Recrystallization-based inverted perovskite solar cell and preparation method thereof

Abstract

The invention discloses an inverted perovskite solar cell based on recrystallization and a preparation method thereof, and belongs to the field of photovoltaic power generation, and the preparation method comprises the steps: preparing a precursor solution of a perovskite light absorption layer; spreading a precursor solution of the perovskite light absorption layer on the hole transport layer substrate, and forming a perovskite intermediate state through an anti-solvent process and annealing; and spin-coating isopropyl alcohol dispersion liquid of fenac salts on the perovskite intermediate state, and recrystallizing through secondary annealing to obtain the perovskite light absorption layer. According to the method, the high-quality perovskite light absorption layer is prepared by introducing fenac salt to induce secondary crystallization, and the problems of small crystal grains, large film residual stress, grain boundary defects and the like of the perovskite light absorption layer prepared by an anti-solvent spin coating method can be greatly improved through the secondary crystallization, so that the preparation difficulty of the anti-solvent spin coating process is greatly reduced; the photoelectric conversion efficiency of a small-area device and a large-area assembly is remarkably improved, and the method can be used for matching industrial production.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic power generation, and in particular to an inverted perovskite solar cell based on recrystallization and a preparation method thereof. Background Art

[0002] As a new generation of photovoltaic technology, perovskite solar cells (PSCs) have made great progress. The photoelectric conversion efficiency (PCE) of perovskite solar cells has rapidly increased from 3.8% to 26.7% in just about ten years, which is comparable to commercial polycrystalline silicon solar cells, cadmium telluride and copper indium gallium selenide thin-film solar cells.

[0003] At present, perovskite films are generally prepared by the precursor solution co-crystallization method, so its crystal quality (for example, morphology and surface coverage) is mainly determined by the regulation of the crystallization process. For example, the common methylamine lead iodide perovskite precursor randomly generates crystal nuclei during the crystallization process, and multi-center crystallization around these crystal nuclei forms unexpected lattice defects, resulting in segregation and film non-density. The generation of these defects will become the center of exciton recombination, causing non-radiative transition recombination, reducing the charge separation and transmission efficiency of perovskite solar cells, and even affecting the overall photoelectric conversion efficiency and stability. The defects generated in perovskite films under the action of light, heat, humidity, oxygen, and electricity lead to a serious increase in non-radiative recombination, thereby reducing the defect state density and perovskite crystal quality and hindering carrier transmission, ultimately making the device efficiency and stability subject to greater challenges, which is also the main factor hindering the successful commercialization of perovskite solar cells.

[0004] In addition, due to the temporal and spatial randomness of the generation of crystal nuclei, the reproducibility of the quality of perovskite films is also poor. Therefore, the crystallization of large-area perovskite films is uncontrollable, has poor uniformity, and has many intrinsic defects, resulting in serious lags in the efficiency and stability of large-area perovskite solar cell modules.

[0005] At present, the commonly used methods for regulating perovskite crystallization are mainly additives or anti-solvents to slow down the crystallization rate of perovskite and improve crystallization. Common additives include Lewis acids, Lewis bases and some polymer macromolecules. The introduction of additional components will lead to a decrease in the stability of perovskite solar cells. The anti-solvent method has very strict requirements on the time and amount of anti-solvent addition, resulting in poor uniformity of perovskite films.

[0006] As research has found, the introduction of recrystallization materials can cause poorly crystallized films to recrystallize. For example, a public application with publication number CN117545333A discloses an induction method and application based on the recrystallization of perovskite films. The isopropanol dispersion of iodoformamidine is used as a passivating agent, compounded into the perovskite film light-absorbing layer and induced perovskite recrystallization. By inducing the Oswald ripening process, the quality of the perovskite film is improved, the perovskite grain boundaries are passivated, the surface defect state density of the perovskite film is reduced, the proportion of effective radiation recombination is increased, and the rate of carrier injection into the counter electrode is increased, which is used to make large-area perovskite solar cells.

[0007] Therefore, developing recrystallization materials and post-treating the perovskite film prepared by the anti-solvent spin coating process can make the perovskite film crystallize again, solve the problems of small grains, large residual stress of the film, and many grain boundary defects in the perovskite film prepared by the anti-solvent, thereby effectively improving the photoelectric conversion efficiency and stability of perovskite solar cells. This is an urgent problem to be solved for the successful commercialization of perovskite solar cells. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides an inverted perovskite solar cell based on recrystallization and a preparation method thereof. The perovskite intermediate state is post-processed by introducing a recrystallization material, and a secondary crystallization is performed to construct a perovskite light absorption layer. The shortcomings of the perovskite intermediate state obtained by the anti-solvent spin coating method, such as small grains, large residual stress of the film, and many grain boundary defects, are greatly improved. At the same time, the method is also effective in large-area components, and further successful preparation of efficient and stable inverted perovskite solar cell devices and micro-components is achieved.

[0009] A method for preparing a recrystallized perovskite light absorbing layer comprises the following steps:

[0010] (1) preparing a precursor solution of a perovskite light absorbing layer;

[0011] (2) spreading the precursor solution of the perovskite light absorption layer prepared in step (1) on the hole transport layer substrate, and then forming a perovskite intermediate state through an anti-solvent process and annealing;

[0012] (3) Spin coating an isopropanol dispersion of fentanyl salts on the perovskite intermediate obtained in step (2), and performing secondary annealing for recrystallization to obtain a perovskite light absorption layer.

[0013] The present invention introduces fenates to post-treat the intermediate state of perovskite, and the characteristic group -COO- of fenates themselves reacts with Pb in poly(9-vinylcarbazole) (PVK) in the hole transport layer. +Due to the Pb-O interaction, the metal cations in the fenates can diffuse deeply in the perovskite film, reducing the energy barrier for crystal growth and inducing secondary crystallization, causing the poorly crystallized perovskite film to recrystallize. This secondary crystallization can greatly improve the grain size, grain boundary number and roughness of the perovskite film, thereby achieving high-quality perovskite film growth.

[0014] Preferably, the precursor solution of the perovskite light absorption layer contains crystals of ABX3 perovskite structure; wherein A is one or more of methylammonium cation, formamidinium cation, cesium ion, and rubidium ion, B is one or more of lead ion and tin ion, and X is one or more of chloride ion, bromide ion, iodide ion, and thiocyanate ion.

[0015] ABX3-type perovskite structured crystals have a high defect tolerance. The use of a precursor solution containing ABX3-type perovskite structured crystals to prepare a perovskite light absorption layer helps to improve the stability of perovskite solar cell devices; and by adjusting the components of ABX3, the band gap of the perovskite material can be changed, thereby improving the flexibility of the application of perovskite solar cell devices.

[0016] The preparation of the hole transport layer substrate comprises: firstly ultrasonically cleaning the substrate, drying it with high-pressure inert gas, and then irradiating it with ultraviolet light to obtain a cleaned substrate; then spin coating the hole transport layer material on the cleaned substrate and annealing it to prepare the hole transport layer substrate.

[0017] Preferably, the precursor solution is spread by spin coating, blade coating or slit coating.

[0018] Choosing a suitable method of spreading the precursor solution can greatly shorten the coating speed, improve the utilization rate of the precursor solution, and obtain a film with high precision and uniform wet thickness.

[0019] Further preferably, the precursor solution is spread by spin coating, the spin coating speed is 500 rpm to 2000 rpm, and the spin coating time is 20 s to 35 s.

[0020] Spin coating under the above spin coating process parameters can obtain a film with uniform distribution of perovskite components and appropriate thickness, which is convenient for subsequent anti-solvent process treatment.

[0021] Preferably, the anti-solvent process comprises: adding an anti-solvent dropwise 5s to 10s after the precursor solution begins to spread on the hole transport layer substrate for anti-dissolution, wherein the anti-solvent is anhydrous ether, chlorobenzene or anisole.

[0022] By using anhydrous ether, chlorobenzene or anisole as an anti-solvent for anti-dissolution, the crystallization process of the solute in the perovskite precursor solution is promoted during the solvent crystallization of the perovskite precursor solution.

[0023] Preferably, the annealing temperature in step (1) is 80-150° C., and the annealing time is 20 min-30 min.

[0024] The annealing treatment is performed at the above-mentioned annealing temperature and annealing time to obtain a stable perovskite intermediate state.

[0025] The annealing atmosphere is a nitrogen atmosphere.

[0026] Preferably, the fentanyl salt is diclofenac sodium (DS), diclofenac potassium (DP) or meclofenamate sodium (MS).

[0027] Diclofenac sodium, diclofenac potassium and meclofenamic acid sodium all have -COO- groups, which can react with Pb in the hole transport layer. + Pb-O interaction is generated, and potassium or sodium ions can diffuse deeply in the perovskite film, reducing the energy barrier for crystal growth and inducing secondary crystallization, causing the poorly crystallized perovskite film to recrystallize.

[0028] Preferably, the concentration of fentanyl salts is 0.1 mg / mL to 4 mg / mL.

[0029] Preferably, the rotation speed of spin coating the isopropanol dispersion of fentanyl salts is 1000 rpm to 6000 rpm, and the spin coating time is 5 s to 30 s.

[0030] By spin coating the recrystallized material within the above range, a perovskite film with uniform spin coating and uniform quality can be obtained, which is convenient for subsequent annealing treatment.

[0031] Preferably, the secondary annealing temperature is 80-150° C., and the secondary annealing time is 3 min-10 min.

[0032] The purpose of secondary annealing is to induce secondary crystallization of the intermediate state of perovskite to form a stable perovskite light absorption layer. The perovskite light absorption layer obtained by annealing temperature and annealing time in the above range has larger grains and smaller grain boundaries, which can effectively regulate secondary crystallization and improve the morphology of the perovskite light absorption layer.

[0033] The secondary annealing atmosphere is a nitrogen atmosphere.

[0034] The present invention also provides a perovskite light absorbing layer prepared by the method for preparing a perovskite light absorbing layer based on recrystallization.

[0035] Preferably, the perovskite light absorbing layer is FA 1-x-y MA x Cs y Pb(I 1-z Br z )3, where x=0~1, y=0~1, z=0~1.

[0036] Further preferably, the perovskite light absorbing layer is FA 0.95 MA 0.05 Cs 0.05 PbI3 and FA 0.94 MA 0.05 Cs 0.06 Pb(I 0.95 Br 0.05 )3.

[0037] In order to illustrate the influence of the photo-sintering preparation method on the photoelectric conversion efficiency of perovskite solar cell devices or micro-components, the present invention also provides a solar cell device or micro-component based on a perovskite light absorption layer, wherein the solar cell device or micro-component adopts an inverted structure, and the structural order is conductive substrate, hole transport layer, perovskite light absorption layer, electron transport layer, interface regulation layer and back electrode, wherein the perovskite light absorption layer is a perovskite light absorption layer prepared by the preparation method.

[0038] Preferably, the conductive substrate is ITO, and the square resistance of ITO is 15Ω and the transmittance is 85%.

[0039] Indium tin oxide (ITO) has a large bandgap width. Selecting an ITO conductive substrate with the above specifications can provide high visible light transmittance and near-infrared reflectivity, and has a very low resistivity, which can effectively improve conductivity.

[0040] The hole transport layer is [4-(7H-dibenzo[c,g]carbazole-7-yl)butyl]phosphonic acid (4PADCB) and has a thickness of 5nm to 50nm.

[0041] Single-molecule self-assembled phosphonates have high hole selectivity, high hole transport rate and low interface trap state density, and have a stable lattice structure. Selecting a hole transport layer of the above specifications can suppress light-induced halide segregation to enhance the stability of the device; and it also has molecular designability and excellent mechanical flexibility to match the industrial production of perovskite solar cell devices.

[0042] The electron transport layer is C60 with a thickness of 15nm to 25nm;

[0043] The electron transport layer has a wide band gap, a small refractive index and a high electron mobility, which can promote the effective separation of electrons and holes, reduce charge recombination and eliminate hysteresis.

[0044] The interface control layer is bathocuproin (BCP) with a thickness of 5nm to 20nm;

[0045] The interface control layer bathocuproin (BCP) can enhance carrier transport and prevent the dissociation of the surface structure of the perovskite crystal, thereby improving the stability of the device.

[0046] The back electrode is made of metal Ag, and has a thickness of 50nm to 100nm.

[0047] The back electrode metal Ag has good conductivity and stability. Selecting the metal Ag with the above thickness as the back electrode can solve the problem of back electrode contact in traditional devices and improve the efficiency and stability of the device.

[0048] The beneficial effects of the present invention are:

[0049] (1) The present invention prepares a high-quality perovskite light absorbing layer by introducing fentanyl to induce secondary crystallization. This secondary crystallization can greatly improve the problems of small grains, large film residual stress and grain boundary defects existing in the perovskite light absorbing layer prepared by the anti-solvent spin coating method.

[0050] (2) The efficiency of solar cell devices based on the prepared perovskite light absorption layer is further improved, and the photoelectric conversion efficiency of small-area devices and large-area components is significantly improved, which can be used to match industrial production.

[0051] (3) A high-quality perovskite active layer is obtained by inducing secondary crystallization, which greatly reduces the difficulty of the anti-solvent spin coating process and simplifies the preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The current-voltage curves of the perovskite solar cell device prepared in Comparative Example 1 without DS treatment and the perovskite solar cell device prepared in Example 1 after DS post-treatment.

[0053] Figure 2 The current-voltage curves of the perovskite solar cell micromodules prepared in Comparative Example 2 without DS treatment and prepared in Example 8 after DS post-treatment.

[0054] Figure 3 This is a scanning electron microscope image of the surface of the perovskite light absorption layer prepared in Comparative Example 1 without DS post-treatment.

[0055] Figure 4This is a scanning electron microscope image of the surface of the perovskite light absorption layer prepared in Example 1 and post-treated with DS.

[0056] Figure 5 Scanning electron microscope images of the cross-section of the perovskite light absorption layer prepared in Comparative Example 1 without DS treatment and prepared in Example 1 after DS treatment.

[0057] Figure 6 These are slightly incident wide-angle X-ray scattering images of the perovskite light absorption layer prepared in Comparative Example 1 without DS treatment and prepared in Example 1 after DS treatment.

[0058] Figure 7 The perovskite light absorption layer prepared in comparative example 1 without DS treatment and prepared in example 1 after DS treatment Linear fit of the curve.

[0059] Figure 8 The photoluminescence spectra of the perovskite light absorption layer prepared in Comparative Example 1 without DS treatment and the perovskite light absorption layer prepared in Example 1 after DS treatment.

[0060] Fig. 9 Box plots of the photoelectric conversion efficiency of the perovskite solar cell device prepared in Comparative Example 1 without DS treatment and the perovskite solar cell device prepared in Example 1 after DS treatment.

[0061] Fig.10 Graph showing the relationship between the open circuit voltage (Voc) and light intensity of the perovskite solar cell device prepared in Comparative Example 1 without DS treatment and the perovskite solar cell device prepared in Example 1 after DS treatment.

[0062] Fig.11 The 1000-hour light stability results of the perovskite solar cell device prepared in Comparative Example 1 without DS treatment and the perovskite solar cell device prepared in Example 1 after DS treatment at maximum power.

[0063] Fig.12 This is a graph showing the efficiency changes of the perovskite solar cell devices prepared in Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 after post-treatment at different DS concentrations.

[0064] Fig.13 Example 3 bromine-containing perovskite FA 0.94 MA 0.05 Cs 0.06 Pb(I 0.95 Br 0.05 )3 Efficiency distribution diagram and current-voltage curve diagram of devices with and without DS treatment.

[0065] Fig.14The device changes after treatment with different fentanyl salts in Example 4 are shown, namely diclofenac potassium (DP) and meclofenamic acid sodium (MS). DETAILED DESCRIPTION

[0066] The specific implementation of the present invention is further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are any processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art.

[0067] Example 1

[0068] Perovskite solar cell devices include a conductive substrate layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a passivation layer and a metal electrode from bottom to top.

[0069] The preparation steps of perovskite solar cell devices are as follows:

[0070] (1) An ITO conductive glass substrate with a square resistance of 15Ω, a transmittance of 85%, and a size of 1.96 cm×1.96 cm was selected as the substrate. Before use, the ITO conductive substrate was first ultrasonically cleaned with deionized water, acetone, and isopropanol, dried with nitrogen, and then cleaned by ultraviolet light for 30 minutes.

[0071] (2) Preparation of hole transport layer: 0.6 mg of [4-(7H-dibenzo[c,g]carbazole-7-yl)butyl]phosphonic acid (4PADCB) was dissolved in 2 mL of ethanol to prepare a hole transport layer solution. Then, 50 μL of the hole transport layer solution was added dropwise onto the ITO conductive substrate, and a layer of ultra-thin 4PADCB was deposited by spin coating at 3000 rpm for 30 seconds, and then annealed at 100°C for 10 minutes to prepare a hole transport layer.

[0072] (3) Preparation of perovskite light absorbing layer: The perovskite light absorbing layer is FA 0.95 MA 0.05 Cs 0.05 PbI3. The prepared perovskite precursor solution was dropped onto the hole transport layer, and the solution was spin-coated at 4000 rpm for 25 seconds. 500 μL to 800 μL of anhydrous ether (DE) was added to the perovskite wet film 10 seconds after the start of spin coating to dissolve it, and then annealed at 100 °C for 30 minutes to obtain the perovskite intermediate state.

[0073] Diclofenac sodium (DS) was dissolved in isopropyl alcohol solvent (IPA) to obtain a DS recrystallization passivation layer solution with a concentration of 1 mg / mL. The prepared DS recrystallization passivation layer solution was rotated at a speed of 3000 rpm for 30 seconds, spin-coated on the perovskite intermediate state, and then annealed at 100°C for 3 minutes to obtain a perovskite light absorption layer.

[0074] (4) Preparation of electron transport layer: The sample prepared in step (3) was placed in a vacuum evaporation coating device with a vacuum degree of 5×10 -4 After Pa, C60 was deposited at an evaporation rate of to obtain an electron transport layer with a thickness of 25 nm.

[0075] (5) Preparation of passivation layer: The prepared sample in step (40) is placed in a vacuum evaporation coating device, and the vacuum degree reaches 5×10 -4 After Pa, The BCP with a thickness of 6 nm was deposited at an evaporation rate of .

[0076] (6) Preparation of metal electrodes: The sample prepared in step (5) is placed in a vacuum evaporation coating device and the vacuum degree reaches 5×10 -4 After Pa, and Metal Ag was deposited at an evaporation rate of to obtain an Ag electrode coating with a thickness of 100 nm.

[0077] Based on the above steps, a perovskite solar cell device with an effective area of ​​0.04 cm 2 .

[0078] Example 2

[0079] The preparation steps of Example 2 are the same as those of Example 1, except that diclofenac sodium (DS) is dissolved in isopropyl alcohol solvent (IPA) to obtain a DS recrystallization passivation layer solution with a concentration of 0.5 mg / mL.

[0080] Example 3

[0081] The preparation steps of Example 3 are the same as those of Example 1, except that diclofenac sodium (DS) is dissolved in isopropyl alcohol solvent (IPA) to obtain a DS recrystallization passivation layer solution with a concentration of 2 mg / mL.

[0082] Example 4

[0083] The preparation steps of Example 4 are the same as those of Example 1, except that diclofenac sodium (DS) is dissolved in isopropyl alcohol solvent (IPA) to obtain a DS recrystallization passivation layer solution with a concentration of 4 mg / mL.

[0084] Example 5

[0085] The preparation steps of Example 5 are the same as those of Example 1, except that: the perovskite light absorption layer is FA 0.94 MA 0.05 Cs 0.06 Pb(I 0.95 Br 0.05 )3.

[0086] Example 6

[0087] The preparation steps of Example 6 are the same as those of Example 1, except that diclofenac sodium (DS) is replaced by diclofenac potassium (DP) dissolved in isopropyl alcohol solvent (IPA).

[0088] Example 7

[0089] The preparation steps of Example 7 are the same as those of Example 1, except that diclofenac sodium (DS) is replaced by meclofenamic acid sodium (MS) and dissolved in isopropyl alcohol solvent (IPA).

[0090] Example 8

[0091] Perovskite solar cell micromodules include a conductive substrate layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a passivation layer and a metal electrode from bottom to top.

[0092] The steps for preparing perovskite solar cell micromodules are as follows:

[0093] (1) An ITO conductive glass substrate with a square resistance of 15Ω, a transmittance of 85%, and a size of 5 cm×5 cm was selected as the substrate. After laser scribing P1, it was ultrasonically cleaned with deionized water, acetone, and isopropanol in sequence, dried with nitrogen, and then cleaned by ultraviolet light for 30 minutes.

[0094] (2) Preparation of hole transport layer: 0.6 mg of [4-(7H-dibenzo[c,g]carbazole-7-yl)butyl]phosphonic acid (4PADCB) was dissolved in 2 mL of ethanol to prepare a hole transport layer solution. Then, 400 μL of the hole transport layer solution was added dropwise onto the ITO conductive substrate, and a layer of ultra-thin 4PADCB was deposited by spin coating at 3000 rpm for 30 seconds, and then annealed at 100° C. for 10 minutes to prepare a hole transport layer.

[0095] (3) Preparation of perovskite light absorbing layer: The perovskite light absorbing layer is FA 0.95 MA 0.05 Cs 0.05 PbI3. The prepared perovskite precursor solution was dropped onto the hole transport layer, and spin-coated at 4000 rpm for 25 seconds. About 2 mL of anhydrous ether (DE) was added to the perovskite wet film 10 seconds after the start of spin coating to dissolve it, and then annealed at 100 ° C for 30 minutes to obtain the perovskite intermediate state;

[0096] Diclofenac sodium (DS) was dissolved in isopropyl alcohol solvent (IPA) to obtain a DS recrystallization passivation layer solution with a concentration of 10 mg / mL. The prepared DS recrystallization passivation layer solution was rotated at a speed of 3000 rpm for 30 seconds, spin-coated on the perovskite intermediate state, and then annealed at 100°C for 3 minutes to obtain a perovskite light absorption layer.

[0097] (4) Preparation of electron transport layer: The sample prepared in step (3) was placed in a vacuum evaporation coating device with a vacuum degree of 5×10 -4 After Pa, C60 was deposited at an evaporation rate of to obtain an electron transport layer with a thickness of 25 nm.

[0098] (5) Preparation of passivation layer: The sample prepared in step (4) was placed in a vacuum evaporation coating device with a vacuum degree of 5×10 -4 After Pa, The BCP with a thickness of 6 nm was deposited at an evaporation rate of , and then P2 was processed by laser scribing.

[0099] (6) Preparation of metal electrodes: The sample prepared in step (5) is placed in a vacuum evaporation coating device and the vacuum degree reaches 5×10 -4 After Pa, and The Ag electrode coating with a thickness of 100 nm was obtained by depositing metal Ag at an evaporation rate of . Then, P3 and P4 were formed by laser scribing.

[0100] Based on the above steps, a perovskite solar cell micromodule was obtained with an aperture area of ​​10.24 cm 2 .

[0101] Comparative Example 1

[0102] The preparation process without DS post-treatment. The perovskite solar cell device includes a conductive substrate layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a passivation layer and a metal electrode from bottom to top.

[0103] The preparation steps of perovskite solar cell devices are as follows:

[0104] (1) An ITO conductive glass substrate with a square resistance of 15Ω, a transmittance of 85%, and a size of 1.96 cm×1.96 cm was selected as the substrate. Before use, the ITO conductive substrate was first ultrasonically cleaned with deionized water, acetone, and isopropanol, dried with nitrogen, and then cleaned by ultraviolet light for 30 minutes.

[0105] (2) Preparation of hole transport layer: 0.6 mg of [4-(7H-dibenzo[c,g]carbazole-7-yl)butyl]phosphonic acid (4PADCB) was dissolved in 2 mL of ethanol to prepare a hole transport layer solution. Then, 50 μL of the hole transport layer solution was added dropwise onto the ITO conductive substrate, and a layer of ultra-thin 4PADCB was deposited by spin coating at 3000 rpm for 30 seconds, and then annealed at 100°C for 10 minutes to prepare a hole transport layer.

[0106] (3) Preparation of perovskite light absorbing layer: The perovskite light absorbing layer is FA 0.95 MA 0.05 Cs 0.05 PbI3). The prepared perovskite precursor solution was dripped onto the hole transport layer, and the film was spin-coated at 4000 rpm for 25 seconds. 0.5 mL of anhydrous ether (DE) was added to the perovskite wet film 10 seconds after the start of spin coating to dissolve it, and then annealed at 100 ° C for 30 minutes to obtain the perovskite intermediate state, which is the perovskite light absorption layer.

[0107] (4) Preparation of electron transport layer: The sample prepared in step (3) was placed in a vacuum evaporation coating device with a vacuum degree of 5×10 -4 After Pa, C60 was deposited at an evaporation rate of to obtain an electron transport layer with a thickness of 25 nm.

[0108] (5) Preparation of passivation layer: The sample prepared in step (4) was placed in a vacuum evaporation coating device with a vacuum degree of 5×10 -4 After Pa, The BCP with a thickness of 6 nm was deposited at an evaporation rate of .

[0109] (6) Preparation of metal electrodes: The sample prepared in step (5) is placed in a vacuum evaporation coating device and the vacuum degree reaches 5×10 -4 After Pa, and Metal Ag was deposited at an evaporation rate of to obtain an Ag electrode coating with a thickness of 100 nm.

[0110] Based on the above steps, a perovskite solar cell device with an effective area of ​​0.04 cm 2 .

[0111] Comparative Example 2

[0112] The preparation steps of Comparative Example 2 are the same as those of Example 8, except that the perovskite light absorbing layer is not post-treated with DS.

[0113] Test Example 1

[0114] The photoelectric properties of the perovskite solar cells prepared in Examples 1 and 8 and Comparative Examples 1 and 2 were analyzed.

[0115] Under the conditions of simulated AM1.5 sunlight (light intensity of 100mW / cm 2 ) The current-voltage curves (JV) of the perovskite solar cell devices prepared in Example 1 and Comparative Example 1 were tested respectively, with a reverse scan of 1.5V-0.5V and a scan rate of 20mV / s (device effective area: 0.04cm 2 ), the results are shown in Table 1 and Figure 1 .

[0116] Table 1 Photoelectric performance parameters of perovskite solar cell devices (effective area: 0.04 cm 2 )

[0117]

[0118] Under the conditions of simulated AM1.5 sunlight (light intensity of 100mW / cm 2 ) The current-voltage curves (JV) of the perovskite solar cell micromodules prepared in Example 2 and Comparative Example 2 were tested respectively, with a reverse scan of 6V-0.5V and a scan rate of 20mV / s (device effective area: 10.24cm 2 ) The results are shown in Table 2 and Figure 2 .

[0119] Table 2 Photoelectric performance parameters of perovskite solar cell micromodules (aperture area: 10.24 cm 2 )

[0120]

[0121] From Tables 1, 2 and Figure 1 , 2 It can be seen that the short-circuit current density (Jsc), open-circuit voltage (Voc) and Faraday efficiency (FF) of the perovskite solar cell treated with DS are all improved. 2 ) has a photoelectric efficiency (25.52%) higher than that of the cell device without DS treatment in Comparative Example 1 (23.62%). Meanwhile, the micromodule treated with DS in Example 2 (aperture area: 10.24 cm 2 ) has a photoelectric efficiency (20.27%) higher than that of the untreated micromodule in Comparative Example 2 (18.05%), proving that DS post-treatment improves the photoelectric performance of the perovskite cell.

[0122] Test Example 2

[0123] The microscopic morphology of the perovskite light absorbing layer films prepared in the examples and comparative examples was characterized using a scanning electron microscope (SEM).

[0124] Figure 3 This is a SEM image of the surface of the perovskite light absorption layer prepared in Comparative Example 1 without DS post-treatment. Figure 4 This is a SEM image of the surface of the perovskite light absorption layer prepared in Example 1 after DS post-treatment. Figure 3 and Figure 4 By comparison, it can be seen that the perovskite film after DS treatment has larger grains and fewer grain boundaries;

[0125] Figure 5 SEM images of the cross-section of the perovskite light absorption layer prepared in Comparative Example 1 without DS post-treatment and prepared in Example 1 after DS post-treatment, wherein: Figure 5 The left side is a SEM image of the cross section of the perovskite light absorption layer prepared in Comparative Example 1 without DS post-treatment. Figure 5 The right side is a SEM image of the cross section of the perovskite light absorption layer prepared in Comparative Example 1 after DS post-treatment. Figure 5 It can be observed that the grains of the sample after DS treatment prepared in Example 1 are significantly larger in cross section, and more grains show vertical orientation, indicating that DS treatment can effectively regulate secondary crystallization and change the morphology of the film.

[0126] Test Example 3

[0127] The perovskite light absorption layer films prepared in the examples and comparative examples were analyzed by slightly incident wide-angle X-ray scattering. Figure 6 Shown are slightly incident wide-angle X-ray scattering spectra of the perovskite light absorption layer prepared without DS post-treatment and after DS post-treatment prepared in Example 1.

[0128] Depend on Figure 6 The results show that DS treatment has a certain regulatory effect on the crystallization of perovskite films, causing perovskite to grow preferentially along the (100) plane.

[0129] like Figure 7 The perovskite light absorbing layer is shown. The linear fitting diagram of the curve is Figure 7 The results show that the residual stress of the perovskite film is significantly reduced after DS treatment.

[0130] Test Example 4

[0131] The photoluminescence spectra (PL) of the perovskite light absorbing layer films prepared in the examples and comparative examples were analyzed to characterize the defect density, such as Figure 8Shown are photoluminescence spectra (PL spectra) of the perovskite light absorption layer prepared in Comparative Example 1 without DS post-treatment and prepared in Example 1 after DS post-treatment.

[0132] Depend on Figure 8 The results show that the emission intensity of the perovskite light absorption layer film after DS treatment is much higher than that of the perovskite light absorption layer film without DS treatment, indicating that DS suppresses the non-radiative recombination of carriers.

[0133] Test Example 5

[0134] The performance of the perovskite solar cell devices prepared in the examples and comparative examples were characterized.

[0135] Fig. 9 The box plots are of the photoelectric conversion efficiency of the perovskite solar cell without DS treatment prepared in Comparative Example 1 and after DS treatment prepared in Example 1. It can be clearly seen from the figure that DS treatment can significantly improve the photoelectric conversion efficiency of the perovskite solar cell device.

[0136] Fig.10 is a graph showing the relationship between Voc and light intensity of the perovskite solar cell prepared in Comparative Example 1 without DS treatment and prepared in Example 1 after DS treatment; Fig.10 It can be seen that the slope of the perovskite solar cell device after DS treatment prepared in Example 1 is smaller than the slope of the perovskite solar cell device without DS treatment prepared in Comparative Example 1, indicating that the defect-assisted recombination of the perovskite solar cell device after DS treatment prepared in Example 1 is significantly reduced.

[0137] Fig.11 The light stability results of the perovskite solar cell device prepared in Comparative Example 1 without DS treatment and the perovskite solar cell device prepared in Example 1 after DS treatment at maximum power. Fig.11 It can be seen that the perovskite solar cell device treated with DS still maintains 91% of the initial photoelectric conversion efficiency after aging for 1000 hours, while the PCE of the perovskite solar cell device without DS treatment rapidly decays to 81% of the initial after aging for 1000 hours.

[0138] Test Example 6

[0139] In Examples 1 to 4, DS solutions of different concentrations (0.5 mg / ml, 1.0 mg / ml, 2.0 mg / ml, 4 mg / ml) were used to post-treat the perovskite film. Fig.12 As shown, the efficiency of perovskite solar cell devices first increases with the increase of DS concentration, reaching the highest point at 1.0 mg / ml. Further increasing the DS concentration will reduce the efficiency of the device.

[0140] Test Example 7

[0141] In Example 5, FA for the bromine-containing perovskite system 0.94 MA 0.05 Cs 0.06 Pb(I 0.95 Br 0.05 )3, studied whether DS post-processing is effective. Fig.13 As shown in the figure, after treatment with 1 mg / ml DS, the efficiency of the bromine-containing perovskite solar cell device also increased from an average efficiency of 22.5% to 24.5%, and the champion efficiency point also exceeded 25%. It can be seen from the voltage-current curve that the open circuit voltage after DS treatment has also increased significantly.

[0142] Test Example 8

[0143] In Examples 6 and 7, FA 0.95 MA 0.05 Cs 0.05 The post-treatment effects of different fentanyl salts were studied. Fig.14 As shown, after treatment with diclofenac potassium (DP) and meclofenamic acid sodium (MS), the efficiency of perovskite solar cell devices has been improved to varying degrees compared with the standard, indicating that treatment with diclofenac potassium (DP) and meclofenamic acid sodium (MS) can also effectively improve the efficiency of perovskite solar cell devices.

Claims

1. A method for preparing a recrystallized perovskite light absorbing layer, characterized in that: The following steps are involved: (1) preparing a precursor solution of a perovskite light absorbing layer; (2) spreading the precursor solution of the perovskite light absorption layer prepared in step (1) on the hole transport layer substrate, and then forming a perovskite intermediate state through an anti-solvent process and annealing; (3) Spin coating an isopropanol dispersion of fentanyl salts on the perovskite intermediate state obtained in step (2), and performing secondary annealing for recrystallization to obtain a perovskite light absorption layer.

2. The method for preparing a perovskite light absorbing layer according to claim 1, characterized in that: The precursor solution is spread by spin coating, scraping coating or slit coating, wherein the spin coating speed is 500 rpm to 2000 rpm and the spin coating time is 20 s to 35 s.

3. The method for preparing a perovskite light absorbing layer according to claim 1, characterized in that: 5s to 10s after the precursor solution begins to spread on the hole transport layer substrate, an anti-solvent is added dropwise for anti-dissolution, wherein the anti-solvent is anhydrous ether, chlorobenzene or anisole.

4. The method for preparing a perovskite light absorbing layer according to claim 1, characterized in that: The annealing temperature in step (1) is 80-150° C., and the annealing time is 20-30 minutes.

5. The method for preparing a perovskite light absorbing layer according to claim 1, characterized in that: The fenate salt is diclofenac sodium, diclofenac potassium or meclofenamic acid sodium, and the concentration of the fenate salt is 0.1 mg / mL to 4 mg / mL.

6. The method for preparing a perovskite light absorbing layer according to claim 1, characterized in that: The rotation speed of the spin coating of the isopropanol dispersion of fentanyl salts is 1000 rpm to 6000 rpm, and the spin coating time is 5s to 30s.

7. The method for preparing a perovskite light absorbing layer according to claim 1, characterized in that: The temperature of the secondary annealing is 80-150° C., and the secondary annealing time is 3 min-10 min.

8. A perovskite light absorbing layer prepared according to the method for preparing a perovskite light absorbing layer based on recrystallization according to any one of claims 1 to 7.

9. The perovskite light absorbing layer according to claim 8, characterized in that: The perovskite light absorbing layer is FA 1-x- y MA x Cs y Pb(I 1-z Br z )3, where x=0~1, y=0~1, z=0~1.

10. A solar cell device or micromodule comprising the perovskite light absorption layer according to claim 8 or 9, characterized in that: The solar cell device or micro-module adopts an inverted structure, and the structural order is conductive substrate, hole transport layer, perovskite light absorption layer, electron transport layer, interface regulation layer and back electrode.

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