A tin-based perovskite thin film, a preparation method thereof and a device

Abstract

The application discloses a tin-based perovskite film, a preparation method thereof and a device, and the structural general formula of the tin-based perovskite is ABX3-C x B y X z , wherein A is an organic or inorganic cation capable of forming a three-dimensional perovskite; B is a Sn 2+ or Sn 2+ / Pb 2+ mixed cation; C is an organic cation capable of forming a low-dimensional perovskite; X is a halogen anion; and x:y:z=0-4:0-1:0-6. The application adopts a solution method, and recrystallization or secondary growth occurs in the in-situ crystallization process of the film under the condition that a solvent atmosphere exists, so that the crystallinity of the film is improved, the defect state density of the film is reduced, the fluorescent quantum efficiency is improved, and finally the efficiency and stability of the tin-based perovskite optoelectronic device are improved.

Description

Technical fields:

[0001] This invention relates to tin-based metal halide materials, and more particularly to the influence of solvent atmosphere on the performance of tin-based perovskite thin films and devices during film formation. Background technology:

[0002] Organic-inorganic hybrid perovskite materials possess advantages such as high absorption coefficient, high mobility, tunable bandgap, high color purity, high fluorescence quantum efficiency, and simple fabrication process, showing broad application prospects in optoelectronic fields such as solar cells, light-emitting diodes (LEDs), and detectors (Nat. Nanotechnol. 2014, 9, 687). In recent years, the performance of lead-based perovskite-based LEDs has improved rapidly, with external quantum efficiencies exceeding 20% ​​(Nat. Photonics 2016, 10, 699). However, the toxicity of lead severely restricts the application prospects of perovskite optoelectronic devices. Among many non-lead perovskite materials, tin-based perovskites have similar structures and optoelectronic properties to lead-based perovskites, making them one of the ideal materials for realizing environmentally friendly perovskite light-emitting devices (J. Phys. Chem. Lett. 2019, 10, 453). Currently, although tin-based perovskites have been used to create light-emitting devices, their rapid crystallization and easy oxidation lead to high defect density and low fluorescence quantum efficiency, limiting further improvements in device performance (Adv. Mater. 2016, 28, 8029; Adv. Mater. 2021, 2104414). Therefore, it is urgent to innovate the preparation methods of tin-based perovskite thin films to improve film quality and device performance. Summary of the Invention

[0003] The technical problem this invention aims to solve is to address the shortcomings of existing tin-based perovskite thin film crystallization technologies by providing a novel preparation method. By modifying the perovskite material composition and the solvent atmosphere during film preparation, the crystallinity of the film is improved, the defect state density is reduced, and the fluorescence quantum efficiency is increased, thereby enhancing the efficiency and stability of tin-based perovskite optoelectronic devices.

[0004] A tin-based perovskite thin film is prepared by first dissolving AX, BX2, and CX in a solvent to obtain a precursor solution. With or without functional additives, the film is prepared by recrystallization or secondary growth during in-situ crystallization in the presence of a solvent atmosphere using a solution method. The general structural formula of the tin-based perovskite thin film is ABX3-C. x B y X z Where A is an organic or inorganic cation capable of forming three-dimensional perovskites; B is Sn 2+ Cations or Sn 2+ / Pb 2+Mixed metal cations; C is an organic cation capable of forming low-dimensional perovskites; X is a halide anion; x:y:z = 0-4:0-1:0-6.

[0005] Preferred solvents include methanol, ethanol, isopropanol, dimethoxyethanol, acetone, formamide, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetramethylene sulfoxide (THTO), 1,3-dimethylpropaneurea (DMPU), γ-butyrolactone (GBL), N-alkylpyrrolidone (NMP), acetonitrile, methylamine acetate, or any mixture thereof in any proportion.

[0006] Solution-based methods include spin coating, blade coating, inkjet printing, and screen printing. During film formation, the ratio of the partial pressure of vapor generated by the solvent atmosphere to the total ambient pressure is 0-0.5:1.

[0007] The preferred solvent is a mixture of DMF and DMSO, the more preferred solvent is a mixture of DMF and DMSO with a volume ratio of 1:4 to 4:1, and the most preferred solvent is a mixture of DMF and DMSO with a volume ratio of 1:4.

[0008] The solvent atmosphere can slow down the crystallization rate of tin-based perovskite and reduce defect states during film formation, thereby improving the crystallization quality of the thin film. The principle is that during spin coating, the solvent atmosphere inhibits the evaporation of solvent in the precursor solution and dissolves crystal nuclei or small grains formed in the early stages of crystallization, thus inhibiting the continued growth of crystal nuclei. As spin coating progresses, the solvent in the precursor solution further evaporates, allowing some of the crystal nuclei dissolved by the solvent atmosphere to re-participate in crystallization growth, i.e., in-situ recrystallization or secondary growth.

[0009] The organic ammonium salt capable of forming a low-dimensional perovskite structure is one or more of the following: alkyl ammonium salts (preferably ethylammonium salt, butylammonium salt, tetramethylammonium salt, tetrabutylammonium salt, piperazine dihydrogen ammonium salt), aromatic ammonium salts (benzoylammonium salt, phenylethylammonium salt, phenylpropylammonium salt, phenylbutylammonium salt, isophthalic acid dimethylammonium salt, terephthalic acid dimethylammonium salt, terephthalic acid diethylammonium salt, pentafluorophenylethylammonium salt, benzimidazole salt, phenethylhydrazine ammonium salt, thiophene ethylammonium salt), and guanidine salts (preferably halogenated guanidine salts, aminohalogenated guanidine salts); the organic phosphorus salt capable of forming a low-dimensional perovskite structure is one or more of the following: tetraethyl phosphorus halide, tetrabutyl phosphorus halide, and tetraphenyl phosphorus halide. This is to improve film-forming properties and stability. Phenylacetium salt is preferred, and the phenylethylammonium salt is phenylethylammonium iodide.

[0010] The halide anion is I – ,Br – Cl – F - One or a mixture thereof in any proportion, preferably with halogen anion I – F -Mixture; the organic or inorganic cation A capable of forming a three-dimensional structure is Cs. + 、Rb + K + Na + FA + MA + One or a mixture thereof in any proportion, preferably FA + MA + 、Rb + Cs + One or a mixture thereof in any proportion. The preferred metal cation is Sn. 2+ Cations or Sn 2+ / Pb 2+ Mixed metal cations.

[0011] The selected solvent atmosphere and functional additives will not alter the tin-based perovskite ABX3-C. x B y X z Its chemical composition.

[0012] Functional additives are acids and their salts, amines and their salts, and amino acid-based organic compounds that interact with precursor components to slow down perovskite crystallization and reduce defect state density. These functional additives are acids and their salts (preferably p-chlorobenzoic acid, 3-chlorobenzoic acid, 2-naphthoic acid, 1-methyl-2-pyrrolic acid, 2-pyrrolic acid, valeric acid, butyric acid, taurine, 2-aminoethanesulfonic acid, 4-bromobenzoic acid, glutaric acid, hexanoic acid, propylphosphonic acid, octanoic acid, isonicotinic acid, citric acid, tetrafluoroboric acid, oxalic acid, benzoic acid, hypophosphoric acid, butylboric acid, benzenesulfonic acid, etc.). Acids, sodium oxalate, potassium oxalate, citric acid, sodium citrate, potassium citrate, benzotricarboxylic acid, sodium benzotricarboxylate), amines and their salts (preferably 1,5-dimethylhexylamine, dimethylamine, 1,8-octanediamine, m-toluidine, n-butylamine, 1,4-phenylenediamine, octylamine, 1,3-propanediamine, 3-methylaminopropylamine, N-benzylethylenediamine, cyclohexylmethylamine, 5-aminopyrimidine, 9-aminoanthracene, 3-dimethylaminopropylamine, bicyclohexylmethyl ... Hexylcarbodiimide, N,N-dimethylethylenediamine, 1,6-hexanediamine, tert-octylamine, aniline, ethylamine, cyclooctylamine, phenylhydrazine hydrochloride), and one or more amino acids (preferably tryptophan, phenylalanine, aminosulfonic acid, 7-aminoheptanoic acid, glycine, 3-aminopropane-1-phosphate, aminomethanesulfonic acid, glycine, 2-aminomethylphenylacetic acid, 3-(aminosulfonyl)propionic acid, N-acetyl-L-cysteine, 3-amino-4-hydroxybenzenesulfonic acid, 4-aminobutane-1-phosphate, p-aminobenzoic acid, 6-aminohexanoic acid, EDTA, 3-aminopropanesulfonic acid, 2-amino-4-sulfonylbutyric acid, 2-aminoethanol hydrogen sulfate, N-(2-acetamino)-3-aminoethanesulfonic acid, γ-aminobutyric acid, 5-aminovaleric acid, lysine, alanine, tryptophan, 5-hydroxytryptophan, cysteine). The most preferred additive that interacts with the precursor component is one or more of the following: phenylhydrazine hydrochloride, 5-aminovaleric acid, alanine, tryptophan, cysteine, citric acid, and tribenzoic acid. A preferred structural formula is shown below:

[0013]

[0014] The aforementioned additives can form weak interactions with perovskite precursor components, or simultaneously possess a certain degree of reducing properties. By partially reducing tetravalent tin impurities in the precursor solution to divalent tin, the density of defect states in the thin film is reduced. The additives do not alter the original composition of the tin-based perovskite.

[0015] In the preferred precursor solution, the molar ratio of each component is AX:BX2:CX:additive = 0.5-4:1:0-2:0-0.8; the total mass fraction of the precursor in the solution is 5%-70%.

[0016] The preparation method of the above-mentioned tin-based perovskite thin film includes the following steps: first, AX, BX2, and CX are dissolved in a solvent to obtain a precursor solution; with or without the addition of functional additives, the film is recrystallized or secondary grown in situ during the in-situ crystallization process in the presence of a solvent atmosphere using a solution method to obtain the tin-based perovskite thin film; the general structural formula of the tin-based perovskite thin film is ABX3-C. x B y X z Where A is an organic or inorganic cation capable of forming three-dimensional perovskites; B is Sn 2+ Cations or Sn 2+ / Pb 2+ Mixed metal cations; C is an organic cation capable of forming low-dimensional perovskites; X is a halide anion; x:y:z = 0-4:0-1:0-6.

[0017] Optoelectronic devices include light-emitting, photovoltaic, and detector devices. The optoelectronic devices are composed of a substrate, an anode, a hole transport layer, an active layer, an electron transport layer, and a cathode, wherein the active layer can be a tin-based perovskite thin film.

[0018] Therefore, the tin-based perovskite thin film of the present invention can be used in the preparation of active layers for optoelectronic devices, preferably light-emitting, photovoltaic, and detector devices.

[0019] The fabrication of optoelectronic devices can be carried out through the following steps:

[0020] a) The transparent conductive substrate ITO glass was ultrasonically cleaned twice with acetone and ethanol respectively. After treatment, it was dried with nitrogen gas. Then the ITO was transferred to an oxygen plasma cleaner and oxygen plasma cleaned under vacuum conditions.

[0021] b) A PEDOT:PSS hole transport layer was prepared using a solution method and then thermally annealed.

[0022] c) Prepare tin-based perovskite thin film functional layers using a solution method and perform thermal annealing.

[0023] d) The TmPyPB electron transport layer, LiF buffer layer and Al anode layer were deposited sequentially using the thermal evaporation method.

[0024] The advantages of this invention compared with the prior art are as follows:

[0025] 1) Existing tin-based perovskites have a fast crystallization rate and poor film-forming properties. This invention introduces a specific solvent atmosphere during the film-forming process to cause in-situ recrystallization or secondary growth of the film, which effectively slows down the crystal growth rate and improves the crystallization quality of the film.

[0026] 2) In traditional tin-based perovskites, divalent tin is easily oxidized to tetravalent tin. This invention uses organic ammonium salts that can form low-dimensional structures and functional additives with reducing properties to inhibit the oxidation of divalent tin, reduce film defects, and improve film quality and device performance. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the tin-based perovskite light-emitting device structure described in this invention;

[0028] Figure 2 These are the absorption and fluorescence spectra of Example 1 of the present invention; control refers to the thin film under solvent-free atmosphere conditions, and VASC refers to the thin film under solvent atmosphere conditions; the same applies below.

[0029] Figure 3 It is the excitation light intensity-dependent PL QE of Embodiment 1 of the present invention;

[0030] Figure 4 This is the TCSPC spectrum of Example 1 of the present invention;

[0031] Figure 5 This is the spin-coated in-situ PL spectrum of Example 1 of the present invention;

[0032] Figure 6 This is the spin-coated in-situ absorption spectrum of Example 1 of the present invention;

[0033] Figure 7 This is a SEM image of the thin film morphology of Example 1 of the present invention;

[0034] Figure 8 This is an AFM image of the thin film morphology of Example 1 of the present invention;

[0035] Figure 9 This is the X-ray diffraction (XRD) spectrum of Embodiment 1 of the present invention;

[0036] Figure 10 This is a current density-voltage-irradiance relationship diagram of Embodiment 1 of the present invention;

[0037] Figure 11 This is the external quantum efficiency-current density relationship diagram of Embodiment 1 of the present invention;

[0038] Figure 12 It is the excitation light intensity-dependent PLQE of Embodiment 2 of the present invention;

[0039] Figure 13 This is the TCSPC spectrum of Example 2 of the present invention;

[0040] Figure 14This is a SEM image of the thin film morphology of Example 2 of the present invention;

[0041] Figure 15 This is an AFM image of the thin film morphology of Example 2 of the present invention;

[0042] Figure 16 This is XPS data from Embodiment 2 of the present invention.

[0043] Figure 17 This is a current density-voltage-irradiance relationship diagram of Embodiment 2 of the present invention;

[0044] Figure 18 This is the external quantum efficiency-current density relationship diagram of Embodiment 2 of the present invention;

[0045] Figure 19 This is an AFM topography diagram of Embodiment 3 of the present invention;

[0046] Figure 20 This is an AFM topography diagram of Embodiment 4 of the present invention;

[0047] Figure 21 This is the current density-voltage-irradiance relationship diagram of Embodiment 4 of the present invention;

[0048] Figure 22 This is the external quantum efficiency-current density relationship diagram of Embodiment 4 of the present invention;

[0049] Figure 23 This is an AFM topography diagram of Embodiment 5 of the present invention;

[0050] Figure 24 This is the current density-voltage-irradiance relationship diagram of Embodiment 5 of the present invention;

[0051] Figure 25 This is the external quantum efficiency-current density relationship diagram of Embodiment 5 of the present invention;

[0052] Figure 26 This is an AFM topography diagram of Embodiment 6 of the present invention;

[0053] Figure 27 This is the current density-voltage-irradiance relationship diagram of Embodiment 6 of the present invention;

[0054] Figure 28 This is the external quantum efficiency-current density relationship diagram of Embodiment 6 of the present invention;

[0055] Figure 29 This is an AFM topography diagram of Embodiment 7 of the present invention;

[0056] Figure 30This is the current density-voltage-irradiance relationship diagram of Embodiment 7 of the present invention;

[0057] Figure 31 This is the external quantum efficiency-current density relationship diagram of Embodiment 7 of the present invention;

[0058] Figure 32 This is an AFM topography diagram of Embodiment 8 of the present invention;

[0059] Figure 33 This is the current density-voltage-irradiance relationship diagram of Embodiment 8 of the present invention;

[0060] Figure 34 This is the external quantum efficiency-current density relationship diagram of Embodiment 8 of the present invention;

[0061] Figure 35 This is an AFM topography diagram of Embodiment 9 of the present invention;

[0062] Figure 36 This is the current density-voltage-irradiance relationship diagram of Embodiment 9 of the present invention;

[0063] Figure 37 This is the external quantum efficiency-current density relationship diagram of Embodiment 9 of the present invention;

[0064] Figure 38 This is an AFM topography diagram of Embodiment 10 of the present invention;

[0065] Figure 39 This is a current density-voltage-irradiance relationship diagram of Embodiment 10 of the present invention;

[0066] Figure 40 This is the external quantum efficiency-current density relationship diagram of Embodiment 10 of the present invention;

[0067] Figure 41 This is an AFM topography diagram of Embodiment 11 of the present invention;

[0068] Figure 42 This is the current density-voltage-irradiance relationship diagram of Embodiment 11 of the present invention;

[0069] Figure 43 This is the external quantum efficiency-current density relationship diagram of Embodiment 11 of the present invention;

[0070] Figure 44 This is an AFM topography diagram of Embodiment 12 of the present invention;

[0071] Figure 45 This is the current density-voltage-irradiance relationship diagram of Embodiment 12 of the present invention;

[0072] Figure 46 This is the external quantum efficiency-current density relationship diagram of Embodiment 12 of the present invention;

[0073] Figure 47 This is an AFM topography diagram of Embodiment 13 of the present invention;

[0074] Figure 48 This is the current density-voltage-irradiance relationship diagram of Embodiment 13 of the present invention;

[0075] Figure 49 This is the external quantum efficiency-current density relationship diagram of Embodiment 13 of the present invention;

[0076] Figure 50 This is the current density-voltage relationship diagram of Embodiment 14 of the present invention;

[0077] Figure 51 This is the current density-voltage relationship diagram of Embodiment 15 of the present invention. Detailed Implementation

[0078] The present invention will be described in detail below with reference to specific embodiments.

[0079] The device fabrication in the following embodiments includes the following steps:

[0080] a) The transparent conductive substrate ITO glass was ultrasonically cleaned twice using acetone and ethanol respectively, and then dried with nitrogen. The ITO was then transferred to an oxygen plasma cleaner and cleaned under vacuum conditions.

[0081] b) The PEDOT:PSS hole transport layer was prepared by solution method and then thermally annealed.

[0082] c) Prepare tin-based perovskite functional layers using a solution method and then perform thermal annealing.

[0083] d) The TmPyPB electron transport layer, LiF buffer layer and Al anode layer were deposited sequentially using the thermal evaporation method.

[0084] Example 1

[0085] PEAI, FAI, SnI2, and SnF2 were dissolved in a mixed solvent of DMF and DMSO at a molar ratio of 0.2:1:1:0.1 and stirred for 12 hours to prepare a precursor solution with a molar fraction of 7%. The properties of the thin films and device performance were compared under solvent-free conditions. The coating method under solvent-free conditions involved adding 50–400 μL of pure solvent to a spin coater or glove box before proceeding with normal coating operations. The device structure was: glass substrate ITO / PEDOT:PSS / tin-based perovskite / TmPyPB / LiF / Al.

[0086] A tin-based perovskite light-emitting diode includes 1) a transparent conductive glass ITO cathode, 2) a hole transport layer, 3) a light-emitting layer, 4) an electron transport layer, and 5) a buffer layer and an anode layer.

[0087] 1) The substrate is indium tin oxide (ITO) conductive glass, the sheet resistance of the ITO film is 15Ω / □, and the film thickness is 100-200nm.

[0088] 2) The hole transport layer is PEDOT:PSS with a film thickness of 10-100nm.

[0089] 3) The light-emitting layer is a tin-based perovskite with a film thickness of 10-200 nm.

[0090] 4) The electron transport layer is 1,3,5-tris(3-pyridyl-3-phenyl)benzene (TmPyPB) with a film thickness of 10-100 nm.

[0091] 5) The buffer layer and the anode layer are lithium fluoride (LiF) and aluminum (Al), respectively, with film thicknesses of 1.2 nm and 100 nm.

[0092] Following the above device fabrication method, tin-based perovskite LED devices were prepared under solvent-free and solvent-free atmospheres, and the photoelectric properties of the devices were measured in a glove box.

[0093] The structure of the tin-based perovskite light-emitting device in this embodiment is shown below. Figure 1 .

[0094] The absorption and emission spectra of thin films prepared with and without solvent atmospheres are shown in [reference needed]. Figure 2 .like Figure 2 As shown, the absorption edge and emission wavelength of the thin film remain basically unchanged under different conditions, indicating that the solvent atmosphere has little effect on the chemical composition of tin-based perovskite.

[0095] The fluorescence quantum efficiency (PLQE) of the thin film under 445 nm excitation is shown in [reference needed]. Figure 3Compared to the unused atmosphere, the films prepared under the solvent atmosphere had significantly higher PLQE, indicating a lower defect state density and better film quality.

[0096] The transient fluorescence spectrum (TCSPC) of the thin film under 445 nm excitation is shown in the figure. Figure 4 It can be seen that the film PL lifetime increases significantly when a solvent atmosphere is used, indicating fewer film defects, which is consistent with the PLQE data.

[0097] In-situ fluorescence (PL) spectra of tin-based perovskites during spin coating are shown in [Figure number missing]. Figure 5 The excitation wavelength was 445 nm. It can be seen that without a solvent atmosphere, after the antisolvent was added at 30 seconds, the film PL intensity rapidly reached its maximum value and remained high, indicating that crystal growth continued after rapid nucleation. With a solvent atmosphere, after the antisolvent was added at 30 seconds, the film PL intensity first increased, then decreased, and then increased again, indicating that under the action of both the solvent atmosphere and the instantaneous antisolvent, the perovskite successively underwent three processes: instantaneous nucleation, grain dissolution, and recrystallization. In other words, the solvent atmosphere slowed down the crystallization rate of tin-based perovskite.

[0098] The in-situ absorption spectrum of tin-based perovskite during spin coating is shown in the figure. Figure 6 It can be seen that without a solvent atmosphere, after the antisolvent is added at 30 seconds, the film absorption intensity rapidly reaches its maximum value and remains at a high level, consistent with the in-situ PL phenomenon. With a solvent atmosphere, after the antisolvent is added at 30 seconds, the film absorption intensity first increases, then decreases, and then increases again, consistent with the in-situ PL phenomenon, further demonstrating the retarding effect of the solvent atmosphere on the crystallization of tin-based perovskites.

[0099] The scanning electron microscope (SEM) image of the thin film in this embodiment can be found in [link to SEM image]. Figure 7 It can be observed that a dense and completely covered film is obtained without using a solvent atmosphere; while under solvent atmosphere conditions, the film exhibits an uneven shape, and the coverage decreases while the grains become larger.

[0100] The atomic force microscopy (AFM) images and line scan data showing the height variations of the thin film in this embodiment are shown below. Figure 8 As can be seen, the film is relatively flat when no solvent is used; while the uneven film has a height of about 65 nm when a solvent is used.

[0101] The XRD pattern of the thin film in this embodiment is shown below. Figure 9 As can be seen, the diffraction peak intensity of the film is significantly enhanced after using a solvent atmosphere, indicating a significant improvement in the crystallinity of the film.

[0102] The relationship between current density, voltage, and irradiance is shown in the figure. Figure 10It can be seen that when using a solvent atmosphere, the device lights up at 2.0V, while the device without a solvent atmosphere lights up at 2.4V.

[0103] The curve showing the change of external quantum efficiency with current density is shown below. Figure 11 The results show that using spin coating conditions with a solvent atmosphere can improve device efficiency from 2% to 3.4%, mainly due to the improvement in the quality of the perovskite film.

[0104] Example 2

[0105] PEAI, FAI, SnI2, SnF2, and phenylhydrazine hydrochloride (PH) additive were dissolved in a mixed solvent of DMF and DMSO in a molar ratio of 0.2:1:1:0.1:0.1, and stirred for 12 hours to prepare a 7% (w / w) precursor solution. The solution was then coated under solvent atmosphere conditions. The device fabrication method is the same as in Example 1.

[0106] The fluorescence quantum efficiency (PLQE) of the thin film under 445 nm excitation is shown in [reference needed]. Figure 12 It can be seen that the PLQE of the film increases significantly under the action of phenylhydrazine hydrochloride additive, indicating that the defect state density in the perovskite film is greatly reduced during the crystallization process.

[0107] The transient fluorescence spectrum (TCSPC) of the thin film under 445 nm excitation is shown below. Figure 13 It can be seen that the PL lifetime of the film increased significantly after using phenylhydrazine hydrochloride as an additive, indicating fewer defects, which is consistent with the PLQE data.

[0108] SEM images of the VASC+PH film are shown below. Figure 14 By comparing with Example 1 Figure 7 The comparison revealed that the phenylhydrazine hydrochloride additive had no significant effect on the film morphology, but the grain boundary contours were more obvious, indicating that the crystallinity was further improved.

[0109] AFM diagram of VASC+PH film is shown below Figure 15 By comparing with Example 1 Figure 8 The comparison revealed that the phenylhydrazine hydrochloride additive had no significant effect on the film morphology, but the grain boundary contours were more obvious, indicating that the crystallinity was further improved.

[0110] X-ray photoelectron spectroscopy (XPS) data of SnI4 thin films with and without phenylhydrazine hydrochloride doping, along with corresponding precursor solution photographs, are shown below. Figure 16 It can be seen that phenylhydrazine hydrochloride can... 4+ Partially restored to Sn 2+ .

[0111] The relationship between current density, voltage, and irradiance is shown in the figure. Figure 17As can be seen from the figure, the irradiance of the device increases significantly under the influence of phenylhydrazine hydrochloride additive.

[0112] The external quantum efficiency-current density relationship is shown in Figure 18 As shown in the figure, the device efficiency increased from 3.4% to 5.3% under the influence of phenylhydrazine hydrochloride additive. This is mainly due to the phenylhydrazine hydrochloride removing Sn from the precursor solution. 4+ Impurities reduced to Sn 2+ This reduces film defects and improves the PLQE of the film.

[0113] Example 3

[0114] FAI, SnI2, PEAI, and SnF2 were dissolved in a molar ratio of 0.2:1:1:0.1:0.1 in a mixed solvent of DMF and DMSO at different volume ratios (1:0, 4:1, 2:2, 1:4), and stirred for 12 hours to prepare a precursor solution with a mass fraction of 7%. The preparation method of thin films and devices under solvent atmosphere is as described in Example 1.

[0115] The AFM morphology image of the thin film in this embodiment is shown below. Figure 19 It can be seen that under different precursor solvent compositions, the solvent atmosphere can delay the crystallization of perovskite, thereby obtaining films with larger particles.

[0116] Example 4

[0117] FAI, SnI2, PEAI, SnF2, and 5-aminovaleric acid (5AVA) additive were dissolved in a mixed solvent of DMF and DMSO at a molar ratio of 0.2:1:1:0.1:0.1, and stirred for 12 hours to prepare a 7% (w / w) precursor solution. The preparation method for the thin film and device under solvent atmosphere was as described in Example 1. The AFM morphology of the thin film in this example is shown in [reference needed]. Figure 20 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 21 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 22 As can be seen, high device performance can also be achieved using the 5AVA additive.

[0118] Example 5

[0119] FAI, SnI2, PEAI, SnF2, and β-alanine (ALa) additive were dissolved in a mixed solvent of DMF and DMSO at a molar ratio of 0.2:1:1:0.1:0.1, and stirred for 12 hours to prepare a 7% (w / w) precursor solution. The preparation method for the thin film and device under solvent atmosphere was as described in Example 1. The AFM morphology of the thin film in this example is shown in [reference needed]. Figure 23 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 24The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 25 As can be seen, high device performance can also be achieved using ALa additives.

[0120] Example 6

[0121] FAI, SnI2, PEAI, SnF2, and cysteine ​​(CYS) additive were dissolved in a mixed solvent of DMF and DMSO at a molar ratio of 0.2:1:1:0.1:0.1, and stirred for 12 hours to prepare a 7% (w / w) precursor solution. The preparation method for the thin film and device under solvent atmosphere was as described in Example 1. The AFM morphology of the thin film in this example is shown in [example description missing]. Figure 26 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 27 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 28 As can be seen from the figure, high device performance can also be achieved using CYS additives.

[0122] Example 7

[0123] FAI, SnI2, PEAI, SnF2, and citric acid (CA) additives were dissolved in a mixed solvent of DMF and DMSO at a molar ratio of 0.2:1:1:0.1:0.1, and stirred for 12 hours to prepare a 7% (w / w) precursor solution. The preparation method for the thin film and device under solvent atmosphere is as described in Example 1. The AFM morphology of the thin film in this example is shown in [reference needed]. Figure 29 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 30 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 31 As shown in the figure, high device performance can also be achieved using CA additives.

[0124] Example 8

[0125] FAI, SnI2, PEAI, SnF2 and benzoic acid (MSDS) additives were dissolved in a mixed solvent of DMF and DMSO in a molar ratio of 0.2:1:1:0.1:0.1 and stirred for 12 hours to prepare a precursor solution with a mass fraction of 7%.

[0126] The preparation method of the thin film and device under a solvent atmosphere is as described in Example 1. The AFM morphology of the thin film in this example is shown below. Figure 32 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 33 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 34 As shown in the figure, high device performance can also be achieved using MSDS additives.

[0127] Example 9

[0128] PEAI, CsI, FAI, SnI2, SnF2 and phenylhydrazine hydrochloride (PH) additive were dissolved in a mixed solvent of DMF and DMSO in a molar ratio of 0.2:0.1:0.9:1:0.1:0.1, and stirred for 12 hours to prepare a precursor solution with a mass fraction of 7%.

[0129] The preparation method of the thin film and device under a solvent atmosphere is as described in Example 1. The AFM morphology of the thin film in this example is shown below. Figure 35 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 36 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 37 As can be seen from the figure, high device performance can also be achieved using Cs doping.

[0130] Example 10

[0131] TEAI, FAI, SnI2, SnF2 and phenylhydrazine hydrochloride (PH) additives were dissolved in a mixed solvent of DMF and DMSO in a molar ratio of 0.2:1:1:0.1:0.1 and stirred for 12 hours to prepare a precursor solution with a mass fraction of 7%.

[0132] The preparation method of the thin film and device under a solvent atmosphere is as described in Example 1. The AFM morphology of the thin film in this example is shown below. Figure 38 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 39 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 40 As shown in the figure, high device performance can also be achieved by using TEAI doping.

[0133] Example 11

[0134] PEAI, FAI, SnI2, SnBr2, SnF2 and phenylhydrazine hydrochloride (PH) additive were dissolved in a mixed solvent of DMF and DMSO in a molar ratio of 0.2:1:0.9:0.1:0.1:0.1, and stirred for 12 hours to prepare a precursor solution with a mass fraction of 7%.

[0135] The preparation method of the thin film and device under a solvent atmosphere is as described in Example 1. The AFM morphology of the thin film in this example is shown below. Figure 41 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 42 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 43 As can be seen from the figure, high device performance can also be achieved using Br doping.

[0136] Example 12

[0137] PEAI, FAI, SnI2, and SnF2 were dissolved in a mixed solvent of DMF and DMSO at a molar ratio of 0.2:1:1:0.1 and stirred for 12 hours to prepare a precursor solution with a molar fraction of 7%. The properties of the films and device performance were compared under solvent-containing and solvent-free conditions. The coating method under solvent-containing conditions was as follows: 50–400 μL of pure DMF was added to the spin coater or glove box before proceeding with the normal coating operation.

[0138] The device fabrication method under a solvent atmosphere is as described in Example 1. The thin film AFM morphology of this example is shown in [reference needed]. Figure 44 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 45 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 46 As can be seen from the figure, the effect of using DMF as a solvent atmosphere is not obvious.

[0139] Example 13

[0140] FAI, SnI2, and SnF2 were dissolved in a mixed solvent of DMF and DMSO in a molar ratio of 1:1:0.1 and stirred for 12 hours to prepare a precursor solution with a molar fraction of 7%.

[0141] The preparation method of the thin film and device under a solvent atmosphere is as described in Example 1. The AFM morphology of the thin film in this example is shown below. Figure 47 The relationship between current density, voltage, and irradiance is shown in [reference needed]. Figure 48 The external quantum efficiency-current density relationship is shown in [reference needed]. Figure 49 As can be seen from the figure, the effect is worse without using PEAI.

[0142] Example 14

[0143] FAI, SnI2, PEAI, and SnF2 were dissolved in a molar ratio of 0.2:1:1:0.1:0.1 in a mixed solvent of DMF and DMSO at different volume ratios (1:0, 4:1, 2:2, 1:4), and stirred for 12 hours to prepare a 20% (w / w) precursor solution. The precursor solution was spin-coated onto a PTAA substrate under a solvent atmosphere to obtain a tin-based perovskite film. PCBM, MoO3, and Ag electrodes were then deposited to fabricate a solar cell device. Its photovoltaic performance is shown in [Figure / Reference]. Figure 50 .

[0144] Example 15

[0145] FAI, SnI2, PEAI, and SnF2 were dissolved in a molar ratio of 0.2:1:1:0.1:0.1 in a mixed solvent of DMF and DMSO at different volume ratios (1:0, 4:1, 2:2, 1:4), and stirred for 12 hours to prepare a 20% (w / w) precursor solution. The precursor solution was spin-coated onto a GaN substrate under a solvent atmosphere to obtain a tin-based perovskite film. Gold electrodes were then deposited onto the perovskite film to fabricate a photovoltaic detector. The device performance is described in [the table below]. Figure 51 .

[0146] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A tin-based perovskite thin film, characterized in that... First, AX, BX2, and CX are dissolved in a solvent to obtain a precursor solution. With or without functional additives, the film is prepared by recrystallization or secondary growth during in-situ crystallization in the presence of a solvent atmosphere using a solution method. The tin-based perovskite film has the general structural formula ABX3-C. x B y X z Where A is an organic or inorganic cation capable of forming three-dimensional perovskites; B is Sn 2+ Cations or Sn 2+ / Pb 2+ The mixture comprises metal cations; C is an organic cation capable of forming low-dimensional perovskites; X is a halide anion; x:y:z = 0-4:0-1:0-6, and the solvent is a mixture of DMF and DMSO in a volume ratio of 1:4 to 4:

1.

2. The tin-based perovskite thin film according to claim 1, characterized in that, The solution method includes spin coating, blade coating, inkjet printing, and screen printing; the ratio of the vapor partial pressure generated by the solvent atmosphere to the total ambient pressure is 0-0.5:

1.

3. The tin-based perovskite thin film according to claim 1, characterized in that, The halide anion is I – ,Br – Cl – F - One or a mixture thereof in any proportion; the organic or inorganic cation A capable of forming a three-dimensional structure is FA. + MA + 、Rb + Cs + One or any mixture thereof; the organic cationic component capable of forming a low-dimensional structure refers to an organic ammonium salt or an organic phosphate salt capable of forming a low-dimensional perovskite structure with BX2.

4. The tin-based perovskite thin film according to claim 3, characterized in that, The organic ammonium salt capable of forming a low-dimensional perovskite structure is one or more of alkyl ammonium salts, aromatic ammonium salts, and guanidine salts; the organic phosphorus salt capable of forming a low-dimensional perovskite structure is one or more of tetraethyl phosphorus halide, tetrabutyl phosphorus halide, and tetraphenyl phosphorus halide.

5. The tin-based perovskite thin film according to claim 1, characterized in that, The functional additives are one or more of acids and their salts, amines and their salts, and amino acids.

6. The tin-based perovskite thin film according to claim 1, characterized in that, In the precursor solution, the molar ratio of each component is AX : BX2 : CX : additive = 0.5-4 : 1 : 0-2 : 0-0.8; the total mass fraction of the precursor in the solution is 5%-70%.

7. A method for preparing a tin-based perovskite thin film according to claim 1, characterized in that... The method includes the following steps: first, AX, BX2, and CX are dissolved in a solvent to obtain a precursor solution; then, with or without the addition of functional additives, a solution method is used to allow the film to recrystallize or undergo secondary growth during in-situ crystallization in the presence of a solvent atmosphere to obtain a tin-based perovskite film; the general structural formula of the tin-based perovskite film is ABX3-C. x B y X z Where A is an organic or inorganic cation capable of forming three-dimensional perovskites; B is Sn 2+ Cations or Sn 2+ / Pb 2+ Mixed metal cations; C is an organic cation capable of forming low-dimensional perovskites; X is a halide anion; x:y:z = 0-4:0-1:0-6.

8. The application of the tin-based perovskite thin film according to claim 1 in the preparation of the active layer of optoelectronic devices.

9. The application according to claim 8, characterized in that... The aforementioned optoelectronic device is prepared by the following method: a) The transparent conductive substrate ITO glass was ultrasonically cleaned twice with acetone and ethanol respectively. After treatment, it was dried with nitrogen gas. Then the ITO was transferred to an oxygen plasma cleaner and oxygen plasma cleaned under vacuum conditions. b) The hole transport layer was prepared using a solution method and then thermally annealed; c) Prepare tin-based perovskite thin film functional layers using a solution method and perform thermal annealing; d) Electron transport layer, LiF buffer layer and Al anode layer are deposited sequentially using thermal evaporation.

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