Stable perovskite material based on dme-pda additive and method of preparation
By introducing the diamine cation DMePDAI2 into the FAMAPbI3 system, a DJ-type quasi-two-dimensional perovskite structure was constructed, which solved the problem of increased dark current in three-dimensional perovskite materials under high bias voltage, achieved efficient charge transport and ion migration suppression, and improved the performance of X-ray detectors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUAZHONG UNIV OF SCI & TECH
- Filing Date
- 2026-01-30
- Publication Date
- 2026-06-19
AI Technical Summary
Existing three-dimensional perovskite materials exhibit significantly increased dark current and decreased response stability under high bias voltage, making it difficult to simultaneously achieve efficient charge transport and ion migration suppression, thus creating a technical contradiction where it is difficult to obtain both 'high-resistivity state' and 'high-throughput state'.
Diamine cations DMePDAI2 were introduced into the FAMAPbI3 system to construct a DJ-type quasi-two-dimensional perovskite structure. By eliminating van der Waals gaps in the RP structure and shortening the interlayer spacing, a network for controlling the n-value of the DMePDA(FA0.5MA0.5)n-1PbnI3n+1 material was established.
It effectively suppressed ion migration, improved carrier mobility, and achieved a comprehensive performance improvement of low dark current, high sensitivity and low noise, providing a stable and scalable material and process basis for low-dose, high-resolution X-ray imaging.
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Figure CN122248945A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of X-ray detection materials technology, and more specifically, relates to a stable perovskite material based on DMePDA additive and its preparation method. Background Technology
[0002] X-ray imaging systems convert X-ray signals penetrating objects into electrical signals using detectors, and the image quality directly depends on the physical properties of the detector materials. Due to the need for efficient absorption of high-energy photons in clinical CT and industrial inspection scenarios, detectors typically need to operate at thicknesses ranging from hundreds of micrometers to millimeters and be subject to high bias voltages, placing stringent demands on the overall performance of the detector materials. Halide perovskite materials, with their strong X-ray absorption capabilities resulting from their high atomic number composition and the advantage of being able to directly prepare thick films or single crystals using solution methods, have become a key research direction for next-generation direct detectors.
[0003] However, while traditional three-dimensional perovskite (such as MAPbI3 and FAPbI3) thick films or single crystals achieve high sensitivity, their inherent ion migration and high defect density lead to a significant increase in dark current and a decrease in response stability under high bias voltages, severely limiting their practical applications. To suppress ion migration, Ruddlesden-Popper quasi-two-dimensional structures constructed by introducing large-sized organic cations have been developed. Although this effectively improves resistivity, the obstruction of interlayer charge transport causes a nearly two-order-of-magnitude decrease in carrier mobility compared to three-dimensional structures, creating a technical contradiction where "high-resistivity" and "high-throughput" states are difficult to achieve simultaneously. How to effectively suppress ion migration and dark current under high fields while maintaining efficient charge transport capabilities has become a key technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention
[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a stable perovskite material based on DMePDA additive and its preparation method. By introducing diamine cations DMePDAI2 into the FAMAPbI3 system, a DJ-type quasi-two-dimensional perovskite structure is constructed, while simultaneously establishing DMePDA (FA... 0.5 MA 0.5 ) n-1 Pb n I 3n +1 The n-value control network of the material eliminates van der Waals gaps and shortens interlayer spacing in the RP structure, which suppresses ion migration while maintaining effective charge transport. This solves the technical difficulty in the prior art that the requirements of carrier transport, ion migration and dark current cannot be met simultaneously.
[0006] To achieve the above objectives, according to a first aspect of the present invention, a method for preparing a stable perovskite material based on a DMePDA additive is provided, comprising the following steps: Step 1: Prepare a PI-NMP solution, wherein the solutes in the solution are p-phenylenediamine and 3,3',4,4'-biphenyltetracarboxylic dianhydride, and the solvent is N-methylpyrrolidone; stir overnight. Step 2: Prepare a PI-NMP-MPI solution, wherein the solute in the solution is the PI-NMP solution prepared in Step 1 above, N,N-dimethylformamide, methylammonium iodide and lead iodide, and stir overnight; Step 3: Take the PI-NMP-MPI solution obtained in Step 2 above and uniformly cover it on the thin film transistor substrate. After two spin coating steps, anneal on a hot stage to obtain the TFT / PI seed layer. Step 4, prepare DMePDA (FA) 0.5 MA 0.5 ) n-1 Pb n I 3n+1 The γ-butyrolactone solution was completely dissolved and then transferred to a crystallizing dish, which was then allowed to stand on a hot plate. Step 5: When black grains precipitate in the solution, the TFT / PI seed layer obtained in step 3 is placed in the solvent, taken out and annealed on a hot plate to obtain a DJ-type quasi-two-dimensional perovskite thick film sample. Step 6, prepare BA2 (FA) 0.5 MA 0.5 ) n-1 Pb n I 3n+1 The γ-butyrolactone solution was completely dissolved and then transferred to a crystallizing dish, which was then allowed to stand on a hot plate. Step 7: When black crystals precipitate in the solution, put the seed layer obtained in step 3 into the solvent, take it out and anneal it on a hot plate to obtain an RP-type quasi-two-dimensional perovskite thick film sample. Step 8: Cover the surface of the perovskite thick film prepared in steps 5 and 7 with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain a TFT / PI / DMePDA (FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au and TFT / PI / BA2(FA 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device.
[0007] Preferably, in step 1, the solution concentration is 0.1 mmol / L to 3 mol / L, the stirring temperature is 30 to 60 °C, and the stirring time is 8 to 12 hours.
[0008] Preferably, in step 2, the solution concentration is 1 mol / L to 10 mol / L, the stirring temperature is 20 to 50 ℃, and the time is 8 to 12 hours.
[0009] Preferably, in step 3, the first spin coating speed is 200-800 rpm and the spin coating time is 10-60 s; the second spin coating speed is 1000-5000 rpm and the spin coating time is 10-60 s.
[0010] Preferably, in step 3, the annealing temperature is 90–120 °C and the annealing time is 20–40 minutes.
[0011] Preferably, in step 4, the solution concentration is 1 mol / L to 10 mol / L, and the value of n is 1 to ∞.
[0012] Preferably, in step 4, the stirring temperature is 50–70 °C and the heating temperature of the hot plate is 80–100 °C.
[0013] Preferably, in step 5, the annealing temperature is 80–120 °C and the annealing time is 1–5 hours.
[0014] Preferably, in step 6, the solution concentration is 1 mol / L to 10 mol / L, and the value of n is 1 to ∞.
[0015] Preferably, in step 6, the stirring temperature is 50–70 °C and the heating temperature of the hot plate is 80–100 °C.
[0016] Preferably, in step 7, the annealing temperature is 80–120 °C and the annealing time is 1–5 hours.
[0017] Preferably, in step 8, the electrode thickness is 30–80 nm.
[0018] According to a second aspect of the present invention, a stable perovskite material based on a DMePDA additive is provided, which is prepared by the method described above for a stable perovskite material based on a DMePDA additive.
[0019] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. This invention constructs a DJ-type quasi-two-dimensional perovskite structure by introducing the diamine cation DMePDAI2 into the FAMAPbI3 system. This is because the diamine in the system has two distinct -NH3 terminals. +Bonding to the inorganic layer eliminates the van der Waals gaps in the RP structure and shortens the interlayer spacing, effectively weakening the quantum confinement of the material, thus suppressing ion migration while maintaining effective charge transport.
[0020] 2. This invention utilizes the blending of different material proportions in a perovskite system to establish DMePDA (FA). 0.5 MA 0.5 ) n- 1Pb n I 3n +1 The material's n-value modulated network, in which the carrier mobility of the high-n through-network is significantly improved, results in an X-ray detector fabricated using this material exhibiting extremely low dark current density and excellent X-ray sensitivity under low / medium bias, achieving a balance between low noise and high response. This invention achieves a comprehensive improvement in the material's performance, combining low dark current, high sensitivity, and low mobility, providing a stable and scalable material and process foundation for low-dose, high-resolution X-ray imaging. Attached Figure Description
[0021] Figure 1 These are schematic diagrams of the cross-sectional morphology of DJ-type perovskite thick films with different n values in embodiments of the present invention; Figure 2 This is a schematic diagram of the photoluminescence spectra of different n values (DJ quasi-two-dimensional) and three-dimensional perovskite thick films in embodiments of the present invention; Figure 3 This is a schematic diagram showing the carrier mobility of perovskite thick films with different structures in embodiments of the present invention; Figure 4 This is a schematic diagram illustrating the electrical performance of quasi-two-dimensional and three-dimensional perovskite thick-film devices according to embodiments of the present invention; Figure 5 This is a schematic diagram illustrating the ghosting performance of quasi-two-dimensional and three-dimensional perovskite X-ray array detectors in an embodiment of the present invention. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0023] An embodiment of the present invention is a stable perovskite material based on DMePDA additive and its preparation method, comprising the following steps: Example 1 Fabrication of DJ-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0024] (2) Prepare 1.5 M DMePDA (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 1, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed on a hot plate at 100 °C for 4 h. After natural cooling, a perovskite thick film sample was obtained.
[0025] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain a TFT / PI / DMePDA (FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706 cm² 2 .
[0026] Example 2 Fabrication of DJ-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0027] (2) Prepare 1.5 M DMePDA (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 2, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed at 100 °C for 4 h on a hot plate. After natural cooling, a perovskite thick film sample was obtained.
[0028] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain a TFT / PI / DMePDA (FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706 cm² 2 .
[0029] Example 3 Fabrication of DJ-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0030] (2) Prepare 1.5 M DMePDA (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 3, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed on a hot plate at 100 °C for 4 h. After natural cooling, a perovskite thick film sample was obtained.
[0031] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain a TFT / PI / DMePDA (FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706 cm² 2 .
[0032] Example 4 Fabrication of DJ-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0033] (2) Prepare 1.5 M DMePDA (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 4, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed on a hot plate at 100 °C for 4 h. After natural cooling, a perovskite thick film sample was obtained.
[0034] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain a TFT / PI / DMePDA (FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706 cm² 2 .
[0035] Example 5 Fabrication of DJ-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0036] (2) Prepare 1.5 M DMePDA (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 10, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed at 100 °C for 4 h on a hot plate. After natural cooling, a perovskite thick film sample was obtained.
[0037] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain a TFT / PI / DMePDA (FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706 cm² 2 .
[0038] Example 6 Fabrication of RP-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0039] (2) Prepare 1.5 M BA2 (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 1, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed on a hot plate at 100 °C for 4 h. After natural cooling, a perovskite thick film sample was obtained.
[0040] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain TFT / PI / BA2(FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706cm² 2 .
[0041] Example 7 Fabrication of RP-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0042] (2) Prepare 1.5 M BA2 (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 2, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed on a hot plate at 100 °C for 4 h. After natural cooling, a perovskite thick film sample was obtained.
[0043] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain TFT / PI / BA2(FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706cm² 2 .
[0044] Example 8 Fabrication of RP-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of the PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, then spin-coated at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0045] (2) Prepare 1.5 M BA2 (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 3, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed on a hot plate at 100 °C for 4 h. After natural cooling, a perovskite thick film sample was obtained.
[0046] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain TFT / PI / BA2(FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706cm² 2 .
[0047] Example 9 Fabrication of RP-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0048] (2) Prepare 1.5 M BA2 (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 4, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed at 100 °C for 4 h on a hot plate. After natural cooling, a perovskite thick film sample was obtained.
[0049] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain TFT / PI / BA2(FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706cm² 2 .
[0050] Example 10 Fabrication of RP-type quasi-two-dimensional perovskite X-ray detectors (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0051] (2) Prepare 1.5 M BA2 (FA) in a beaker. 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 10, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 90 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 90 °C for 60 min. The seed layer was then removed and annealed at 100 °C for 4 h on a hot plate. After natural cooling, a perovskite thick film sample was obtained.
[0052] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain TFT / PI / BA2(FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706cm² 2 .
[0053] Comparative Example 1 Fabrication of a three-dimensional perovskite X-ray detector (1) 2.86 g of p-phenylenediamine and 1.08 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to 22.35 g of N-methylpyrrolidone solvent and stirred overnight at 40 °C to obtain a PI-NMP solution. 4.8 g of PI-NMP, 2.4 g of N,N-dimethylformamide, 1.59 g of methylammonium iodide and 4.61 g of lead iodide were mixed uniformly and stirred overnight at room temperature to obtain a PI-NMP-MPI solution. 320 μL of PI-NMP-MPI solution was uniformly coated onto a thin-film transistor substrate with a pixel array of 64×64 and a pixel size of 200 μm. The substrate was spin-coated at 600 r / min for 20 s, followed by spin-coating at 2000 r / min for 40 s, and then annealed at 100 °C for 30 min on a hot plate to obtain a TFT / PI seed layer.
[0054] (2) Prepare 1.5 M (FA) in a beaker 0.5 MA 0.5 ) n-1 Pb n I 3n+1 A solution of γ-butyrolactone, where n is 1, was stirred at 60 °C until completely dissolved and then transferred to a crystallizing dish. The solution was then placed on a hot plate at 80 °C. When black crystals precipitated in the solution, the obtained TFT / PI seed layer was placed in the solvent and kept at 80 °C for 60 min. The seed layer was then removed and annealed on a hot plate at 100 °C for 4 h. After natural cooling, a perovskite thick film sample was obtained.
[0055] (3) Cover the surface of the perovskite thick film prepared in the above steps with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain TFT / PI / (FA) 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device structure, electrode area is 0.0706cm² 2 .
[0056] Performance testing of two-dimensional perovskite materials The cross-sectional structure, optical properties, and electrical properties of the two-dimensional perovskite materials prepared in the above embodiments and comparative examples were tested, and the results are shown in the figure. Figure 1 , Figure 2 and Figure 3 ; Figure 1The figures show the microscopic cross-sectional structures of the DJ-type and RP-type quasi-two-dimensional perovskite materials prepared in Examples 1-10 at different n values. It is clearly observed that, compared to the generally porous, smaller-grained, and less uniform RP-type quasi-two-dimensional perovskite thick films, the grain size in the DJ-type quasi-two-dimensional perovskite thin films gradually increases with increasing n value. This indicates that the present invention can reduce the grain boundary density of perovskite materials, shorten the interlayer distance, thereby further reducing the defect density, mitigating the carrier localization effect, and improving charge transport.
[0057] Figure 2 The images show the photoluminescence spectra of the DJ-type quasi-two-dimensional perovskite materials prepared in Examples 1-5. It can be seen that increasing the n value leads to a gradual redshift of the single PL peak and a narrowing of the full width at half maximum (FWHM). This indicates that the present invention can reduce the van der Waals gaps in the overall perovskite structure, thus ensuring carrier transport capability.
[0058] Figure 3 The figures show the carrier mobility test results for the DJ-type and RP-type quasi-two-dimensional perovskite materials prepared in Examples 1-10 at different n values. When n is 4, the mobility of the RP-type perovskite is 4.43 cm⁻¹. 2 V -1 s -1 The mobility of DJ-type perovskite reached 13.7 cm⁻¹. 2 V -1 s -1 This demonstrates that the mobility is comparable to that of widely used three-dimensional perovskites. This indicates that the present invention can significantly improve carrier mobility, thereby increasing the photoelectric conversion efficiency and response speed of the device.
[0059] Performance testing of perovskite X-ray detectors The electrical performance and artifact testing were performed on the perovskite X-ray detectors prepared in the above embodiments and comparative examples, and the results are as follows: Figure 4 and Figure 5 As shown; Figure 4 The figures show the dark current density test graphs, X-ray response curves, and sensitivity curves at different bias voltages for the perovskite X-ray detectors prepared in Example 4 and Comparative Example 1, respectively. It can be seen that the DJ-type perovskite X-ray detector with an n value of 4 has lower dark current density and drift compared to the three-dimensional perovskite X-ray detector. Specifically, at a bias voltage of 100 V, the dark current density of the three-dimensional perovskite X-ray detector is 1.86 × 10⁻⁶. -7 A cm -2 When n=4, the dark current density of the DJ-type quasi-two-dimensional tackwell X-ray detector is 4.04 × 10⁻⁶. -8 A cm-2 Furthermore, the sensitivities at 1 V and 20 V bias voltages are approximately 1184 and 8243 μC Gy, respectively. air -1 cm -2 This demonstrates that the present invention can comprehensively improve low dark current, high sensitivity, and low migration performance without sacrificing device sensitivity.
[0060] Figure 5 The artifact testing of the perovskite X-ray detectors prepared in Example 4 and Comparative Example 1 is shown. It can be seen that the X-ray exposure images obtained using the thick-film device fabricated with three-dimensional perovskite show clear boundary edges with a difference as high as 7.5%, while the ghosting effect of the device fabricated with quasi-2D perovskite thick film is almost negligible, with a difference of only 1.6%. This indicates that the present invention significantly enhances anti-ghosting ability, has stronger inter-frame stability, and can effectively suppress imaging artifacts.
[0061] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing a stable perovskite material based on DMePDA additive, characterized in that, Includes the following steps: Step 1: Prepare a PI-NMP solution with p-phenylenediamine and 3,3',4,4'-biphenyltetracarboxylic dianhydride as the solutes and N-methylpyrrolidone as the solvent, and stir overnight; Step 2: Prepare a PI-NMP-MPI solution, the solute of which is the PI-NMP solution prepared in Step 1 above, N,N-dimethylformamide, methylammonium iodide and lead iodide, and stir the solvent overnight; Step 3: Take the PI-NMP-MPI solution obtained in Step 2 above and uniformly cover it on the thin film transistor substrate. After two spin coating steps, anneal on a hot stage to obtain the TFT / PI seed layer. Step 4, prepare DMePDA (FA) 0.5 MA 0.5 ) n-1 Pb n I 3n+1 The γ-butyrolactone solution was completely dissolved and then transferred to a crystallizing dish, which was then allowed to stand on a hot plate. Step 5: When black grains precipitate in the solution, the TFT / PI seed layer obtained in step 3 is placed in the solvent, taken out and annealed on a hot plate to obtain a DJ-type quasi-two-dimensional perovskite thick film sample. Step 6, prepare BA2 (FA) 0.5 MA 0.5 ) n-1 Pb n I 3n+1 The γ-butyrolactone solution was completely dissolved and then transferred to a crystallizing dish, which was then allowed to stand on a hot plate. Step 7: When black crystals precipitate in the solution, put the seed layer obtained in step 3 into the solvent, take it out and anneal it on a hot plate to obtain an RP-type quasi-two-dimensional perovskite thick film sample. Step 8: Cover the surface of the perovskite thick film prepared in steps 5 and 7 with a specific mask, and deposit an 80 nm thick Au electrode using thermal evaporation technology to obtain a TFT / PI / DMePDA (FA). 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au and TFT / PI / BA2(FA 0.5 MA 0.5 ) n-1 Pb n I 3n+1 / Au device.
2. The method for preparing a stable perovskite material based on DMePDA additive according to claim 1, characterized in that, In step 1, the solution concentration is 0.1 mmol / L to 3 mol / L, the stirring temperature is 30 to 60 ℃, and the time is 8 to 12 hours.
3. The method for preparing a stable perovskite material based on DMePDA additive according to claim 1, characterized in that, In step 2, the solution concentration is 1 mol / L to 10 mol / L, the stirring temperature is 20 to 50 ℃, and the time is 8 to 12 hours.
4. A method for preparing a stable perovskite material based on a DMePDA additive according to any one of claims 1-3, characterized in that, In step 3, the first spin coating speed is 200-800 rpm and the spin coating time is 10-60 s; the second spin coating speed is 1000-5000 rpm and the spin coating time is 10-60 s.
5. The method for preparing a stable perovskite material based on DMePDA additive according to claim 4, characterized in that, In step 3, the annealing temperature is 90–120 °C, and the annealing time is 20–40 minutes.
6. A method for preparing a stable perovskite material based on a DMePDA additive according to any one of claims 1-3, characterized in that, In step 4, the solution concentration is 1 mol / L to 10 mol / L, and the value of n is 1 to ∞.
7. The method for preparing a stable perovskite material based on DMePDA additive according to claim 6, characterized in that, In step 4, the stirring temperature is 50–70 ℃, and the heating temperature of the hot plate is 80–100 ℃.
8. A method for preparing a stable perovskite material based on a DMePDA additive according to any one of claims 1-3, characterized in that, In step 5, the annealing temperature is 80–120 °C, and the annealing time is 1–5 hours.
9. A method for preparing a stable perovskite material based on DMePDA additive according to claims 1-3, characterized in that, In step 6, the solution concentration is 1 mol / L to 10 mol / L, and the value of n is 1 to ∞.
10. The method for preparing a stable perovskite material based on DMePDA additive according to claim 9, characterized in that, In step 6, the stirring temperature is 50–70 °C, and the heating temperature of the hot plate is 80–100 °C.
11. A method for preparing a stable perovskite material based on a DMePDA additive according to any one of claims 1-3, characterized in that, In step 7, the annealing temperature is 80–120 °C, and the annealing time is 1–5 hours.
12. A method for preparing a stable perovskite material based on a DMePDA additive according to any one of claims 1-3, characterized in that, In step 8, the electrode thickness is 30–80 nm.
13. A stabilized perovskite material based on DMePDA additive, characterized in that, It is prepared by the method of any one of the DMePDA additives for stabilizing perovskite materials as described in any one of claims 1-12.