and then cool for standby.

[0097] Preparation of a one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate by spin coating process: Dissolve 1,3-dimethylimidazolium dimethyl phosphate in IPA to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution with a concentration of 1 mg / mL. Set the parameters of the spin coater: the rotation speed is 4000 r / s, run for 30 s, then drop the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer and turn on the spin coater. After spin coating is completed, anneal at 100 °C for 5 min.

[0098] Preparation of spiro-OMeTAD hole transport layer by spin coating method: Spin coat with spiro-OMeTAD solution. The preparation of the spiro-OMeTAD solution is as follows: Mix 72.5 mg of spiro-OMeTAD, 36 μL of TBP, and 30 μL of LiTFSI solution (the solvent is acetonitrile, 260 mg of LiTFSI, 1 mL of acetonitrile) in 1 mL of chlorobenzene. Set the parameters of the spin coater: the rotation speed is 4000 rpm / s, and the acceleration is 4000 rpm / s 2 , and run for 30 s. 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, let it stand in the dark overnight for oxidation to obtain the hole transport layer.

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

[0100] Example 3

[0101] A preparation method of a perovskite solar cell, comprising the following steps:

[0102] Cleaning and ultraviolet ozone treatment of ITO substrate: Place the ITO substrate in a beaker, ultrasonically clean it in an aqueous cleaning agent solution for 15 min, then ultrasonically clean it in deionized water for 15 min, and finally ultrasonically clean it in isopropyl alcohol for 15 min. After completion, dry it with nitrogen gas.

[0103] Preparation of PEDOT:PSS hole transport layer by spin coating: Spin coat with PEDOT:PSS solution. The preparation of PEDOT:PSS solution is as follows: Mix PEDOT:PSS and ethanol evenly according to a volume ratio of 1:3 and filter it with a 45 nm filter head. Set the parameters of the spin coater: rotation speed is 4000 rpm / s, acceleration is 2000 rpm / s2, and run for 60 s. Drop the filtered PEDOT:PSS solution on the ITO substrate, turn on the spin coater, and anneal at 150 °C for 0.5 h after spin coating. Cool it and set aside for later 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 and stir evenly to obtain organic cation solution, where 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: First step, perform UV treatment on the ITO substrate with a hole transport layer on its surface for 30 min. Set the parameters of the spin coater: rotation speed is 1500 rpm / s, acceleration is 1500 rpm / s 2 , and run for 30 s. Drop the lead iodide solution on the surface of the hole transport layer and turn on the spin coater. After spin coating, anneal at 70 °C for 60 s and then cool it for later use. Second step, on the basis of the first step, drop the organic cation solution. The parameters of the spin coater are the same as those in the first step. After spin coating, place the sample on a heating stage and anneal at 100 °C for 50 min and then cool it for later use.

[0105] Prepare a one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate by spin coating process: Dissolve 1,3-dimethylimidazolium dimethyl phosphate in IPA to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution with a concentration of 0.5 mg / mL. Set the parameters of the spin coater: rotation speed is 4000 r / s, run for 30 s, then drop the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer and turn on the spin coater. After spin coating, anneal at 100 °C for 5 min.

[0106] Evaporate a 28 nm thick C 60 、8 nm thick BCP and 90 nm thick Ag successively on the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate to obtain a perovskite solar cell.

[0107] Example 4

[0108] A preparation method of a perovskite solar cell, comprising the following steps:

[0109] Cleaning and ultraviolet ozone treatment of the ITO substrate: Place the ITO substrate in a beaker, ultrasonically clean it in an aqueous cleaning agent solution for 15 min, then ultrasonically clean it in deionized water for 15 min, and finally ultrasonically clean it in isopropanol for 15 min. After completion, dry it with nitrogen.

[0110] Preparing a nickel oxide electron transport layer by a spin coating process: Prepare a nickel oxide solution: Dissolve 0.1 Mol L -1 nickel acetate in 5 ml of ethanol, then slowly add 0.05 mL of ethanolamine dropwise, and then stir for 4 h. Set the parameters of the spin coater: the spin coating speed is 3000 rpm / s, and the acceleration is 1500 rpm / s 2 , and run for 30 s. Drop the nickel oxide solution on the surface of the cleaned ITO substrate, start the spin coater, and anneal at 280 °C for 1 h after spin coating. After cooling to room temperature, set aside.

[0111] Preparing a three-dimensional perovskite layer by a two-step spin coating method: ① Prepare a solution of 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 IPA solution and stir evenly to obtain an organic cation solution, wherein the mass concentrations of FAI, MACl, and MABr are 90 mg / mL, 9 mg / mL, and 6 mg / mL respectively. ② Preparation of the perovskite active layer: First step, perform UV treatment on the ITO substrate with an electron transport layer on its surface for 30 min. Set the parameters of the spin coater: the rotation speed is 1500 rpm / s, and the acceleration is 1500 rpm / s 2 , and run for 30 s. Drop the lead iodide solution on the surface of the electron transport layer and start the spin coater. After spin coating, anneal at 70 °C for 60 s and then cool for standby. Second step, based on the first step, drop the organic cation solution, and the parameters of the spin coater are the same as those in the first step. After spin coating, place the sample on a heating stage, anneal at 100 °C for 50 min and then cool for standby.

[0112] Preparing a one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate by a spin coating process: Dissolve 1,3-dimethylimidazolium dimethyl phosphate in IPA to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution with a concentration of 0.5 mg / mL. Set the parameters of the spin coater: the rotation speed is 4000 r / s, run for 30 s, then drop the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer and start the spin coater. After spin coating, anneal at 100 °C for 5 min.

[0113] The PCBM hole transport layer was prepared by spin coating: PCBM solution was spin coated, and the preparation of the PCBM solution was as follows: 30 mg of PCBM was dissolved in 1 mL of chlorobenzene. The parameters of the spin coater were set: the rotation speed was 3000 rpm / s, and the acceleration was 3000 rpm / s 2 , and it ran for 40 s. The PCBM solution was dropped on the surface of the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate, and the spin coater was turned on to obtain the hole transport layer.

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

[0115] Control group

[0116] A preparation method of a perovskite solar cell. The method of this comparative example is basically the same as that of Example 1, except that: the step of preparing the one-dimensional passivation layer containing 1,3-dimethylimidazolium dimethyl phosphate by spin coating process was not adopted, and the hole transport layer was directly prepared on the three-dimensional perovskite layer.

[0117] The three-dimensional perovskite layer modified by 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 microscopy scanning and contact angle measurement, as Figure 2 and Figure 4 shown; The photoelectric conversion efficiencies of the perovskite solar cells prepared in Example 1 and the control group were compared, as Figure 3 shown.

[0118] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A preparation method of a perovskite solar cell, characterized in that It includes the following steps: Provide a conductive substrate; Prepare an electron transport layer on the conductive substrate; Prepare a three-dimensional perovskite layer on the surface of the electron transport layer; Coat a 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, and perform a first annealing treatment to obtain a one-dimensional passivation layer containing an imidazole ring; Prepare a hole transport layer on the surface of the one-dimensional passivation layer containing an imidazole ring; Prepare an electrode on the surface of the hole transport layer.

2. The preparation method of the perovskite solar cell according to claim 1, wherein 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 an imidazole ring specifically includes: Dissolve 1,3-dimethylimidazolium dimethyl phosphate in an organic solvent to obtain a 1,3-dimethylimidazolium dimethyl phosphate solution; Spin-coat the 1,3-dimethylimidazolium dimethyl phosphate solution on the surface of the three-dimensional perovskite layer, and perform a first annealing treatment at a temperature of 90-150 °C. After 1-10 min, obtain the one-dimensional passivation layer containing an imidazole ring.

3. The preparation method of the perovskite solar cell according to claim 2, wherein, In the 1,3-dimethylimidazolium dimethyl phosphate solution, the concentration of 1,3-dimethylimidazolium dimethyl phosphate is 0.1-2 mg / mL.

4. The preparation method of the perovskite solar cell according to claim 2, wherein 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.

5. The preparation method of the perovskite solar cell according to claim 1, wherein, The step of preparing a three-dimensional perovskite layer on the surface of the electron transport layer specifically includes: Provide a lead iodide solution and an organic cation solution; Spin-coat the lead iodide solution on the surface of the electron transport layer, and perform a second annealing treatment to obtain a lead iodide layer; Spin-coat the organic cation solution on the surface of the lead iodide layer, and perform a third annealing treatment to obtain the three-dimensional perovskite layer.

6. The preparation method of the 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 500-3000 r / s, and the spin-coating time is 20-60 s; and / or; the temperature of the second annealing treatment is 50-100 °C, and the time is 20-100 s.

7. The preparation method of the perovskite solar cell according to claim 5, wherein In the step of spin-coating the organic cation 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; 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.

8. The preparation method of the perovskite solar cell according to claim 5, wherein In the organic cation solution, the solute is selected from one or more of formamidine, methylammonium hydroiodide, methylammonium hydrochloride, and methylammonium hydrobromide.

9. A perovskite solar cell, characterized in that, Prepared by the method according to any one of claims 1-8.

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