Method for preparing perovskite film by adding leflunomide and perovskite photodetector
Patent Information
- Application Number
- CN202211631870.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-19
- Publication Date
- 2026-09-25
- Estimated Expiration
- 2042-12-19
AI Technical Summary
但同时能减少深陷阱态Pb0的研究仍然很少
[0021](1)本申请中使用的添加剂来氟米特中的C＝O，可实现对Pb2+相关缺陷的钝化，从而减少载流子非辐射复合。
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Figure CN115988935B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of perovskite film preparation, and more particularly to a method for preparing perovskite films by adding leflunomide and a perovskite photodetector. Background Technology
[0002] Organic-inorganic hybrid perovskites have become promising optoelectronic materials due to their excellent photoelectric properties, such as high carrier mobility, long carrier lifetime, and high absorption coefficient. However, perovskites are prone to decomposition when exposed to the environment (e.g., light, heat, and humidity), which needs to be addressed before commercial applications can be realized.
[0003] During perovskite preparation, defects easily arise on the surface and within the perovskite film due to their low formation energy and uncontrollable crystallization process. These defects (including interstitial sites, vacancies, and substitutions) not only serve as non-radiative recombination centers but are also susceptible to the effects of oxygen and moisture, leading to a significant deterioration in the stability and performance of the perovskite film. Therefore, the key to improving the stability of perovskite films is to reduce defects both within and on the surface of the film.
[0004] Currently, precursor solution additives are widely used as a convenient and effective method for defect passivation of perovskite thin films. Additives can influence the chemical environment in the perovskite precursor solution, thereby affecting the crystallization process of perovskite and ultimately altering the quality of the perovskite film. For example, artemisinin is used as an additive to incorporate into perovskite; the carboxyl groups in artemisinin interact with the uncoordinated Pb exposed on the MAPbI3 surface. 2+ The strong interactions between them reduce the trap density in the perovskite film. Meanwhile, the hydrophobic properties of artemisinin molecules improve device lifetime. However, most current research focuses on passivating uncoordinated ions, for example, through ionic bonds or by using coordinate bonds with opposite charges. This can simultaneously reduce the number of deep-trapped Pb states. 0 Research on this topic remains limited. Therefore, although biomolecules have achieved some success as additives, the search for new multifunctional drug molecules to achieve high-performance and stable perovskites remains urgent. Summary of the Invention
[0005] In view of this, this application provides a method for preparing perovskite films by adding leflunomide and a perovskite photodetector, which can prepare perovskite thin films with stable performance in order to control the perovskite crystallization process, passivate and reduce defects.
[0006] In a first aspect, this application provides a method for preparing perovskite films by adding the drug molecule leflunomide, comprising:
[0007] A precursor solution is provided, the precursor solution comprising a lead-based compound, a halogen compound, leflunomide, and a solvent, wherein the lead-based compound is one or more selected from PbCl2, PbBr2, PbI2, Pb(SCN)2, and Pb(CH3COO)2, the halogen compound has one or more of the following groups: A is one or more selected from CH3NH3, NH2-CH=NH2, CH3CH2NH3, CH3(CH2)2NH3, CH3(CH2)3NH3, Cs, Li, and Na, and X is one or more selected from F, Cl, Br, and I;
[0008] A precursor solution is coated onto a conductive glass substrate to form a wet film, and the wet film is then subjected to heat annealing to form a perovskite thin film.
[0009] It is already known that the structural formula of leflunomide is:
[0010]
[0011] Suitable, but not limiting, specific examples include leflunomide added in molar amounts of 0.1 to 3.2 mol% of the lead-based compound.
[0012] Suitable, but not limiting, specific examples include the precursor solution being a solvent selected from one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethyl carbonate, and γ-butyrolactone.
[0013] Suitable, but not limiting, specific examples include a precursor solution with a molar concentration of 0.1 to 2 mol / mL.
[0014] Suitable, but not limiting, specific examples show that the molar ratio of the lead-based compound to the halogen compound is 1:1 to 3.
[0015] Suitable but not limiting specific examples include heating and annealing at a temperature not exceeding 100°C and an annealing time of 10–15 min.
[0016] Suitable, but not limiting, specific examples show that the coating is applied in an environment with an air humidity of less than 50%.
[0017] Secondly, this application provides a perovskite photodetector, comprising a conductive glass substrate, a perovskite thin film, and a metal electrode stacked sequentially, wherein the perovskite thin film is obtained by the method described in claim 1.
[0018] Suitable, but not limiting, specific examples include the conductive glass substrate being one or more of an ITO transparent electrode and an FTO transparent electrode.
[0019] Suitable, but not limiting, specific examples include one or more of alloys and metal electrodes.
[0020] Compared with the prior art, this application has the following beneficial effects:
[0021] (1) The C=O in the additive leflunomide used in this application can achieve the effect of controlling Pb. 2+ Passivation of related defects reduces nonradiative recombination of charge carriers.
[0022] (2) The introduction of leflunomide in this application can reduce deep-level defects Pb 0 .
[0023] (3) The perovskite thin film prepared by this application has better quality and higher crystallinity.
[0024] (4) The trifluoromethyl group on the additive leflunomide used in this application is hydrophobic and interacts with the MA on the perovskite. + Strong hydrogen bonds can form between the groups, reducing the erosion of perovskite by moisture and oxygen in the air.
[0025] (5) The introduction of leflunomide can regulate the energy level alignment of the perovskite film, which helps to promote the separation, extraction and transport of charge carriers.
[0026] (6) The perovskite film prepared by this application has improved surface hydrophobicity and reduced defects, which enhances the humidity and thermal stability of the perovskite film.
[0027] (7) The perovskite photodetector prepared in this application has high responsivity, high photoelectric detection efficiency, and good device performance stability. Attached Figure Description
[0028] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.
[0029] Figure 1 This is a schematic flowchart of the perovskite thin film preparation method of this application;
[0030] Figure 2 The image shows the SEM characterization spectrum of the perovskite thin film prepared in Example 1.
[0031] Figure 3 This is the ultraviolet absorption spectrum of the perovskite thin film prepared in Example 1.
[0032] Figure 4 The photocurrent diagrams are for the two perovskite thin films prepared in Example 1.
[0033] Figure 5The images show the photoluminescence spectra of the three perovskite thin films prepared in Example 2.
[0034] Figure 6 The figure shows the ratio of lead iodide to perovskite (110) crystal planes in the perovskite thin film prepared in Example 3 after heating at 150 degrees Celsius for 0–5 hours. Detailed Implementation
[0035] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0036] Example 1
[0037] This embodiment provides a method for preparing perovskite films by adding leflunomide, including the following steps:
[0038] Step 1: Base cleaning
[0039] ITO glass with dimensions of 1.5×1.5cm was ultrasonically cleaned for 15 minutes each in deionized water, acetone, isopropanol and ethanol, dried with a nitrogen gun and then subjected to ultraviolet ozone treatment for 20 minutes.
[0040] Step 2, Preparation of perovskite precursor solution:
[0041] Pure PbI₂ and MAI (methylamine) were dissolved in a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a molar ratio of 1:1 (V₁:V₂ = 9:1). Leflunomide was added at a lead iodide molar ratio of 0 and 0.4 mol%. The mixture was then stirred overnight at 60 °C to obtain a 1.3 M perovskite precursor solution. After stirring, the solution was filtered. 50 μl of the perovskite precursor solution was pipetted onto a UV-ozone-treated ITO glass plate and spin-coated at 3000 rpm for 30 s. Chlorobenzene was added rapidly and uniformly at the 10th second of spin-coating.
[0042] Step 3, Annealing
[0043] The perovskite wet film spin-coated in step 2 was annealed using a hot plate at a temperature of 100°C for 10 minutes to obtain the perovskite film.
[0044] The method for fabricating a perovskite photodetector based on the above-mentioned perovskite film is as follows:
[0045] A metal electrode layer was uniformly deposited on the perovskite film using a vacuum evaporation apparatus, and the film thickness monitor showed that the final thickness was 50 nm.
[0046] Figure 2 The figure shows the SEM characterization spectra of the two perovskite films prepared in this embodiment. As can be seen from the figure, the film quality is better after doping with leflunomide.
[0047] Figure 3 The figure shows the UV absorption spectra of the two perovskite films prepared in this embodiment. As can be seen from the figure, all films exhibit a typical MAPbI3 absorption spectrum around 780 nm. When leflunomide is added, the perovskite film has the strongest absorption, indicating that the film quality is the best.
[0048] Figure 4 The figure shows the photocurrent diagrams of the two perovskite thin films prepared in this embodiment.
[0049] Example 2
[0050] This embodiment provides a method for preparing perovskite films based on the drug molecule leflunomide additive and its optoelectronic applications. The difference between this embodiment and Embodiment 1 is as follows:
[0051] Preparation of perovskite precursor solution: Pure PbI₂ and MAI (methylamine) were dissolved in a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a molar ratio of 1:1 (V₁:V₂ = 9:1). Leflunomide was added at lead iodide molar ratios of 0.2, 0.4, and 3.2 mol%, and the solution was stirred overnight at 60 °C to obtain a 1.3 M perovskite precursor solution. After stirring, the solution was filtered. 50 μl of the perovskite precursor solution was pipetted onto a UV-ozone-treated ITO glass plate and spin-coated at 3000 rpm for 30 s. Chlorobenzene was added rapidly and uniformly at the 10th second of spin-coating.
[0052] Figure 5 The figure shows the photoluminescence spectra of the three perovskite thin films prepared in this embodiment. It can be seen from the figure that the photoluminescence intensity is the highest when the leflunomide doping amount is 0.4 mol.%, which indicates that nonradiative recombination is reduced.
[0053] Example 3
[0054] This embodiment provides a method for preparing a perovskite film based on nanosecond pulsed laser annealing and molybdenum disulfide doping, and its optoelectronic applications. The difference between this embodiment and Embodiment 1 is as follows:
[0055] Preparation of perovskite precursor solution: Pure PbI₂ and MAI (methylamine) were dissolved in a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a molar ratio of 1:1 (V₁:V₂ = 4:1). Leflunomide was added at a lead iodide molar ratio of 0.4 mol%. The solution was then stirred overnight at 60°C to obtain a 1.3 M perovskite precursor solution. After stirring, the solution was filtered. 50 μl of the perovskite precursor solution was pipetted and evenly spread onto an ITO glass plate treated with UV ozone. The plate was spin-coated at 3000 rpm for 30 s. Chlorobenzene was added rapidly and evenly dropwise at the 10th second of spin-coating.
[0056] Figure 6 The figure shows the ratio of lead iodide to the perovskite (110) crystal plane after heating at 150 degrees Celsius for 0-5 hours. It can be seen from the figure that the perovskite film exhibits the best thermal stability after leflunomide doping.
[0057] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.
Claims
1. A method for preparing perovskite films by adding leflunomide, characterized in that, include: A precursor solution is provided, the precursor solution comprising a lead-based compound, a halogen compound, leflunomide, and a solvent, wherein the lead-based compound is one or more selected from PbCl2, PbBr2, PbI2, Pb(SCN)2, and Pb(CH3COO)2, the halogen compound has one or more of the following groups: A is one or more selected from CH3NH3, NH2-CH=NH2, CH3CH2NH3, CH3(CH2)2NH3, CH3(CH2)3NH3, Cs, Li, and Na, and X is one or more selected from F, Cl, Br, and I; The leflunomide is used to: achieve Pb saturation via its C=O functional group. 2+ Passivation of related defects, improved hydrophobicity through its trifluoromethyl group, and through interaction with MA + The formation of hydrogen bonds by the functional groups reduces the erosion of perovskite by moisture and oxygen in the air, and also reduces deep-level defects in Pb. 0 ; A precursor solution is coated onto a conductive glass substrate to form a wet film, and the wet film is then subjected to heat annealing to form a perovskite thin film.
2. The method according to claim 1, characterized in that, The molar amount of leflunomide added is 0.1 to 3.2 mol of the molar amount of the lead-based compound.
3. The method according to claim 1, characterized in that, The solvent of the precursor solution is one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethyl carbonate, and γ-butyrolactone.
4. The method according to claim 1, characterized in that, The molar concentration of the precursor solution is 0.1–2 mol / mL.
5. The method according to claim 1, characterized in that, The molar ratio of the lead-based compound to the halogen compound is 1:1 to 3.
6. The method according to claim 1, characterized in that, The annealing temperature is not higher than 100°C, and the annealing time is 10 to 15 minutes.
7. The method according to claim 1, characterized in that, The coating is applied in an environment with an air humidity of less than 50%.
8. A perovskite photodetector, characterized in that, It includes a conductive glass substrate, a perovskite thin film, and a metal electrode stacked sequentially, wherein the perovskite thin film is obtained by the method described in claim 1.
9. The perovskite photodetector according to claim 8, characterized in that, The conductive glass substrate is one or more of ITO transparent electrode and FTO transparent electrode.
10. The perovskite photodetector according to claim 8, characterized in that, The metal electrode is an alloy.