A halide amine salt treatment based photovoltaic device and its preparation method and application

Abstract

The application discloses a photovoltaic device based on halide amine salt treatment and a preparation method and application thereof. The photovoltaic device is a normal device or an inverted device. In the preparation, a short-chain halide amine salt OAI is spin-coated on a two-dimensional perovskite layer, an oriented two-dimensional perovskite modification layer is generated through in-situ reaction, surface defects of the thin film are passivated, the built-in electric field of the device is increased to promote extraction and separation of carriers, efficient transportation of the carriers is realized, and a high-efficiency and stable two-dimensional perovskite device is realized. The application has low cost, and the obtained photovoltaic device exhibits excellent photoelectric conversion efficiency and stability, has a semi-transparent feature, and can be applied to perovskite batteries, semi-transparent photovoltaic glass, photovoltaic intelligent windows, flexible thin film devices and the like, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of novel semiconductor optoelectronics, specifically relating to a method for fabricating highly efficient and stable two-dimensional perovskite photovoltaic devices using liquid phase epitaxy combined with solvent engineering and additive engineering. The perovskite solar cells fabricated using this method can be applied to photovoltaic devices (including indoor and outdoor photovoltaic devices), semi-transparent photovoltaic glass, photovoltaic smart windows, flexible thin-film devices, etc., and have broad application prospects. Background Technology

[0002] In recent years, environmental and energy problems have become increasingly serious. As an emerging green energy source, solar energy has received more and more attention due to its advantages such as being inexhaustible, pollution-free, and readily available.

[0003] Perovskite solar cells (PSCs) have rapidly become one of the hottest topics in the photovoltaic industry due to their high power conversion efficiency (PCE) and low-cost production. Among various PSCs, typical three-dimensional (3D) perovskite-based solar cells offer high PCE, but they suffer from severe instability, which limits their practical applications. Compared to 3D perovskites, 2D perovskites contain larger, less volatile, and generally more hydrophobic halide cations, resulting in significantly improved thermal, chemical, and environmental stability. However, the efficiency of 2D perovskite cells is lower than that of 3D perovskite cells. A quasi-2D-2D perovskite-based solar cell and its fabrication method (application number 202210428165.3) proposes to improve the stability of perovskite devices by coating 2MeOPEAI to prepare a quasi-2D-2D heterojunction. Although the device stability is significantly improved, the random orientation of the formed 2D perovskite ((2MeOPEA)2PbI4) still results in low carrier transport efficiency. Therefore, it is urgent to improve the efficiency of two-dimensional perovskite solar cells in order to promote their commercialization. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of current technologies by proposing a photovoltaic device based on halide amine salt treatment, its fabrication method, and its applications. This method involves spin-coating a short-chain halide amine salt (OAI) onto a two-dimensional perovskite layer. Through in-situ reaction, a well-oriented two-dimensional perovskite modification layer is generated, which passivates surface defects, increases the built-in electric field of the device to promote carrier extraction and separation, and achieves efficient carrier transport, resulting in a highly efficient and stable two-dimensional perovskite device. This invention is low-cost, and the photovoltaic device prepared by this method exhibits excellent photoelectric conversion efficiency and stability, while also possessing semi-transparency. It can be applied to photovoltaic devices (including indoor and outdoor photovoltaic devices), semi-transparent photovoltaic glass, photovoltaic smart windows, flexible thin-film devices, etc., and has broad application prospects.

[0005] The technical solution of this invention is as follows:

[0006] A photovoltaic device based on halide amine salt treatment is disclosed. The photovoltaic device can be a forward-mounted device or an inverted device. In the forward-mounted device, the components from bottom to top are a transparent conductive substrate, an electron transport layer, a two-dimensional perovskite active layer, a two-dimensional perovskite modification layer, a hole transport layer, and a counter electrode. In the inverted device, the components from bottom to top are a transparent conductive substrate, a hole transport layer, a two-dimensional perovskite active layer, a two-dimensional perovskite modification layer, an electron transport layer, and a counter electrode.

[0007] The general structural formula of the two-dimensional perovskite active layer is A(FA). n-1 Pb n I 3n+1 The preferred n value is 1 to 20, where A is a +2 valence halide cation, FA + It is a formamidinium cation; its thickness is 100–1000 nm;

[0008] The +2 valence state halide cation mentioned above is specifically butanediamine ion (BDA). 2+ ), hexamethylenediamine ion (HDA) 2+ ) or propylenediamine ions (PDA) 2+ );

[0009] The general structural formula of the two-dimensional perovskite modified layer material is [M2(FA)]. a-1 Pb a I 3a+1 ] x [N((FA) b- 1Pb b I 3b+1 ] 1-x Where a and b take values ​​from 1 to 3, x = 0 to 1; M is OA + N is BDA 2+ HDA 2+ or PDA 2+ The thickness is 1–20 nm.

[0010] The transparent conductive substrate is preferably one of fluorine-doped SnO2 conductive glass (FTO), indium tin oxide transparent conductive film glass (ITO), PET / ITO (PET is polyethylene terephthalate), and PEN / ITO (PEN is polyethylene naphthalate).

[0011] The electron transport layer is at least one of titanium dioxide (TiO2), TiO2-SnO2, tin dioxide (SnO2), chlorine-doped titanium dioxide, ZnO-TiO2, and ZnO-SnO2. The electron transport layer of the inverting device is methyl [6,6]-phenyl C61-butyrate (PCBM) or 60(C 60At least one of nano zinc oxide (ZnO); with a thickness of 5–200 nm;

[0012] The hole transport layer of the upright device is one of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), or copper cyanide (CuPc); the hole transport layer of the inverted device is poly-3-hexylthiophene (P3HT) or nickel oxide (NiO). x At least one of poly(2,3-dihydrothiopheno-1,4-dioxin)-poly(styrene sulfonate) (PEDOT:PSS); with a thickness of 30-500 nm;

[0013] The electrode is one or more of carbon, gold, and silver; the electrode of the inverting device is one or more of chromium, copper, and silver; when the electrode is metal, the thickness is 50-120 nm; when the electrode is carbon, the thickness is 5-30 μm.

[0014] The method for fabricating a positive-position two-dimensional perovskite photovoltaic device based on halide amine salt treatment includes the following steps:

[0015] Step 1: Spin-coat an electron transport layer precursor solution onto a conductive glass substrate, and then spin-coat a passivation agent solution for interface treatment to prepare the electron transport layer;

[0016] The electron transport layer precursor solution is an aqueous solution of titanium tetrachloride with a volume percentage concentration of 0.01-1%.

[0017] The solute of the passivating agent is one or both of potassium chloride and cesium chloride; the concentration is 0.1-5 mg / ml;

[0018] Step 2: Spin-coat the target component A (FA) onto the surface of the electron transport layer using a spin coater. n-1 Pb n I 3n+1 A two-dimensional perovskite precursor solution was subjected to low-pressure treatment followed by annealing to obtain a two-dimensional perovskite layer; the perovskite precursor solution contained Pb 2+ The concentration is 0.2–2 mol / L;

[0019] The spin coating speed is 1000-10000 rpm / s, and the spin coating time is 1-20s;

[0020] The solvent for the two-dimensional perovskite includes at least one of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and dimethylacetamide (DMAc).

[0021] The vacuum degree of the two-dimensional perovskite low-pressure auxiliary equipment is 1-100 Pa, and the processing time is 1-120 s; the annealing temperature is 50-200℃, and the annealing time is 1-60 min.

[0022] Step 3: Spin-coat a halide amine salt solution onto the surface of the two-dimensional perovskite layer to obtain a two-dimensional perovskite modified layer;

[0023] The concentration of the halide amine salt solution is 0.1–20 mg / ml, the solute is OAI, and the solvent is isopropanol;

[0024] The spin coating speed is 1000-10000 rpm / s, the spin coating time is 10-60s, the annealing temperature is 25-150℃, and the annealing time is 0-30min; when the annealing time is 0, it means that no annealing step is performed.

[0025] Step 4: Spin-coat the hole transport layer precursor solution onto the surface of the two-dimensional perovskite modified layer to prepare the hole transport layer;

[0026] Step 5: Deposit a counter electrode on the surface of the hole transport layer by vapor deposition.

[0027] The method for fabricating an inverted device of a two-dimensional perovskite photovoltaic device based on halide amine salt treatment includes the following steps:

[0028] Step 1: Spin-coat the hole transport layer precursor solution onto a conductive glass substrate to prepare the hole transport layer;

[0029] Step 2: Spin-coat the target component A (FA) onto the surface of the hole transport layer using a spin coater. n-1 Pb n I 3n+1 A two-dimensional perovskite precursor solution was subjected to low-pressure treatment followed by annealing to obtain a two-dimensional perovskite layer; the perovskite precursor solution contained Pb 2+ The concentration is 0.2–2 mol / L;

[0030] The spin coating speed is 1000-10000 rpm / s, and the spin coating time is 1-20s;

[0031] The solvent for the two-dimensional perovskite includes at least one of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and dimethylacetamide (DMAc);

[0032] The vacuum degree of the two-dimensional perovskite low-pressure auxiliary equipment is 1-100 Pa, and the processing time is 1-120 s; the annealing temperature is 50-200℃, and the annealing time is 1-60 min.

[0033] Step 3: Spin-coat a halide amine salt solution onto the surface of the two-dimensional perovskite layer to obtain a two-dimensional perovskite modified layer;

[0034] The concentration of the halide amine salt solution is 0.1–20 mg / ml, the solute is OAI, and the solvent is isopropanol;

[0035] The spin coating speed is 1000-10000 rpm / s, the spin coating time is 10-60s, the annealing temperature is 25-150℃, and the annealing time is 0-30min; when the annealing time is 0, it means that no annealing step is performed.

[0036] Step 4: Spin-coat the electron transport layer precursor solution onto the surface of the two-dimensional perovskite modified layer, and then spin-coat the passivation agent solution for interface treatment to prepare the electron transport layer;

[0037] The concentration of the electron transport layer precursor solution is 1-50 mg / ml, and the solvent is chlorobenzene;

[0038] The passivating agent is at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and polyethyleneimine (PEI); the concentration of the passivating agent solution is 0.1-5 mg / ml, and the solvent is isopropanol;

[0039] Step 5: Deposit the counter electrode on the surface of the electron transport layer by vapor deposition.

[0040] The photovoltaic devices based on halide amine salt treatment are applied to perovskite cells, semi-transparent photovoltaic glass, photovoltaic smart windows, or flexible films.

[0041] The essential features of this invention are:

[0042] This invention uses a wide-bandgap semiconductor DJ phase two-dimensional perovskite material A(FA). n-1 Pb n I 3n+1 (Preferred n value is 1-20). By adjusting the composition, chlorides or fluorides are added as additives to the perovskite precursor solution. Chlorides or fluorides can effectively passivate defects on the film surface and delay crystallization. Low-pressure assisted treatment ensures uniform solvent evaporation during film annealing, forming large-sized grains. Combined with chemical bath growth, an electron transport layer with excellent electron extraction capability is prepared. long Chain halide amine saltsBy treating a two-dimensional perovskite layer and generating a two-dimensional perovskite modification layer through in-situ reaction, a heterojunction is formed after treatment. This effectively passivates surface defects in the thin film, increases the built-in electric field of the perovskite, and promotes the extraction and separation of charge carriers. A two-dimensional perovskite (n=2~10) solar cell that balances material stability and photoelectric performance was prepared. At the same time, the prepared perovskite solar cell also has a semi-transparent feature, which can be applied to photovoltaic devices (including indoor and outdoor photovoltaic devices), semi-transparent photovoltaic glass, photovoltaic smart windows, flexible thin film devices, etc., and has broad application prospects.

[0043] The beneficial effects of the present invention are:

[0044] 1. The method for fabricating a photovoltaic device provided by this invention is simple, feasible, and low in cost, and can be applied to large-area fabrication.

[0045] 2. This invention treats a two-dimensional perovskite layer with long-chain halide amine salts. The in-situ reaction-formed (OA)₂PbI₄ two-dimensional perovskite modification layer has a good vertical orientation, which can passivate interface defects and ensure efficient carrier transport. This results in high photoelectric conversion efficiency of the device under indoor and simulated sunlight. The PCE under standard simulated sunlight intensity exceeds 22%, while the efficiency of the device without long-chain amine salt treatment is 18%. The PCE under weak light intensity reaches 42%, while the efficiency of the device without long-chain amine salt treatment is 38%. Both exceed the efficiency of similar devices reported before and have broad application prospects in the field of photovoltaic power generation.

[0046] 3. The perovskite solar cells prepared by this invention have both high photoelectric conversion efficiency and high transmittance, and can be applied to semi-transparent devices, photovoltaic smart windows, etc.

[0047] 4. The photovoltaic device prepared by the method of this invention has good environmental stability. At room temperature, after 40 days (see...), it exhibits good environmental stability. Figure 7 It still retains 99% of its initial efficiency after that. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of a photovoltaic device according to an embodiment of the present invention.

[0049] Figure 2 The images show the X-ray diffraction patterns of the perovskite thin films in Examples 1-4.

[0050] Figure 3 The efficiency graphs of the perovskite devices in Examples 2-4 under low indoor light conditions are shown.

[0051] Figure 4 The graphs show the efficiency of the perovskite devices in Examples 2-4 under standard illumination.

[0052] Figure 5This is a transmittance curve of the perovskite device in Example 1.

[0053] Figure 6 The efficiency graph of the perovskite device prepared in Example 1 under standard illumination is shown.

[0054] Figure 7 The stability diagram is shown for the perovskite device prepared in Example 1. Detailed Implementation

[0055] The present invention will be further described below with reference to embodiments.

[0056] The device structure of the perovskite photovoltaic device of the present invention is as follows: Figure 1 As shown, this method utilizes a chemical bath growth method to prepare an electron transport layer. A mixed solution of lead halide and amine halide salts is prepared, and the perovskite film precursor deposited on the substrate is treated using a low-pressure auxiliary device. A well-crystallized perovskite film is formed by isothermal heating annealing. Subsequently, long-chain amine halide salts are spin-coated onto the perovskite layer to further reduce interfacial surface defects and increase the built-in electric field. A hole transport layer is prepared by spin-coating Spiro-OMeTAD, and finally, a metal electrode is deposited by vapor deposition.

[0057] Example 1

[0058] Fabrication of a two-dimensional DJ-phase perovskite BDA(FA)Pb2I7 photovoltaic device with n=2

[0059] The device fabrication process includes the following steps:

[0060] Step 1: Prepare a dense titanium dioxide electron transport layer and perform surface coating treatment on the electron transport layer:

[0061] Take 2 ml of titanium tetrachloride (GR, 95%) and 100 ml of deionized water. Under cold bath conditions, add titanium tetrachloride dropwise into the deionized water at a rate of 20 μl / s to prepare a titanium tetrachloride aqueous solution with a volume ratio of 1:50. After standing overnight, place an FTO glass (2 cm * 2 cm) in the titanium tetrachloride aqueous solution and grow it in an oven at 70 °C for 2.5 h. Titanium dioxide in the aqueous solution is deposited on the substrate. After growth, wash with deionized water and ethanol in sequence and blow dry to complete the preparation of the electron transport layer. The thickness of the prepared titanium dioxide electron transport layer is 80 nm.

[0062] 2 mg of KCl was dissolved in 1 ml of isopropanol and spin-coated onto the electron transport layer at 2000 rpm / 4 s + 3000 rpm / 30 s. The electron transport layer was then uniformly annealed at 100 °C for 10 min to complete the modification of the electron transport layer. The thickness of the KCl layer was 5 nm.

[0063] Step 2: Preparation of a two-dimensional perovskite active layer:

[0064] 0.4610 g (1.0 mmol) of PbI₂, 0.1720 g (0.5 mmol) of BDADI(NH₃(CH₂)₄NH₃I₂), and 0.0860 g (0.5 mmol) of FAI(HC(NH₂)₂I) were dissolved in 1 mL of a mixed solution of DMF and NMP, and 0.0202 g (0.30 mmol) of methylammonium chloride (MACl) was added as an additive. The volume ratio of DMF to DMSO was 1:9. This was used to prepare PbI₂. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0065] Using a spin coating machine (KW-4A benchtop spin coater), a 4cm² area FTO substrate was coated. 2 The precursor solution was deposited on the spin coating equipment. The spin coating equipment was operated at a speed of 4000 rpm for 10 s, and the volume of perovskite precursor coated per spin was 50 μl. The temperature was controlled at 22℃ and the humidity at 40% during the spin coating process.

[0066] A low-pressure treatment was performed on the perovskite film deposited on the substrate using a low-pressure auxiliary device (DL-10A quartz vacuum gauge and vacuum pump), followed by annealing using a constant-temperature heating device (heating stage) to obtain a high-quality DJ phase perovskite film. The vacuum level of the low-pressure auxiliary device was 10 Pa, the low-pressure treatment time was 60 s, the annealing temperature of the heating stage was 150 °C, and the annealing time was 20 min, resulting in a perovskite layer with a thickness of 700 nm and a target composition of BDA(FA)Pb₂I₇.

[0067] Step 3: Preparation of a two-dimensional perovskite modification layer:

[0068] 5 mg of OAI was dissolved in 1 ml of isopropanol and spin-coated onto a perovskite film at 3000 rpm for 30 s. The film was then annealed at 100 °C for 10 min to obtain a two-dimensional perovskite modified layer with a thickness of 20 nm.

[0069] The chemical formula for the two-dimensional perovskite modified layer is [M2(FA)]. a-1 Pb a I 3a+1 ] x [N((FA) b- 1Pb b I 3b+1 ] 1-x Where a and b take values ​​from 1 to 3, and x takes values ​​from 0 to 1;

[0070] The M mentioned is OA + N is BDAD 2+ ;

[0071] X-ray diffraction analysis was performed on the perovskite thin film prepared in Example 1. The results of the X-ray diffraction are as follows: Figure 2 As shown in the figure, comparison with the standard spectrum reveals that the prepared film exhibits a characteristic diffraction peak of two-dimensional perovskite at 4.7°. A slight blue shift is also observed in the two-dimensional perovskite film. This is attributed to the fact that some of the added chloride ions did not completely volatilize during annealing, partially replacing iodine ions in the crystal lattice. Simultaneously, a mixed-phase low-dimensional two-dimensional perovskite was formed on the surface of the perovskite, resulting in a slight change in its crystal structure and the formation of a unique two-dimensional perovskite [OA2(FA)]. a-1 Pb a I 3a+1 ] x [BDA((FA) b-1 Pb b I 3b+1 ] 1-x This indicates that the perovskite film treated with halide amine salts formed a heterojunction. Ion migration present in the two-dimensional perovskite leads to I- enrichment on the perovskite surface. - , while I - Defects on the surface of perovskite films exacerbate nonradiative recombination in devices, leading to reduced photoelectric conversion efficiency and stability. However, spin-coating long-chain halide amine salts (OAI) improves the performance of OA... + Cations participate in the formation of heterojunctions through in-situ reactions, consuming excess I- on the perovskite film surface during the process, thereby reducing surface defects and achieving passivation of these defects; simultaneously, the target two-dimensional perovskite component A (FA) is also present. n-1 Pb n I 3n+1 with [OA2(FA) a-1 Pb a I 3a+1 ] x [BDA((FA) b-1 Pb b I 3b+1 ] 1-x As semiconductors, the differences in their physical properties create a built-in electric field at the interface, which promotes the separation of charge carriers and enables efficient transport of charge carriers.

[0072] Step 4: Fabrication of the hole transport layer and counter electrode:

[0073] The Spiro-OMeTAD hole transport layer precursor solution was prepared by adding 72.3 mg Spiro as solute, 17.5 μl of lithium salt (Li-TSFL, 520 mg / ml dissolved in acetonitrile), 28.8 μl of 4-tert-butylpyridine, and 1 ml of chlorobenzene sequentially. The Spiro-OMeTAD precursor solution was spin-coated at 4000 rpm for 30 s to complete the preparation of the hole transport layer, resulting in a hole transport layer with a thickness of 200 nm.

[0074] An 80nm Au metal electrode was deposited using a thermal evaporation apparatus, with an electrode area of ​​0.1cm². 2 The spacing between adjacent metal electrodes is 2 mm.

[0075] Example 2.

[0076] Two-dimensional DJ-phase perovskite BDA(FA)2Pb3I with n=3 10 Fabrication of photovoltaic devices

[0077] The other steps are the same as in Example 1, except that the solutes in the perovskite precursor are 0.4610 g (1.0 mmol) of PbI2, 0.1135 g (0.33 mmol) of BDADI (NH3(CH2)4NH3I2), and 0.1152 g (0.67 mmol) of FAI (HC(NH2)2I), which are dissolved in 1 ml of a mixed solution of DMF and NMP, and 0.0250 g (0.37 mmol) of methylammonium chloride (MACl) is added as an additive. The volume ratio of DMF to DMSO is 1:9. This process is used to prepare PbI2. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0078] Example 3.

[0079] Two-dimensional DJ-phase perovskite BDA(FA)3Pb4I with n=4 13 Fabrication of photovoltaic devices

[0080] The other steps are the same as in Example 1, except that the solutes in the perovskite precursor are 0.4610 g (1.0 mmol) of PbI2, 0.0860 g (0.25 mmol) of BDADI (NH3(CH2)4NH3I2), and 0.1290 g (0.75 mmol) of FAI (HC(NH2)2I), which are dissolved in 1 ml of a mixed solution of DMF and NMP, and 0.0250 g (0.37 mmol) of methylammonium chloride (MACl) is added as an additive. The volume ratio of DMF to DMSO is 1:9. This process is used to prepare PbI2. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0081] Example 4.

[0082] Two-dimensional DJ-phase perovskite BDA(FA)4Pb5I with n=5 16 Fabrication of photovoltaic devices

[0083] The other steps are the same as in Example 1, except that the solutes in the perovskite precursor are 0.4610 g (1.0 mmol) of PbI2, 0.0688 g (0.2 mmol) of BDADI (NH3(CH2)4NH3I2), and 0.1376 g (0.8 mmol) of FAI (HC(NH2)2I), which are dissolved in 1 ml of a mixed solution of DMF and NMP, and 0.0250 g (0.37 mmol) of methylammonium chloride (MACl) is added as an additive. The volume ratio of DMF to DMSO is 1:9. This process is used to prepare PbI2. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0084] Example 5.

[0085] Two-dimensional DJ-phase perovskite BDA(FA)5Pb6I with n=6 19 Fabrication of photovoltaic devices

[0086] The other steps are the same as in Example 1, except that the solutes in the perovskite precursor are 0.4610 g (1.0 mmol) of PbI2, 0.0574 g (0.167 mmol) of BDADI (NH3(CH2)4NH3I2), and 0.1432 g (0.833 mmol) of FAI (HC(NH2)2I), which are dissolved in 1 ml of a mixed solution of DMF and NMP. 0.0250 g (0.37 mmol) of methylammonium chloride (MACl) is added as an additive. The volume ratio of DMF to DMSO is 1:9. This process is used to prepare PbI2. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0087] Example 6.

[0088] Two-dimensional DJ-phase perovskite BDA(FA)6Pb7I with n=7 22 Fabrication of photovoltaic devices

[0089] The other steps are the same as in Example 1, except that the solutes in the perovskite precursor are 0.4610 g (1.0 mmol) of PbI2, 0.0491 g (0.143 mmol) of BDADI (NH3(CH2)4NH3I2), and 0.1474 g (0.857 mmol) of FAI (HC(NH2)2I), which are dissolved in 1 ml of a mixed solution of DMF and NMP. 0.0250 g (0.37 mmol) of methylammonium chloride (MACl) is added as an additive. The volume ratio of DMF to DMSO is 1:9. This process is used to prepare PbI2. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0090] Example 7.

[0091] Two-dimensional DJ-phase perovskite BDA(FA)7Pb8I with n=8 25 Fabrication of photovoltaic devices

[0092] The other steps are the same as in Example 1, except that the solutes in the perovskite precursor are 0.4610 g (1.0 mmol) of PbI2, 0.0430 g (0.125 mmol) of BDADI (NH3(CH2)4NH3I2), and 0.1505 g (0.875 mmol) of FAI (HC(NH2)2I), which are dissolved in 1 ml of a mixed solution of DMF and NMP. 0.0250 g (0.37 mmol) of methylammonium chloride (MACl) is added as an additive. The volume ratio of DMF to DMSO is 1:9. This process is used to prepare PbI2. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0093] Example 8.

[0094] Two-dimensional DJ-phase perovskite BDA(FA)8Pb9I with n=9 28 Fabrication of photovoltaic devices

[0095] The other steps are the same as in Example 1, except that the solutes in the perovskite precursor are 0.4610 g (1.0 mmol) of PbI2, 0.0382 g (0.111 mmol) of BDADI (NH3(CH2)4NH3I2), and 0.1529 g (0.889 mmol) of FAI (HC(NH2)2I), which are dissolved in 1 ml of a mixed solution of DMF and NMP. 0.0250 g (0.37 mmol) of methylammonium chloride (MACl) is added as an additive. The volume ratio of DMF to DMSO is 1:9. This process is used to prepare PbI2. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0096] Example 9.

[0097] Two-dimensional DJ-phase perovskite BDA(FA)9Pb with n=10 10 I 31 Fabrication of photovoltaic devices

[0098] The other steps are the same as in Example 1, except that the solutes in the perovskite precursor are 0.4610 g (1.0 mmol) of PbI2, 0.0382 g (0.111 mmol) of BDADI (NH3(CH2)4NH3I2), and 0.1529 g (0.889 mmol) of FAI (HC(NH2)2I), which are dissolved in 1 ml of a mixed solution of DMF and NMP. 0.0250 g (0.37 mmol) of methylammonium chloride (MACl) is added as an additive. The volume ratio of DMF to DMSO is 1:9. This process is used to prepare PbI2. 2+ A perovskite precursor solution with a concentration of 1 mol / L.

[0099] Example 10.

[0100] Two-dimensional DJ-phase perovskite BDA(FA)4Pb5I with inverted n=5 16 Fabrication of photovoltaic devices

[0101] Step 1: Spin-coat a PEDOT-PSS solution (PEDOT-PSS: water = 1:3) onto an FTO conductive glass substrate to prepare a hole transport layer.

[0102] The spin coating speed is 3000 rpm, the spin coating time is 30 s, and the annealing time is 10 min.

[0103] Step 2: Spin-coating the target component BDA(FA)4Pb5I onto the surface of the hole transport layer using a spin coater. 16 The two-dimensional perovskite precursor solution, with the same composition as in Example 4, was subjected to low-pressure treatment followed by annealing to obtain a two-dimensional perovskite layer; the perovskite precursor solution contained Pb 2+ The concentration is 1 mol / L.

[0104] The solvent for the two-dimensional perovskite is dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a ratio of 1:9 (volume ratio, DMF:DMSO).

[0105] The spin coating speed is 4000 rpm / s, the spin coating time is 10s, and the annealing time is 150℃.

[0106] The vacuum degree of the two-dimensional perovskite low-pressure auxiliary equipment is 10 Pa, and the processing time is 60 s; the annealing temperature is 150 ℃, and the annealing time is 20 min.

[0107] Step 3: Spin-coat a halide amine salt solution onto the surface of the two-dimensional perovskite layer to obtain a two-dimensional perovskite modified layer.

[0108] The concentration of the halide amine salt solution is 5 mg / ml, the solute is OAI, and the solvent is isopropanol.

[0109] The spin coating speed is 4000 rpm / s, the spin coating time is 30s, the annealing temperature is 100℃, and the annealing time is 15min; when the annealing time is 0, it means that no annealing step is performed.

[0110] Step 4: Spin-coat the PCBM electron transport layer precursor solution onto the surface of the two-dimensional perovskite modified layer, and then spin-coat the passivation agent solution for interface treatment to prepare the electron transport layer.

[0111] The concentration of the electron transport layer precursor solution is 20 mg / ml, and the solvent is chlorobenzene.

[0112] The spin coating speed is 1500 rpm and the spin coating time is 30 s.

[0113] The passivating agent is polyazide propane (PEI), the concentration of the passivating agent solution is 0.5 mg / ml, and the solvent is isopropanol;

[0114] Step 5: Deposit silver metal electrodes onto the surface of the electron transport layer by vapor deposition.

[0115] Comparative Example 1.

[0116] The other steps are the same as in Example 4, except that long-chain halide amine salts are not spin-coated onto the surface of the target two-dimensional perovskite to treat the perovskite surface. The device prepared is named n=5 control.

[0117] The current density-voltage (JV) curve was obtained under simulated AM 1.5G solar irradiation at 100 mW / cm². 2 The study was conducted using a Keithley 2400 semiconductor characterization system and a standard xenon lamp solar simulator (EASISOLAP-503A, CROWNTECH, INC.). The transmittance spectrum of the perovskite thin film was collected in the range of 450–900 nm using a Shimadzu UV-1900 spectrophotometer. Indoor light was provided by an indoor light source, and the intensity of the indoor light was corrected using a standard silicon cell. The photoelectric parameters were measured using the Keithley 2400 semiconductor characterization system.

[0118] The test results of the perovskite devices prepared in Examples 2-4 under low-light conditions indoors are as follows: Figure 3As shown in the figure, the fabricated perovskite device exhibits high photoelectric conversion efficiency under low-light conditions. Table 1 presents the test data for various parameters of the two-dimensional perovskite devices with n=3–5 under low-light conditions. The open-circuit voltages of the two-dimensional perovskite devices with n=3, 4, and 5 are 0.97V, 1.0V, and 1.05V, respectively, under low-light conditions. This high voltage provides a foundation for realizing diverse electronic devices. The improvement in various photoelectric parameters is attributed to the reduction of thin-film defects. The photoelectric performance of the device under standard illumination intensity is also improved. Figure 4 Table 2 shows the JV curves of the fabricated optoelectronic devices under standard illumination, and the various optoelectronic parameters are summarized in Table 2. As can be seen from the figure, the successfully fabricated perovskite solar cells based on halide amine salt treatment exhibit excellent optoelectronic performance. The photoelectric conversion efficiency of perovskite optoelectronic devices with various n values ​​has been significantly improved, especially the two-dimensional perovskite device with n=5, whose photoelectric conversion efficiency under standard illumination has exceeded 22%, achieving excellent optoelectronic performance under different illumination intensities.

[0119] Meanwhile, the fabricated low-dimensional perovskite device exhibits semi-transparency and excellent light transmission properties. Figure 5 The transmittance curves of the perovskite thin film are shown. It exhibits selective absorption of visible light up to 650 nm and extremely high transmittance for higher wavelengths, a characteristic that has wide applications in semi-transparent photovoltaic devices. Its IV curve under standard illumination of 1.5 AM is shown below. Figure 7 As shown, under standard illumination, its photoelectric conversion efficiency has reached 10.42%, which is a significant breakthrough for semi-transparent perovskite optoelectronic devices. Simultaneously, its open-circuit voltage, short-circuit current, and fill factor have reached 1.18V, 14.38mA / cm², and 14.38mA / cm², respectively. 2 The halide amine salt effectively promotes the extraction and separation of charge carriers and passivates the surface defects of the thin film after treating the perovskite surface. All photoelectric parameters are greatly improved. Perovskite devices that combine semi-transparency and high photoelectric conversion efficiency can be applied to semi-transparent photovoltaic glass, photovoltaic smart windows, etc.

[0120] The prepared unencapsulated sample was placed in an air environment, and the device stability was tested at regular intervals. The test results are as follows: Figure 7 As shown in the figure, the perovskite device prepared by the experiment can still maintain 99% of its initial efficiency after being placed in air (temperature 25±5℃, humidity 45±10%) for more than 50 days, while the control device only retains 80% of its initial efficiency. This proves that the perovskite device based on halide amine salt treatment plays a beneficial role in improving the stability of the device.

[0121] As can be seen, this invention, through the adjustment of the precursor solution composition and the preparation of the heterojunction, adds MACl as an additive to the precursor solution to delay crystallization and reduce grain boundary defects. Combined with low-pressure assisted and annealing-assisted solvent methods to control the annealing temperature and time, the solvent can be uniformly evaporated during the crystallization process, producing dense, large-sized grains. The two-dimensional perovskite modification layer prepared through in-situ reaction can increase the built-in electric field of the perovskite layer, promote carrier extraction and separation, and passivate thin film surface defects. Ultimately, a perovskite solar cell with excellent photoelectric performance is prepared, exhibiting both good crystallinity and excellent stability. The perovskite device obtained by this invention can be widely used in photovoltaic devices (including indoor and outdoor photovoltaics), semi-transparent photovoltaic glass, photovoltaic smart windows, flexible thin-film devices, etc., and has broad application prospects.

[0122] Table 1 shows the photoelectric parameters of the perovskite devices in embodiments 2 to 4 under indoor light.

[0123]

[0124] Table 2 shows the photoelectric parameters of the perovskite devices in Implementations 2-4 under standard illumination.

[0125]

[0126] In summary, the method for preparing photovoltaic devices based on halide amine salt treatment proposed in this invention is not only simple, easy to implement, and low in cost, but also capable of large-scale production. Furthermore, it yields high-quality, high-performance electronic devices that can be widely used in indoor photovoltaic devices, semi-transparent photovoltaic glass, photovoltaic smart windows, flexible thin-film devices, etc., providing an effective method for the large-scale industrial production of high-performance perovskite optoelectronic devices.

[0127] Matters not covered in this invention are common knowledge.

Claims

1. A photovoltaic device based on halide amine salt treatment, characterized in that: The photovoltaic device can be either a forward-mounted device or an inverted device. In the forward-mounted device, the components from bottom to top are a transparent conductive substrate, an electron transport layer, a two-dimensional perovskite active layer, a two-dimensional perovskite modification layer, a hole transport layer, and a counter electrode. In the inverted device, the components from bottom to top are a transparent conductive substrate, a hole transport layer, a two-dimensional perovskite active layer, a two-dimensional perovskite modification layer, an electron transport layer, and a counter electrode. The general structural formula of the two-dimensional perovskite active layer is A(FA). n-1 Pb n I 3n+1 n values ​​range from 1 to 20, where A is a +2 valence halide cation, FA + It is a formamidinium cation; its thickness is 100~1000 nm; The +2 valence state halide cation mentioned is specifically butanediamine ion (BDA). 2+ Hexamethylenediamine ions (HDA) 2+ ) or propylenediamine ions (PDA) 2+ ); The general structural formula of the two-dimensional perovskite modified layer material is [M2(FA)]. a-1 Pb a I 3a+1 ] x [N((FA) b-1 Pb b I 3b+1 ] 1-x Where a and b take values ​​from 1 to 3, x = 0 to 1, and x is not equal to 0 or 1; M is OA. + N is BDA 2+ HDA 2+ or PDA 2+ The thickness is 1~20 nm.

2. The photovoltaic device based on halide amine salt treatment as described in claim 1, characterized in that: The transparent conductive substrate is one of the following: fluorine-doped SnO2 conductive glass (FTO), indium tin oxide transparent conductive film glass (ITO), PET / ITO (PET is polyethylene terephthalate), and PEN / ITO (PEN is polyethylene naphthalate). The electron transport layer is at least one of titanium dioxide (TiO2), TiO2-SnO2, tin dioxide (SnO2), chlorine-doped titanium dioxide, ZnO-TiO2, and ZnO-SnO2. The electron transport layer of the inverting device is methyl [6,6]-phenyl C61-butyrate (PCBM) or 60(C 60 At least one of nano zinc oxide (ZnO); with a thickness of 5~200 nm; The hole transport layer of the upright device is one of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), or copper cyanide (CuPc); the hole transport layer of the inverted device is poly-3-hexylthiophene (P3HT) or nickel oxide (NiO). x At least one of poly(2,3-dihydrothiopheno-1,4-dioxin)-poly(styrene sulfonate) (PEDOT:PSS); with a thickness of 30~500 nm; The electrode is one or more of carbon, gold, and silver; the electrode of the inverted device is one or more of chromium, copper, and silver; when the electrode is metal, the thickness is 50~120 nm, and when the electrode is carbon, the thickness is 5~30 μm.

3. The method for fabricating a photovoltaic device based on halide amine salt treatment as described in claim 1, characterized in that: One of the following two methods Method 1, the fabrication method of the upright device, includes the following steps: Step 1: Spin-coat an electron transport layer precursor solution onto a conductive glass substrate, and then spin-coat a passivation agent solution for interface treatment to prepare the electron transport layer; The electron transport layer precursor solution is an aqueous solution of titanium tetrachloride with a volume percentage concentration of 0.01~1. The solute of the passivating agent is one or both of potassium chloride and cesium chloride; the concentration is 0.1~5 mg / ml; Step 2: Spin-coat the target component A (FA) onto the surface of the electron transport layer using a spin coater. n-1 Pb n I 3n+1 A two-dimensional perovskite precursor solution was subjected to low-pressure treatment followed by annealing to obtain a two-dimensional perovskite layer; the perovskite precursor solution contained Pb 2+ The concentration is 0.2~2 mol / L; The spin coating speed is 1000~10000 rpm / s, and the spin coating time is 1~20 s; The solvent for the two-dimensional perovskite includes at least one of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and dimethylacetamide (DMAc); The vacuum degree of the two-dimensional perovskite low-pressure auxiliary equipment is 1~100 Pa and the processing time is 1~120 s; the annealing temperature is 50~200℃ and the annealing time is 1~60 min. Step 3: Spin-coat a halide amine salt solution onto the surface of the two-dimensional perovskite layer to obtain a two-dimensional perovskite modified layer; The concentration of the halide amine salt solution is 0.1~20 mg / ml, the solute is OAI, and the solvent is isopropanol; The spin coating speed is 1000~10000 rpm / s, the spin coating time is 10~60 s, the annealing temperature is 25~150℃, and the annealing time is 0~30 min; when the annealing time is 0, it means that no annealing step is performed. Step 4: Spin-coat the hole transport layer precursor solution onto the surface of the two-dimensional perovskite modified layer to prepare the hole transport layer; Step 5: Deposit a counter electrode on the surface of the hole transport layer by vapor deposition. Alternatively, method two, the fabrication method of the inverted device, includes the following steps: Step 1: Spin-coat the hole transport layer precursor solution onto a conductive glass substrate to prepare the hole transport layer; Step 2: Spin-coat the target component A (FA) onto the surface of the hole transport layer using a spin coater. n-1 Pb n I 3n+1 A two-dimensional perovskite precursor solution was subjected to low-pressure treatment followed by annealing to obtain a two-dimensional perovskite layer; the perovskite precursor solution contained Pb 2+ The concentration is 0.2~2 mol / L; The spin coating speed is 1000~10000 rpm / s, and the spin coating time is 1~20 s; The solvent for the two-dimensional perovskite includes at least one of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and dimethylacetamide (DMAc); The vacuum degree of the two-dimensional perovskite low-pressure auxiliary equipment is 1~100 Pa and the processing time is 1~120 s; the annealing temperature is 50~200℃ and the annealing time is 1~60 min. Step 3: Spin-coat a halide amine salt solution onto the surface of the two-dimensional perovskite layer to obtain a two-dimensional perovskite modified layer; The concentration of the halide amine salt solution is 0.1~20 mg / ml, the solute is OAI, and the solvent is isopropanol; The spin coating speed is 1000~10000 rpm / s, the spin coating time is 10~60 s, the annealing temperature is 25~150℃, and the annealing time is 0~30 min; when the annealing time is 0, it means that no annealing step is performed. Step 4: Spin-coat the electron transport layer precursor solution onto the surface of the two-dimensional perovskite modified layer, and then spin-coat the passivation agent solution for interface treatment to prepare the electron transport layer; The concentration of the electron transport layer precursor solution is 1~50 mg / ml, and the solvent is chlorobenzene; The passivating agent is at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and polyethyleneimine (PEI); the concentration of the passivating agent solution is 0.1~5 mg / ml, and the solvent is isopropanol; Step 5: Deposit the counter electrode on the surface of the electron transport layer by vapor deposition.

4. The photovoltaic device based on halide amine salt treatment as described in claim 1, characterized in that it is applied to perovskite cells, semi-transparent photovoltaic glass, photovoltaic smart windows, or flexible thin films.

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