Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof, and belongs to the technical field of perovskite photovoltaics. The method comprises the following steps: sequentially forming an A-site cationic compound layer, an inorganic skeleton and a perovskite precursor solution layer on the surface of a hole transport layer; and performing high-temperature and humidity annealing on the laminated structure, so that the A-site cationic compound permeating into the inorganic skeleton reacts with PbI2 in the inorganic skeleton to generate a perovskite material, and the perovskite precursor solution permeating into the inorganic skeleton reacts with PbI2 to generate a perovskite material, thereby obtaining the perovskite light absorption layer. In the preparation process of the perovskite light absorption layer, the A-site cationic compound layer is formed on the surface of the hole transport layer in advance, so that the crystallinity of an inorganic skeleton can be improved, and PbI2 is prevented from remaining on one surface, facing the electron transport layer, of the inorganic skeleton; the problem of low photoelectric conversion efficiency of the perovskite solar cell due to the fact that part of inorganic frameworks cannot be converted into perovskite materials in the prior art is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite photovoltaic technology, and particularly relates to a perovskite solar cell and a preparation method thereof. Background Art

[0002] Perovskite solar cells are the third-generation new photovoltaic materials, which have the characteristics of simple preparation process, large spectral absorption range, low cost, etc. The perovskite light-absorbing layer in perovskite solar cells is one of the key film layers.

[0003] In the prior art, the preparation of the perovskite light-absorbing layer usually adopts a two-step method, that is, evaporating lead iodide and cesium bromide to form an inorganic framework, and spin-coating methylammonium bromide (MABr), methylammonium chloride (MACl) and formamidinium iodide (FAI) on the inorganic framework, followed by annealing at high temperature and humidity to form a perovskite light-absorbing layer.

[0004] Due to the relatively thick and highly dense inorganic framework, in the initial stage of the spin-coating process, a denser perovskite layer will be formed first on the surface layer of methylammonium bromide (MABr), methylammonium chloride (MACl), formamidinium iodide (FAI) and the inorganic framework. The perovskite layer will hinder the penetration of subsequent methylammonium bromide (MABr) and formamidinium iodide (FAI), resulting in that part of the inorganic framework cannot be converted into perovskite material, and thus the photoelectric conversion efficiency of the perovskite solar cell is low. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a perovskite solar cell and a preparation method thereof, which solve the problem that the photoelectric conversion efficiency of the perovskite solar cell is low due to the fact that part of the inorganic framework cannot be converted into perovskite material in the prior art.

[0006] The object of the present invention is mainly achieved through the following technical solutions:

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

[0008] Step 1: Provide a conductive substrate;

[0009] Step 2: Form a hole transport layer on the surface of the conductive substrate;

[0010] Step 3: Sequentially form an A-site cation compound layer, an inorganic framework and a perovskite precursor solution layer on the surface of the hole transport layer to obtain a stacked structure;

[0011] Perform high-temperature and humidity annealing on the stacked structure, so that the A-site cation compound penetrating into the inorganic framework reacts with PbI2 in the inorganic framework to generate perovskite material, and the perovskite precursor solution penetrating into the inorganic framework reacts with PbI2 to generate perovskite material, thereby obtaining a perovskite light-absorbing layer;

[0012] Step 4: An electron transport layer and a positive electrode are sequentially formed on the surface of the perovskite light-absorbing layer to obtain a perovskite solar cell; or, an electron transport layer, a buffer layer, a front recombination layer, and a positive electrode are sequentially formed on the surface of the perovskite light-absorbing layer, an antireflection layer is formed on the surface of the front recombination layer between the two positive electrodes, and a back electrode is formed on the back of the conductive substrate to obtain a perovskite solar cell.

[0013] Further, the A-site cation compound is one or more of methyl iodide, methyl bromide, methyl chloride, methylammonium iodide, methylammonium bromide, methylammonium chloride, butylammonium iodide, butylammonium bromide, and butylammonium chloride in any proportion.

[0014] Further, the thickness ratio of the A-site cation compound layer, the inorganic framework, and the perovskite light-absorbing layer is 6-11: 200-320: 350-550.

[0015] Further, Step 3 includes the following steps:

[0016] Step 31: Evaporate the A-site cation compound on the surface of the hole transport layer to form an A-site cation compound layer;

[0017] Step 32: Evaporate cesium bromide and lead iodide on the surface of the A-site cation compound layer to form an inorganic framework;

[0018] Step 33: Spin-coat the perovskite precursor solution on the surface of the inorganic framework to form a perovskite precursor solution layer, and correspondingly form a stacked structure on the surface of the hole transport layer;

[0019] Step 34: Perform high-temperature and humidity annealing on the stacked structure, so that the A-site cation compound penetrating into the inorganic framework reacts with PbI2 in the inorganic framework to generate perovskite material, and the perovskite precursor solution penetrating into the inorganic framework reacts with PbI2 to generate perovskite material, obtaining a perovskite light-absorbing layer.

[0020] Further, in Step 31, the evaporation rate of the A-site cation compound is The vacuum degree is 1.5-1.8×10 -3 Pa.

[0021] Further, in Step 32, the evaporation rate of cesium bromide in the inorganic framework is The evaporation rate of lead iodide is The vacuum degree is 9.5-10.5×10 -4 Pa.

[0022] Further, the composition of the perovskite precursor solution includes methyl iodide, methylammonium chloride, methylammonium bromide, and an organic solvent.

[0023] Further, the mass ratio of iodoanisole, methylammonium chloride, and methylammonium bromide in the perovskite precursor solution is 75-80:5.5-6.0:12-13.

[0024] Further, in step 33, the stirring temperature is 20-30 °C, and the stirring time is 25-35 min.

[0025] Further, in step 34, the high-temperature and high-humidity annealing temperature is 150-170 °C, the high-temperature and high-humidity annealing humidity is 50-75%, and the high-temperature and high-humidity annealing time is 20-30 min.

[0026] In a second aspect, the present invention also provides a perovskite solar cell prepared by using the preparation method of the above perovskite solar cell.

[0027] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0028] A) In the preparation method of the perovskite solar cell provided by the present invention, during the preparation of the perovskite light-absorbing layer, a layer of A-site cation compound layer is pre-formed on the surface of the hole transport layer. The A-site cation compound layer can serve as the seed crystal for crystal growth during the formation of the inorganic framework, improve the crystallinity of the inorganic framework, make the internal structure of the inorganic framework more uniform, and thus improve the photoelectric conversion efficiency of the obtained perovskite solar cell.

[0029] B) In the preparation method of the perovskite solar cell provided by the present invention, during the preparation of the perovskite light-absorbing layer, a layer of A-site cation compound layer is pre-formed on the surface of the hole transport layer. During the subsequent high-temperature and high-humidity annealing process, the A-site cation compound and the perovskite precursor solution can penetrate and diffuse from two directions, the light-receiving surface and the backlight surface of the inorganic framework, respectively generating perovskite materials, thereby avoiding the residue of PbI2 on the side of the inorganic framework facing the electron transport layer, ensuring the uniformity of the perovskite light-absorbing layer, obtaining a high-quality and uniform-textured perovskite light-absorbing layer, and further improving the energy conversion efficiency of the perovskite solar cell.

[0030] Other features and advantages of the present invention will be described in the subsequent specification, and some will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the written specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings are only for the purpose of showing specific embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference signs represent the same components.

[0032] Figure 1Schematic structural diagram of the perovskite single-junction solar cell provided by the present invention;

[0033] Figure 2 Schematic structural diagram of the perovskite tandem solar cell provided by the present invention;

[0034] Figure 3 XRD spectrum comparison diagram of the perovskite light-absorbing layer with pre-embedded FAI and the reference perovskite thin film in Example 1.

[0035] Reference numerals:

[0036] 1 - Conductive substrate; 2 - Hole transport layer; 3 - Perovskite light-absorbing layer; 4 - Electron transport layer; 5 - Buffer layer; 6 - Front surface recombination layer; 7 - Positive electrode; 8 - Back electrode; 9 - Antireflection layer. Specific embodiments

[0037] The following specifically describes the preferred embodiments of the present invention in conjunction with the accompanying drawings, wherein the accompanying drawings form a part of the present invention and are used together with Embodiment 1 of the present invention to illustrate the principle of the present invention.

[0038] In the first aspect of the present invention, a method for preparing a perovskite solar cell is provided, including the following steps:

[0039] Step 1: Provide a conductive substrate 1;

[0040] Step 2: Form a hole transport layer 2 on the surface of the conductive substrate 1;

[0041] Step 3: Sequentially form an A-site cation compound layer, an inorganic framework, and a perovskite precursor solution layer on the surface of the hole transport layer 2 to obtain a stacked structure. Perform high-temperature and humidity annealing on the stacked structure so that the A-site cation compound penetrating into the inorganic framework reacts with PbI2 in the inorganic framework to generate a perovskite material, and the perovskite precursor solution penetrating into the inorganic framework reacts with PbI2 to generate a perovskite material, obtaining a perovskite light-absorbing layer 3;

[0042] Step 4: Sequentially form an electron transport layer 4 and a positive electrode 7 (for example, an Ag electrode) on the surface of the perovskite light-absorbing layer 3 to obtain a perovskite solar cell.

[0043] It should be noted that the above conductive substrate 1 is a conductive glass substrate or a conductive silicon substrate.

[0044] It should also be noted that based on the chemical formula of perovskite being ABX3, the A-site cation refers to the cation in the A-site.

[0045] Correspondingly, when the conductive substrate 1 is a conductive glass substrate, the perovskite solar cell is a perovskite single-junction cell. For the structure of the perovskite single-junction cell, see Figure 1, including a conductive glass substrate and a hole transport layer 2, a perovskite light-absorbing layer 3, an electron transport layer 4, and a positive electrode 7 that are sequentially stacked on the light-receiving surface of the conductive glass substrate.

[0046] When the conductive substrate 1 is a conductive silicon substrate, the perovskite solar cell is a perovskite-silicon tandem cell. For the structure of the perovskite-silicon tandem cell, see Figure 2 , including a conductive silicon substrate, a hole transport layer 2, a perovskite light-absorbing layer 3, an electron transport layer 4, a buffer layer 5, a front recombination layer 6, and a positive electrode 7 that are sequentially stacked on the light-receiving surface of the conductive silicon substrate, an antireflection layer 9 provided on the surface of the front recombination layer 6 and located between two positive electrodes 7, and a back electrode 8 formed on the backlight surface of the conductive silicon substrate.

[0047] Based on the above structure, correspondingly, in step 4 above, after forming the electron transport layer 4 and before forming the positive electrode 7, the following steps are further included:

[0048] A buffer layer 5 (for example, a SnO2 layer) and a front recombination layer 6 (for example, an ITO layer or an IZO layer) are sequentially formed on the surface of the electron transport layer 4.

[0049] After forming the electron transport layer 4, the following steps are further included:

[0050] A back electrode 8 is formed on the back surface of the conductive substrate 1.

[0051] After forming the positive electrode 7, the following steps are further included:

[0052] An antireflection layer 9 (for example, lithium fluoride, LiF) is formed on the surface of the front recombination layer 6 between two positive electrodes 7.

[0053] Compared with the prior art, in the method for preparing a perovskite solar cell provided by the present invention, during the preparation of the perovskite light-absorbing layer 3, a layer of A-site cation compound layer is pre-formed on the surface of the hole transport layer 2. On the one hand, the A-site cation compound layer can serve as a seed for crystal growth during the formation of the inorganic framework, improving the crystallinity of the inorganic framework and making the internal structure of the inorganic framework more uniform, thereby improving the photoelectric conversion efficiency of the obtained perovskite solar cell; on the other hand, during the subsequent high-temperature and humidity annealing process, the A-site cation compound and the perovskite precursor solution can penetrate and diffuse from both the light-receiving surface and the backlight surface of the inorganic framework to generate perovskite materials respectively, thereby avoiding the residue of PbI2 on the side of the inorganic framework facing the electron transport layer 4, ensuring the uniformity of the perovskite light-absorbing layer 3, obtaining a high-quality and uniform perovskite light-absorbing layer 3, and further improving the energy conversion efficiency of the perovskite solar cell.

[0054] Exemplarily, the above A-site cation compound is one or more of formamidinium iodide (FAI), formamidinium bromide (FABr), formamidinium chloride (FACl), methylammonium iodide (MAI), methylammonium bromide (MABr), methylammonium chloride (MACl), butylammonium iodide (BAI), butylammonium bromide (BABr), and butylammonium chloride (BACl) mixed in any proportion.

[0055] In order to fully consume PbI2 to form the perovskite material, exemplarily, the thickness ratio of the above A-site cation compound layer, inorganic framework, and perovskite light-absorbing layer 3 is 6-11:200-320:350-550.

[0056] Specifically, the formation methods of the above layers are as follows:

[0057] In the above step 2, for the formation method of the hole transport layer 2, it includes the following steps:

[0058] Place the conductive substrate 1 in the mask plate of the hole transport layer 2;

[0059] Sputter a nickel oxide layer on the surface of the conductive substrate 1 in a radio frequency magnetron sputtering mode, where the vacuum degree is 9.5-10.5×10 -4 Pa, the sputtering power is 85-90 W, the argon gas flow rate is 18-25 sccm, and the sputtering time is 8-15 min;

[0060] Spin-coat a (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz) layer on the surface of the nickel oxide layer, where the dosage of 2PACz is 50-110 μL, the spin-coating speed is 2800-3000 rpm, the spin-coating acceleration is 2800-3000 rpm / s, and the spin-coating time is 25-30 s;

[0061] Place the conductive substrate 1 spin-coated with the 2PACz layer on a hot stage and anneal it at 95-100 °C for 8-10 min to form the hole transport layer 2.

[0062] In the above step 3, for the formation method of the perovskite light-absorbing layer 3, it includes the following steps:

[0063] Step 31: Place the laminated structure composed of the conductive substrate 1 and the hole transport layer 2 in the mask plate of the perovskite light-absorbing layer 3, and evaporate the A-site cation compound on the surface of the hole transport layer 2 to form an A-site cation compound layer, where the evaporation rate of the A-site cation compound is The vacuum degree is 1.5-1.8×10 -3 Pa;

[0064] Step 32: Evaporate cesium bromide and lead iodide on the surface of the A-site cation compound layer to form an inorganic framework, and the evaporation rate of cesium bromide in the inorganic framework is The evaporation rate of lead iodide is The vacuum degree is 9.5 - 10.5×10 -4 Pa;

[0065] Step 33: Spin - coat the perovskite precursor solution on the surface of the inorganic framework to form a perovskite precursor solution layer, and correspondingly form a stacked structure on the surface of the hole - transporting layer 2. Among them, the composition of the perovskite precursor solution includes formamidinium iodide (FAI), methylammonium chloride (MACl), methylammonium bromide (MABr) and an organic solvent (for example, absolute ethanol). Among them, the mass ratio of formamidinium iodide, methylammonium chloride and methylammonium bromide is 75 - 80:5.5 - 6.0:12 - 13. The spin - coating speed is 3000 - 4000 rpm, the spin - coating acceleration is 3000 - 4000 rpm / s, and the spin - coating time is 25 - 30 s;

[0066] Step 34: Transfer the stacked structure to a hot stage for high - temperature and high - humidity annealing, so that the A - site cation compound penetrating into the inorganic framework reacts with PbI₂ in the inorganic framework to generate perovskite material, and the perovskite precursor solution penetrating into the inorganic framework reacts with PbI₂ to generate perovskite material, obtaining a perovskite light - absorbing layer. Among them, the high - temperature and high - humidity annealing temperature is 150 - 170 °C, the high - temperature and high - humidity annealing humidity is 50 - 75%, and the high - temperature and high - humidity annealing time is 20 - 30 min (for example, 30 min).

[0067] In the above step 4, for the formation method of the electron - transporting layer 4, it includes the following steps:

[0068] Place the stacked structure obtained in step 3 in the mask plate of the electron - transporting layer 4, and sequentially deposit a lithium fluoride layer (LiF layer), a graphene layer (C60 layer) and a 2,9 - dimethyl - 4,7 - diphenyl - 1,10 - phenanthroline layer (BCP layer) on the surface of the perovskite light - absorbing layer 3. The deposition rate is The vacuum degree is 9.5 - 10.5×10 -4 Pa, the thickness of the lithium fluoride layer is 0.8 - 1.2 nm, the thickness of the graphene layer is 8 - 12 nm, and the thickness of the 2,9 - dimethyl - 4,7 - diphenyl - 1,10 - phenanthroline layer is 1.2 - 1.6 nm.

[0069] For the formation method of the buffer layer 5, it includes the following steps:

[0070] Deposit the buffer layer 5 on the surface of the electron - transporting layer 4. Among them, the vacuum degree is 18 - 25 Pa, the deposition temperature is 145 - 155 °C, the pressure of the water source is 45 - 55 Pa, the pressure of the tin source is 20 - 30 Pa, and the number of cycles is 180 - 220 times.

[0071] For the formation method of the front - side composite layer 6, it includes the following steps:

[0072] Place the laminated structure with the buffer layer 5 in the mask of the composite layer, and sputter (e.g., DC magnetron sputtering) the front composite layer 6 on the surface of the buffer layer 5. The substrate temperature during sputtering is 58 - 63 °C (e.g., 60 °C), and the chamber pressure during sputtering is 9.8 - 10.0×10 -4 Pa (e.g., 9.9×10 -4 Pa). The argon flow rate is 18 - 20 sccm, and the oxygen flow rate is 0.25 - 0.5 sccm (e.g., 0.3 sccm). The sputtering is divided into two times (including the first sputtering and the second sputtering carried out in sequence). The intensity of the first sputtering is 35 - 40 W, the sputtering time is 5 - 7 min (e.g., 6.5 min), the intensity of the second sputtering is 140 - 155 W (e.g., 150 W), and the sputtering time is 3.5 - 5 min (e.g., 4 min).

[0073] For the formation method of the perovskite silicon tandem cell, for the positive electrode 7 and the back electrode 8, the following steps are included:

[0074] Place the laminated structure with the front composite layer 6 in the masks of the positive electrode 7 and the back electrode 8 respectively, and then place the masks in a vacuum deposition device to prepare the positive electrode 7 and the back electrode 8. Among them, the vacuum degree is 6 - 7×10 -4 Pa, the thickness of the positive electrode 7 is 385 - 400 nm, and the thickness of the back electrode 8 is 185 - 200 nm.

[0075] For the formation method of the antireflection layer 9, the following steps are included:

[0076] Place the laminated structure with the positive electrode 7 and the back electrode 8 on the mask, and then place the mask in a vacuum deposition device to prepare the antireflection layer 9. The vacuum degree is 9.9 - 10.3×10 -4 Pa, and the thickness is 100 - 105 nm.

[0077] In the second aspect of the present invention, a perovskite solar cell is also provided, which is prepared by using the preparation method of the perovskite solar cell provided in the first aspect.

[0078] Compared with the prior art, the beneficial effects of the perovskite solar cell provided by the present invention are basically the same as those of the preparation method of the perovskite solar cell provided in the first aspect, and will not be elaborated here one by one.

[0079] Example 1

[0080] The perovskite solar cell in this example is a perovskite single - junction cell, and the conductive substrate uses a conductive glass substrate. The preparation method includes the following steps:

[0081] Step a: Place an ITO conductive glass substrate of 1.5×1.5 cm 2 in acetone and absolute ethanol in turn and ultrasonically clean for 15 min. Subsequently, after drying the ITO conductive glass substrate with nitrogen, place it in ozone for treatment for 15 min;

[0082] Step b: Place the ITO conductive glass substrate obtained in step a in a mask for sputtering the nickel oxide hole transport layer, and place the mask equipped with the ITO conductive glass substrate in a magnetron sputtering device. When the vacuum is pumped to 9.9×10 -4 Pa, select the radio frequency magnetron sputtering mode, adjust the power to 90 W, set the argon gas flow rate to 20 sccm, and the sputtering time to 10 min;

[0083] Step c: After sputtering, transfer the ITO conductive glass substrate to a spin coater in a nitrogen glove box, spin coat the 2PACz layer, where the amount of 2PACz is 50 μL, the rotation speed is 3000 rpm, the acceleration is 3000 rpm / s, and the time is 30 s. Then, anneal on a hot stage at 100 °C for 10 min to obtain a stacked structure of ITO conductive glass substrate / hole transport layer;

[0084] Step d: Place the stacked structure obtained in step c in a mask for evaporating PbI2, and place the mask in a vacuum evaporation device for FAI deposition. The evaporation rate of FAI is The vacuum degree is 1.8×10 -3 Pa, and the total evaporation thickness is 6 nm. After evaporation, a stacked structure of ITO conductive glass substrate / hole transport layer / FAI is obtained;

[0085] Step e: Place the stacked structure and the mask of step d in a vacuum evaporation device. When the vacuum is pumped to 9.9×10 - 4 Pa, adjust the rate of CsBr to The rate of PbI2 is The total evaporation thickness is 200 nm. After evaporation, a stacked structure of ITO conductive glass substrate / hole transport layer / FAI / PbI2 is obtained;

[0086] Step f: Weigh 77.5 mg of FAI, 5.7 mg of MACl, and 12.6 mg of MABr and dissolve them in 1 mL of absolute ethanol, and shake at room temperature for 30 min to obtain a perovskite precursor solution;

[0087] Place the stacked structure obtained in step e on a spin coater, drop 75 μL of perovskite precursor solution for spin coating, where the rotation speed is 3000 rpm, the acceleration is 3000 rpm / s, and the time is 30 s, to obtain a stacked structure of ITO conductive glass substrate / hole transport layer / FAI / PbI2 / perovskite precursor solution layer;

[0088] Step g: Place the stacked structure obtained in step f on a hot plate with an environmental humidity of 50% and a temperature of 150 °C for annealing for 30 min to obtain a stacked structure of ITO conductive glass substrate / hole transport layer / perovskite light-absorbing layer, where the thickness of the perovskite light-absorbing layer is 350 nm.

[0089] Step h: Place the stacked structure obtained in step g in a mask template of the electron transport layer, and place the mask template in a vacuum deposition device. When the vacuum degree is 9.9×10 -4 Pa, evaporate LiF, C60, and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The deposition rate is with thicknesses of 1 nm, 10 nm, and 1.5 nm respectively to obtain a stacked structure of ITO conductive glass substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer;

[0090] Step i: Place the stacked structure obtained in step h in a mask template for silver evaporation, and then place the mask template in a vacuum deposition device. When the vacuum degree is 9.9×10 -4 Pa, evaporate the silver electrode. The deposition rate is about, and the deposition thickness is 120 nm to obtain a perovskite single-junction cell.

[0091] Example 2

[0092] The perovskite solar cell in this example is a perovskite-silicon tandem cell, and the conductive substrate uses a conductive silicon substrate. The preparation method includes the following steps:

[0093] Step a: Cut a 15×15 cm 2 silicon bottom cell into 2×2 cm 2 silicon wafers. The center of the silicon wafer has a 1.2×1.2 cm 2 substrate composite layer. Control the cutting accuracy error within 1 mm. Anneal the cut silicon wafers at 200 °C for 15 min to obtain a conductive silicon substrate, where the thickness of the conductive silicon substrate is 150 μm;

[0094] Step b: Place the conductive silicon substrate obtained in step a in a mask template for sputtering the nickel oxide hole transport layer. Place the mask template with the conductive silicon substrate in a magnetron sputtering device, evacuate to 9.9×10 -4When the pressure is Pa, select the radio frequency magnetron sputtering mode, adjust the power to 90 W, set the argon gas flow rate to 20 sccm, and the sputtering time is 10 min;

[0095] Step c: After sputtering, transfer the conductive silicon substrate to a spin coater in a nitrogen glove box, and spin coat the 2PACz layer. Among them, the amount of 2PACz used is 100 μL, the rotation speed is 3000 rpm, the acceleration is 3000 rpm / s, and the time is 30 s. Then, anneal at 100 °C on a hot plate for 10 min to obtain a laminated structure of the conductive silicon substrate / hole transport layer;

[0096] Step d: Place the laminated structure obtained in step c in a mask for evaporating PbI2, and put the mask into a vacuum evaporation device for FAI deposition. The evaporation rate of FAI is The vacuum degree is 1.8×10 -3 Pa, the total evaporation thickness is 9 nm. After evaporation, a laminated structure of the conductive silicon substrate / hole transport layer / FAI is obtained;

[0097] Step e: Place the laminated structure of step d and the mask in a vacuum evaporation device, evacuate to 9.9×10 - 4 When Pa, adjust the rate of CsBr to The rate of PbI2 is The total evaporation thickness is 300 nm. After evaporation, a laminated structure of the conductive silicon substrate / hole transport layer / FAI / PbI2 is obtained;

[0098] Step f: Weigh 77.5 mg of FAI, 5.7 mg of MACl, and 12.6 mg of MABr and dissolve them in 1 mL of absolute ethanol. Shake at room temperature for 30 min to obtain a perovskite precursor solution;

[0099] Place the laminated structure of step e on a spin coater, and drop 100 μL of the perovskite precursor solution for spin coating. Among them, the rotation speed is 4000 rpm, the acceleration is 4000 rpm / s, and the time is 30 s to obtain a laminated structure of the conductive silicon substrate / hole transport layer / FAI / PbI2 / perovskite precursor solution layer;

[0100] Step g: Place the laminated structure obtained in step f on a hot plate with an environmental humidity of 70% and a temperature of 170 °C and anneal for 30 min to obtain a laminated structure of the conductive silicon substrate / hole transport layer / perovskite light-absorbing layer, where the thickness of the perovskite light-absorbing layer is 400 nm.

[0101] Step h: Place the laminated structure obtained in step g in a mask of the electron transport layer, and place the mask in a vacuum deposition device. The vacuum degree is 9.9×10 -4Evaporation of LiF, C60, and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was carried out at with thicknesses of 1 nm, 10 nm, and 1.5 nm respectively, to obtain a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer;

[0102] Step i: The stacked structure obtained in step h was placed in the chamber of atomic layer deposition for the preparation of the buffer layer. The vacuum was 20 Pa, the chamber temperature was 150 °C, the water source and tin source pressures were 50 Pa and 25 Pa respectively, and the number of cycles was 200, to obtain a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer;

[0103] Step j: The stacked structure obtained in step i was placed in the mask template of the ITO front composite layer, and then the mask template was placed in a magnetron sputtering instrument for the preparation of the ITO layer. The substrate temperature was 60 °C, the chamber pressure was 9.9×10 -4 Pa, the argon flow rate was 20 sccm, the oxygen flow rate was 0.3 sccm, the sputtering mode was DC magnetron sputtering, sputtering at 40 W for 6.5 min and 150 W for 4 min, to obtain a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer / front composite layer;

[0104] Step k: The stacked structure obtained in step j was placed in the mask templates of the positive electrode and the back electrode respectively, and then the mask templates were placed in a vacuum deposition device for the preparation of the electrodes. The vacuum was 7×10 -4 Pa, the thicknesses of the positive electrode and the back electrode were 400 nm and 200 nm respectively, to obtain a stacked structure of back electrode / conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer / front composite layer / positive electrode;

[0105] Step l: The stacked structure obtained in step k was placed on a mask template of 1.1×1.1 cm 2 and then the mask template was placed in a vacuum deposition device for the preparation of the antireflection layer. The vacuum was 9.9×10 -4 Pa, and the thickness was 100 nm, to obtain a perovskite silicon stacked cell.

[0106] Example 3

[0107] The perovskite solar cell in this example is a perovskite single-junction cell, and the conductive substrate uses a conductive glass substrate. The preparation method includes the following steps:

[0108] Step a: A 1.5×1.5 cm 2The ITO conductive glass substrate was successively placed in acetone and absolute ethanol and ultrasonically cleaned for 20 min. Subsequently, after the ITO conductive glass substrate was dried with nitrogen, it was placed in ozone for 20 min;

[0109] Step b: Place the ITO conductive glass substrate obtained in step a in a mask for sputtering the nickel oxide hole transport layer. Place the mask containing the ITO conductive glass substrate in a magnetron sputtering device. Evacuate to 9.5×10 -4 Pa, select the radio frequency magnetron sputtering mode, adjust the power to 85 W, set the argon gas flow rate to 25 sccm, and the sputtering time to 15 min;

[0110] Step c: After sputtering, transfer the ITO conductive glass substrate to a spin coater in a nitrogen glove box and spin coat the 2PACz layer. Among them, the amount of 2PACz used is 50 μL, the rotation speed is 2800 rpm, the acceleration is 2800 rpm / s, and the time is 26 s. Then, anneal on a hot stage at 95 °C for 8 min to obtain a stacked structure of the ITO conductive glass substrate / hole transport layer;

[0111] Step d: Place the stacked structure obtained in step c in a mask for evaporating PbI2. Place the mask in a vacuum evaporation device for MABr deposition. The evaporation rate of MABr is The vacuum degree is 1.6×10 -3 Pa, the total evaporation thickness is 7 nm. After evaporation, a stacked structure of ITO conductive glass substrate / hole transport layer / MABr is obtained;

[0112] Step e: Place the stacked structure and the mask of step d in a vacuum evaporation device. Evacuate to 9.5×10 - 4 Pa, adjust the rate of CsBr to The rate of PbI2 is The total evaporation thickness is 250 nm. After evaporation, a stacked structure of ITO conductive glass substrate / hole transport layer / MABr / PbI2 is obtained;

[0113] Step f: Weigh 75.5 mg of MABr, 5.5 mg of MACl, and 12.2 mg of MABr and dissolve them in 1 mL of absolute ethanol. Oscillate at room temperature for 25 min to obtain a perovskite precursor solution;

[0114] Place the stacked structure of step e on a spin coater, drop 75 μL of the perovskite precursor solution for spin coating. Among them, the rotation speed is 3400 rpm, the acceleration is 3400 rpm / s, and the time is 26 s to obtain a stacked structure of ITO conductive glass substrate / hole transport layer / MABr / PbI2 / perovskite precursor solution layer;

[0115] Step g: Anneal the stacked structure obtained in step f on a hot stage with an environmental humidity of 50% and a temperature of 150 °C for 20 min to obtain a stacked structure of ITO conductive glass substrate / hole transport layer / perovskite light-absorbing layer, wherein the thickness of the perovskite light-absorbing layer is 450 nm.

[0116] Step h: Place the stacked structure obtained in step g in a mask template of the electron transport layer, and place the mask template in a vacuum deposition device. When the vacuum degree is 9.5×10 -4 Pa, deposit LiF, C60 and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The deposition rates are 1.2 nm, 8 nm and 1.3 nm respectively to obtain a stacked structure of ITO conductive glass substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer;

[0117] Step i: Place the stacked structure obtained in step h in a mask template for silver evaporation, and then place the mask template in a vacuum deposition device. When the vacuum degree is 9.5×10 -4 Pa, evaporate the silver electrode. The deposition rate is about, and the deposition thickness is 120 nm to obtain a perovskite single-junction cell.

[0118] Example 4

[0119] The perovskite solar cell in this example is a perovskite-silicon tandem cell, and the conductive substrate uses a conductive silicon substrate. The preparation method includes the following steps:

[0120] Step a: Cut a 15×15 cm 2 silicon bottom cell into 2×2 cm 2 silicon wafers. The center of the silicon wafer has a 1.2×1.2 cm 2 substrate composite layer. Control the cutting precision error within 1 mm. Anneal the cut silicon wafers at 200 °C for 15 min to obtain a conductive silicon substrate, wherein the thickness of the conductive silicon substrate is 3 μm and the thickness of the substrate composite layer is 10 nm;

[0121] Step b: Place the conductive silicon substrate obtained in step a in a mask template for sputtering the nickel oxide hole transport layer. Place the mask template with the conductive silicon substrate in a magnetron sputtering device. When evacuated to 10.3×10 -4 Pa, select the radio frequency magnetron sputtering mode, adjust the power to 88 W, set the argon gas flow to 18 sccm, and the sputtering time to 14 min;

[0122] Step c: After sputtering is completed, transfer the conductive silicon substrate to a spin coater in a nitrogen glove box and spin coat the 2PACz layer. Here, the amount of 2PACz used is 100 μL, the rotation speed is 2850 rpm, the acceleration is 2850 rpm / s, and the time is 26 s. Then, anneal it on a hot plate at 100 °C for 10 min to obtain a stacked structure of the conductive silicon substrate / hole transport layer;

[0123] Step d: Place the stacked structure obtained in step c in a mask for depositing PbI2, and put the mask into a vacuum evaporation equipment for BACl deposition. The evaporation rate of BACl is The vacuum degree is 1.8×10 -3 Pa, the total evaporation thickness is 8 nm. After evaporation is completed, a stacked structure of the conductive silicon substrate / hole transport layer / BACl is obtained;

[0124] Step e: Place the stacked structure of step d and the mask in a vacuum evaporation equipment, evacuate to 10.3×10 - 4 Pa, adjust the rate of CsBr to be The rate of PbI2 is The total evaporation thickness is 310 nm. After evaporation is completed, a stacked structure of the conductive silicon substrate / hole transport layer / BACl / PbI2 is obtained;

[0125] Step f: Weigh 78.0 mg of BACl, 5.8 mg of MACl, and 12.4 mg of MABr, dissolve them in 1 mL of absolute ethanol, and shake at room temperature for 35 min to obtain a perovskite precursor solution;

[0126] Place the stacked structure of step e on a spin coater, drop 100 μL of the perovskite precursor solution for spin coating. Here, the rotation speed is 3500 rpm, the acceleration is 3500 rpm / s, and the time is 30 s to obtain a stacked structure of the conductive silicon substrate / hole transport layer / BACl / PbI2 / perovskite precursor solution layer;

[0127] Step g: Place the stacked structure obtained in step f on a hot plate with an environmental humidity of 70% and a temperature of 170 °C for annealing for 30 min to obtain a stacked structure of the conductive silicon substrate / hole transport layer / perovskite light-absorbing layer, where the thickness of the perovskite light-absorbing layer is 500 nm.

[0128] Step h: Place the stacked structure obtained in step g in a mask of the electron transport layer, and place the mask in a vacuum deposition equipment. When the vacuum degree is 10.3×10 -4 Pa, evaporate LiF, C60, and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the deposition rate is With thicknesses of 0.9 nm, 10 nm, and 1.4 nm respectively, a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer is obtained;

[0129] Step i: Place the stacked structure obtained in step h in the chamber of atomic layer deposition for the preparation of the buffer layer. The vacuum degree is 18 Pa, the chamber temperature is 155 °C, the water source and tin source pressures are 45 Pa and 20 Pa respectively, and the number of cycles is 220, obtaining a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer;

[0130] Step j: Place the stacked structure obtained in step i in the mask template of the ITO front composite layer, and then place the mask template in the magnetron sputtering instrument for the preparation of the ITO layer. The substrate temperature is 62 °C, the chamber pressure is 10×10 -4 Pa, the argon gas flow rate is 18 sccm, the oxygen gas flow rate is 0.45 sccm, the sputtering mode is DC magnetron sputtering, sputter at 35 W for 6 min and 140 W for 5 min, obtaining a stacked structure of conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer / front composite layer;

[0131] Step k: Place the stacked structure obtained in step j in the mask templates of the positive electrode and the back electrode respectively, and then place the mask templates in the vacuum deposition equipment for the preparation of the electrodes. The vacuum degree is 6×10 -4 Pa, the thicknesses of the positive electrode and the back electrode are 385 nm and 185 nm respectively, obtaining a stacked structure of back electrode / conductive silicon substrate / hole transport layer / perovskite light-absorbing layer / electron transport layer / buffer layer / front composite layer / positive electrode;

[0132] Step l: Place the stacked structure obtained in step k on a mask template of 1.1×1.1 cm 2 and then place the mask template in the vacuum deposition equipment for the preparation of the antireflection layer. The vacuum degree is 10.3×10 -4 Pa, and the thickness is 105 nm, obtaining a perovskite silicon stacked cell.

[0133] Comparative Example 1

[0134] This comparative example is basically the same as Example 1 in terms of raw materials, steps, and process conditions, with the only difference being:

[0135] During the preparation of the perovskite light-absorbing layer, the FAI layer is not prepared in advance, that is, step d and subsequent steps related to the FAI layer are not included.

[0136] Comparative Example 2

[0137] This comparative example is basically the same as Example 2 in terms of raw materials, steps, and process conditions, with the only difference being:

[0138] During the preparation of the perovskite light-absorbing layer, the FAI layer is not prepared in advance, that is, step d and subsequent steps related to the FAI layer are not included.

[0139] The solar cells prepared in Examples 1 to 4, Comparative Example 1, and Comparative Example 2 were subjected to relevant performance tests. The specific results are shown in Table 1. Among them, the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and conversion efficiency (PCE) were all measured under standard test conditions (AM1.5, 25 °C, 1000 W / m 2 )

[0140] Table 1 Battery performance of Examples 1 to 4, Comparative Example 1, and Comparative Example 2

[0141]

[0142]

[0143] It can be clearly seen from Table 1 that the battery performances of the perovskite single-junction cells in Examples 1 and 3 are significantly better than those in Comparative Example 1. The open-circuit voltage of Examples 1 and 3 can reach above 1.17 V, and the short-circuit current density can reach above 21 mA / cm 2 above, the fill factor can reach above 75%, and the conversion efficiency can reach above 19%.

[0144] Similarly, the battery performances of the perovskite / silicon tandem cells in Examples 2 and 4 are significantly better than those in Comparative Example 2. The open-circuit voltage of Examples 2 and 4 can reach above 1.85 V, and the short-circuit current density can reach above 20.7 mA / cm 2 above, the fill factor can reach above 80.1%, and the conversion efficiency can reach above 30.5%.

[0145] Figure 3 XRD patterns of the perovskite light-absorbing layer with pre-embedded FAI in Example 1 and the reference perovskite thin film. From Figure 3 it can be seen that the crystallinity of the perovskite light-absorbing layer in Example 1 is better than that of the reference perovskite thin film. There is residual PbI2 in the reference perovskite thin film, which will become a defect center to capture carriers, thus affecting the overall performance of the perovskite solar cell.

[0146] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: The steps include: Step 1: providing a conductive substrate; Step 2: forming a hole transport layer on the surface of the conductive substrate; Step 3: sequentially forming an A-site cationic compound layer, an inorganic skeleton and a perovskite precursor solution layer on the surface of the hole transport layer to obtain a laminated structure; The stacked structure is subjected to high temperature humidity annealing, so that the A-site cationic compound that penetrates into the inorganic skeleton reacts with PbI2 in the inorganic skeleton to generate a perovskite material, and the perovskite precursor solution that penetrates into the inorganic skeleton reacts with PbI2 to generate a perovskite material, thereby obtaining a perovskite light-absorbing layer; Step 4: forming an electron transport layer and a positive electrode in sequence on the surface of the perovskite light absorbing layer to obtain a perovskite solar cell; or, forming an electron transport layer, a buffer layer, a front composite layer and a positive electrode in sequence on the surface of the perovskite light absorbing layer, forming an anti-reflection layer between the two positive electrodes and on the surface of the front composite layer, and forming a back electrode on the back side of the conductive substrate to obtain a perovskite solar cell.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The A-site cationic compound is one or more of methyl ether iodide, methyl ether bromide, methyl ether chloride, methylammonium iodide, methylammonium bromide, methylammonium chloride, butylammonium iodide, butylammonium bromide and butylammonium chloride mixed in any proportion.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The thickness ratio of the A-site cationic compound layer, the inorganic skeleton and the perovskite light-absorbing layer is 6-11:200-320:350-550.

4. The method for preparing a perovskite solar cell according to any one of claims 1 to 3, characterized in that: The step 3 comprises the following steps: Step 31: evaporating an A-site cationic compound on the surface of the hole transport layer to form an A-site cationic compound layer; Step 32: evaporating cesium bromide and lead iodide on the surface of the A-site cationic compound layer to form an inorganic skeleton; Step 33: Spin-coating a perovskite precursor solution on the surface of the inorganic skeleton to form a perovskite precursor solution layer, and correspondingly forming a stacked structure on the surface of the hole transport layer; Step 34: perform high temperature humidity annealing on the laminated structure, so that the A-site cationic compound that penetrates into the inorganic skeleton reacts with PbI2 in the inorganic skeleton to generate a perovskite material, and the perovskite precursor solution that penetrates into the inorganic skeleton reacts with PbI2 to generate a perovskite material, thereby obtaining a perovskite light absorption layer.

5. The method for preparing a perovskite solar cell according to claim 4, characterized in that: In step 31, the evaporation rate of the A-position cationic compound is Vacuum degree is 1.5~1.8×10 -3 Pa.

6. The method for preparing a perovskite solar cell according to claim 4, characterized in that: In step 32, the evaporation rate of cesium bromide is The evaporation rate of the lead iodide is Vacuum degree is 9.5~10.5×10 -4 Pa.

7. The method for preparing a perovskite solar cell according to claim 4, characterized in that: The perovskite precursor solution comprises iodine methyl ether, methylammonium chloride, methylammonium bromide and an organic solvent.

8. The method for preparing a perovskite solar cell according to claim 7, characterized in that: The mass ratio of iodine methyl ether, methyl ammonium chloride and methyl ammonium bromide in the perovskite precursor solution is 75-80:5.5-6.0:12-13.

9. The method for preparing a perovskite solar cell according to claim 4, characterized in that: In step 34, the high temperature humidity annealing temperature is 150-170° C., the high temperature humidity annealing humidity is 50-75%, and the high temperature humidity annealing time is 20-30 minutes.

10. A perovskite solar cell, characterized in that: The perovskite solar cell is prepared by the preparation method according to any one of claims 1 to 9.

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