Self-driven wide bandgap perovskite ultraviolet detector and preparation method thereof
A self-driven CsPbCl3-xBrx perovskite ultraviolet detector was prepared by thermal evaporation deposition and low-pressure annealing processes, solving the problem of high-quality thin film preparation and achieving low-cost, high-efficiency performance and stability improvement of the ultraviolet detector, which is suitable for large-scale commercial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING DIDA IND TECH RES INST CO LTD
- Filing Date
- 2026-02-03
- Publication Date
- 2026-05-15
AI Technical Summary
Existing technologies are insufficient for efficiently preparing high-quality CsPbCl3-xBrx perovskite thin films. The presence of numerous defects in the films limits the improvement of ultraviolet detector performance. Furthermore, traditional processes are costly and require sophisticated equipment, making large-scale applications difficult.
A CsPbCl3-xBrx photosensitive layer was prepared by continuous thermal evaporation deposition process. By controlling the film composition and defect passivation through TPPO doping and low-pressure assisted annealing, a self-driven wide-bandgap perovskite ultraviolet detector was formed, which simplifies the process and reduces costs.
This study achieved efficient and low-cost preparation of CsPbCl3-xBrx perovskite thin films, reducing device production costs and improving ultraviolet detection performance and stability, making them suitable for large-scale commercial production.
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Figure CN122054883A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ultraviolet detector technology, and in particular to a self-driven wide-bandgap perovskite ultraviolet detector and its fabrication method. Background Technology
[0002] Ultraviolet (UV) detectors, serving as the "eyes" of UV detection systems, play a crucial role in environmental monitoring, optical communication, astronomical observation, biomedicine, and security and anti-counterfeiting. The development of UV detector fabrication processes and performance tuning have become a focus of research worldwide. Currently, commercially available UV detectors are primarily fabricated using traditional inorganic semiconductor materials (GaN, Ga2O3, AsGa, etc.). These semiconductor thin films require furnace reaction or MOCVD processes, which are complex, demanding in terms of equipment, purity, and processing temperatures ranging from 800 to 1600°C, resulting in high costs and energy consumption. Furthermore, the low carrier transport efficiency of these semiconductors limits their application in high-speed UV detection. Emerging perovskite photosensitive semiconductors, with their unique optical and electrical properties such as tunable bandgap, high light absorption coefficient, low dielectric constant, few internal defects, high charge mobility, and low surface recombination rate, have become a research hotspot in optoelectronics. Currently reported perovskite photodetectors exhibit advantages over traditional photodetectors such as SiC-based, InGaAs-based, and GaN-based detectors in terms of response speed and linear dynamic range.
[0003] To achieve high-precision ultraviolet detection while reducing noise interference in the visible light band, ultraviolet photosensitive films need to have a wide optical bandgap. The wide-bandgap CsPbCl3 perovskite semiconductor has an optical bandgap of 2.99 eV and an upper absorption wavelength limit of approximately 410 nm, comparable to SiC semiconductors widely used in ultraviolet detection. Furthermore, CsPbCl3 exhibits strong photo-matter interactions, demonstrating excellent response to ultraviolet light signals and superior ultraviolet radiation stability, making it an ideal component for high-speed, high-sensitivity ultraviolet detectors. However, traditional solution processes struggle to prepare high-quality CsPbCl3 polycrystalline films, which often contain numerous defects (such as Cl vacancy defects, antisite defects, and grain boundary defects), easily leading to severe charge trapping and non-radiative recombination losses.
[0004] Halogen Br doping of CsPbCl3 perovskite forms CsPbCl 3-x Br x Perovskites, while maintaining a wide optical bandgap in perovskite semiconductors, can significantly reduce their defect state density and improve their optical and electrical properties such as light absorption and carrier mobility, making them highly promising for applications in ultraviolet detection. However, CsPbCl... 3-x Br xDuring the nucleation and growth process of perovskite films, a large number of grain boundaries and internal defects inevitably occur, leading to the presence of a large number of uncoordinated Pb within the crystal. 2+ Ions, limiting CsPbCl 3-x Br x The performance of the ultraviolet detector has been further improved.
[0005] Perovskite defect passivation strategies have been proven to be effective means of reducing defects in perovskite thin films. Studies have shown that organic molecule modification and doping can significantly suppress the defect state density of perovskites. Organic molecule modification (alkylamines, alcohols, etc.) requires consideration of the compatibility between the perovskite material and the material itself. Organic molecule modification can effectively reduce electron-hole pair recombination, but it is only applicable to organic or organic-inorganic hybrid perovskite materials, and the process is complex, requiring the introduction of other organic solvents. Doping strategies often involve incorporating different metal elements (cobalt, manganese, lead, etc.) to change the perovskite crystal structure. Complex interactions may exist between different dopant elements, leading to less than expected doping effects. Given the wide bandgap of CsPbCl... 3-x Br x Perovskite precursors exhibit low solubility in existing solvents, making their preparation and elemental doping difficult using conventional solution methods. Therefore, there is an urgent need to develop a low-cost, high-efficiency CsPbCl₂ method. 3-x Br x Methods for preparing perovskite thin films and strategies for suppressing defect states. Summary of the Invention
[0006] The purpose of this invention is to address the aforementioned shortcomings of the prior art by proposing a self-driven wide-bandgap perovskite ultraviolet detector and its fabrication method.
[0007] The first objective of this invention is to provide a method for fabricating a self-driven wide-bandgap perovskite ultraviolet detector, wherein the ultraviolet detector comprises an FTO conductive glass substrate and TPPO (triphenylphosphine oxide)-doped CsPbCl₂ deposited on the FTO glass. 3-x Br x A perovskite polycrystalline thin film and a carbon electrode layer formed on the perovskite polycrystalline thin film; the perovskite polycrystalline thin film is formed by reacting a PbCl2 precursor layer, a TPPO doped layer, a CsBr layer and a CsCl layer deposited by thermal evaporation under high temperature annealing; wherein 0.5≤x≤1.
[0008] Furthermore, the deposited PbCl2 layer has a thickness of 190-200 nm, the deposited CsBr layer has a thickness of 70-140 nm, the corresponding deposited CsCl layer has a thickness of 0-70 nm, and the TPPO doped layer has a thickness of 3-18 nm. The greater the thickness of the deposited CsBr layer, the smaller the thickness of the CsCl layer.
[0009] Furthermore, a PbCl2 precursor layer of fixed thickness is first thermally evaporated and deposited at a rate of 0.5~1 Å / s, followed by a TPPO doped layer at a rate of 0.1~0.2 Å / s, then a CsBr layer at a rate of 0.5~1 Å / s, and finally a CsCl layer at a rate of 0.5~1 Å / s.
[0010] Furthermore, in the high-temperature annealing, the pressure was set to 0.2~0.8 atm, the annealing temperature to 250~280 ℃, and the annealing time to 25~30 min. This allows CsPbCl... 3-x Br x The thin film is fully crystallized. Low-pressure assisted annealing can effectively control the nucleation and growth process of the thin film, promoting the formation of TPPO atoms in CsPbCl₂. 3-x Br x The crystal undergoes a fully diffused reaction, thereby improving grain size, light absorption performance, and carrier lifetime, while reducing grain boundary density and defect state density.
[0011] Furthermore, the carbon electrode layer is a commercially available carbon paste, and a 20-30 μm thick carbon paste is coated onto TPPO-doped CsPbCl using a blade coating process. 3-x Br x For the perovskite film surface, the carbon paste drying temperature is 120~150℃, and the drying time is 10~15min.
[0012] Furthermore, the deposition is all carried out in a high-vacuum sealed cavity, with an internal pressure not exceeding 5 × 10⁻⁶. -4 Pa.
[0013] Furthermore, the FTO conductive glass substrate was prepared by sequentially ultrasonically cleaning the laser-etched FTO conductive substrate with detergent, acetone, anhydrous ethanol, and deionized water for 20-25 minutes. The cleaned FTO glass was then immediately dried in a clean environment using a nitrogen stream and treated in an ultraviolet ozone chamber for 30-35 minutes.
[0014] A self-driven wide-bandgap perovskite ultraviolet detector prepared using the above-described preparation method.
[0015] The preparation method of this invention employs a continuous thermal evaporation deposition process to fabricate the ultraviolet detector CsPbCl. 3-x Br x The PbCl2, CsBr, and CsCl precursor layers of the photosensitive layer and the TPPO doped layer exhibit high film uniformity due to thermal evaporation deposition. Since the film thickness is directly proportional to the amount of material, precise control of the thickness of the PbCl2, CsBr, and CsCl precursor layers allows for precise control of CsPbCl... 3-x Br xPrecise control of the thin film phase composition (ensuring 0.5 ≤ x ≤ 1), and the deposition of an organic TPPO layer of a certain thickness between the PbCl2, CsBr, and CsCl precursor layers via vapor deposition, to achieve control of CsPbCl... 3-x Br x TPPO doping in thin films. The P=O groups in TPPO react with CsPbCl... 3-x Br x Uncoordinated Pb in perovskites 2+ The formation of stable P=O-Pb bonds, thereby inhibiting CsPbCl 3-x Br x This method addresses halogen (Cl and Br) vacancy defects within perovskite films, reducing both internal and surface halogen vacancy defects. It is the first to employ vapor deposition to dope organic TPPO molecules into an all-inorganic CsPbCl₂ film. 3-x In Brx perovskite, the nucleation and growth process of the thin film is favorablely controlled by a low-pressure assisted annealing process, allowing organic molecules to fully diffuse into CsPbCl. 3-x Br x The thin film achieves efficient defect passivation, reducing non-radiative recombination losses in the device. This UV detector features a simple structure, achieving excellent UV detection performance without requiring any electron / hole transport layers, modification layers, or noble metal electrode layers. This technology effectively improves the UV detection performance and stability of the device while significantly reducing its production cost, thus contributing to its commercial production and application.
[0016] This invention provides for the first time a low-cost, high-efficiency self-driven wide-bandgap CsPbCl 3-x Br x The fabrication method and performance optimization strategy of perovskite ultraviolet detectors can achieve the following beneficial effects: 1. The CsPbCl of the ultraviolet detector 3-x Br x Both the perovskite precursor layer and the organic TPPO doped layer are prepared using a vacuum thermal evaporation process, which has low equipment requirements (only one thermal evaporation device is needed), facilitating the efficient fabrication of subsequent large-area ultraviolet detector devices and detector arrays. The entire process is highly applicable, with low complexity, high repeatability, and high device fabrication efficiency, making it suitable for large-scale commercial production of ultraviolet detectors.
[0017] 2. The CsPbCl 3-x Br x The perovskite photosensitive layer is prepared by sequentially depositing a PbCl2 precursor layer, a CsBr layer, and a CsCl precursor layer, followed by high-temperature, low-pressure assisted annealing. By fixing the thickness of the PbCl2 precursor layer and adjusting the thickness ratio of the CsBr and CsCl layers, the CsPbCl layer thickness can be precisely controlled.3-x Br x The phase composition of the thin film is such that 0.5 ≤ x ≤ 1. An organic TPPO doped layer is also deposited between the PbCl2 and CsBr / CsCl layers via thermal evaporation. By changing the thickness of the TPPO doped layer, the doping amount can be precisely controlled. Given the wide bandgap of CsPbCl... 3-x Br x Perovskite precursors are difficult to dissolve simultaneously in existing solvents, making traditional solution-based organic doping methods impossible. The proposed vapor-phase evaporation doping process for TPPO effectively overcomes this difficulty, enabling the organic doping of CsPbCl₂. 3-x Br x Highly efficient and quantitative doping of perovskites. Compared to traditional solution-based processes, the proposed all-vapor evaporation process offers higher controllability and repeatability, making it more suitable for wide-bandgap CsPbCl. 3-x Br x Preparation of perovskite thin films. Furthermore, this method does not use any toxic solvents, making it environmentally friendly.
[0018] 3. For CsPbCl 3-x Br x To effectively passivate perovskite defects, inexpensive organic TPPO is first used as a dopant. The P=O groups in TPPO react with CsPbCl... 3-x Br x uncoordinated Pb 2+ The formation of stable P=O-Pb bonds, thereby inhibiting CsPbCl 3-x Br x Halogen vacancy defects within and at grain boundaries of perovskite thin films. Subsequently, a low-pressure assisted annealing process was developed to improve CsPbCl... 3-x Br x The nucleation and crystallization process of perovskite increases grain size, light absorption performance, and carrier lifetime, while reducing grain boundary density and defect state density, thus promoting the improvement of the optical and electrical properties of perovskite thin films.
[0019] 4. The designed wide-bandgap CsPbCl 3-x Br x The perovskite ultraviolet detector is a vertically stacked, self-powered device that can autonomously perform ultraviolet light detection without an external power supply, reducing system power consumption and complexity. Furthermore, the device achieves excellent ultraviolet detection performance without using any electron / hole transport layers, modification layers, or noble metal electrode layers, significantly reducing production costs and facilitating its commercial production and application. Attached Figure Description
[0020] Figure 1 Self-driven CsPbCl doped with TPPO 3-x Brx A schematic diagram of the fabrication process for perovskite ultraviolet detectors; Figure 2 Self-driven CsPbCl doped with TPPO 3-x Br x Schematic diagram of an ultraviolet detector. Detailed Implementation
[0021] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.
[0022] Please see Figure 1 The preferred embodiment of the present invention provides a method for fabricating a self-driven wide-bandgap perovskite ultraviolet detector based on a vapor-phase doping and low-pressure assisted annealing strategy, which mainly includes the following steps: Step 1: Provide a glass substrate with an FTO conductive layer and clean the FTO glass substrate.
[0023] Specifically, an FTO conductive glass substrate is provided, and the laser-etched FTO conductive substrate is ultrasonically cleaned sequentially with detergent, acetone, anhydrous ethanol, and deionized water for 20-25 minutes. The cleaned FTO glass is immediately dried in a clean environment with nitrogen gas flow, and then treated in an ultraviolet ozone chamber for 30-35 minutes.
[0024] Step 2: Prepare TPPO-doped CsPbCl on the FTO conductive layer using a vapor deposition process. 3-x Br x Perovskite photosensitive film.
[0025] Specifically, a 200 nm thick PbCl2 precursor layer is first deposited on the FTO conductive layer using a vacuum thermal evaporation process, followed by a 3-18 nm TPPO doped layer, then a 70-140 nm CsBr precursor layer, and finally a 0-70 nm CsCl precursor layer (the thicker the CsBr layer, the thinner the CsCl layer), thus completing the TPPO-doped CsPbCl2 layer. 3-x Br x Thin film deposition was performed with the evaporation rates of PbCl2, CsBr, and CsCl layers controlled at 0.5–1 Å / s (measured using a film thickness gauge), and the evaporation rate of the TPPO doped layer controlled at 0.1–0.2 Å / s. The entire thin film deposition process was carried out under a pressure less than 5 × 10⁻⁶ Å / s. -4 The procedure is performed within a high-vacuum chamber.
[0026] Step 3: The deposited CsPbCl₂ is processed in a tube furnace. 3-x Br x The perovskite thin film is subjected to low-pressure assisted annealing.
[0027] Specifically, CsPbCl3 is processed in the tubular furnace equipped with a vacuum device. 3-x Br x The perovskite was annealed, with the internal pressure monitored by a barometer and set to 0.2–0.8 atm. The temperature inside the tubular furnace was set to 250–280 °C, and the low-pressure annealing time was set to 25–30 min. This was applied to CsPbCl... 3-x Br x The nucleation and growth processes of thin films are favorablely regulated to ensure sufficient crystallization of the film and to facilitate the formation of TPPO in CsPbCl₂. 3-x Br x Uniform doping is achieved through thorough diffusion within the perovskite, and passivation of CsPbCl is achieved through the formation of P=O-Pb bonds between the two. 3-x Br x The purpose is to address halogen vacancy defects within and at grain boundaries of perovskites.
[0028] Step four, after annealing, TPPO-doped CsPbCl 3-x Br x Carbon electrodes are coated onto the perovskite photosensitive layer.
[0029] Specifically, in the prepared CsPbCl 3-x Br x A layer of commercial carbon paste, approximately 20-30 μm thick, is applied to the substrate using a coating knife. It is then heated on a hot plate at 120-150°C for 10-15 minutes to dry, forming a stable carbon counter electrode. This completes the wide-bandgap CsPbCl... 3-x Br x Fabrication of perovskite ultraviolet detectors. Please refer to [link to overall device structure] for details. Figure 2 .
[0030] Example 1 The first embodiment of this invention provides a method for fabricating a self-driven wide-bandgap perovskite ultraviolet detector based on a vapor-phase doping and low-pressure assisted annealing strategy, which mainly includes the following steps: A1 provides a glass substrate with an FTO conductive layer and cleans the FTO glass substrate.
[0031] Specifically, an FTO conductive glass substrate is provided, and the laser-etched FTO conductive substrate is ultrasonically cleaned sequentially with detergent, acetone, anhydrous ethanol, and deionized water for 20 minutes each. The cleaned FTO glass is immediately dried in a clean environment with nitrogen gas flow and then treated in an ultraviolet ozone chamber for 30 minutes.
[0032] A2, TPPO-doped CsPbCl₂ is prepared on the FTO conductive layer using a vapor deposition process. 3-xBr x Perovskite photosensitive film.
[0033] Specifically, a 200nm thick PbCl2 precursor layer is first deposited on the FTO conductive layer using a vacuum thermal evaporation process, followed by a 6nm TPPO doped layer, then a 70nm CsBr precursor layer, and finally a 70nm CsCl precursor layer, completing the TPPO-doped CsPbCl2 layer. 3-x Br x Thin film deposition was performed with the evaporation rates of PbCl2, CsBr, and CsCl layers controlled at 0.5 Å / s, and the evaporation rate of the TPPO doped layer controlled at 0.1 Å / s. The entire thin film deposition process was carried out at a pressure less than 5 × 10⁻⁶ Å / s. -4 The procedure is performed within a high-vacuum chamber.
[0034] A3, CsPbCl deposited in a tube furnace 3-x Br x The perovskite thin film is subjected to low-pressure assisted annealing.
[0035] Specifically, CsPbCl3 is processed in the tubular furnace equipped with a vacuum device. 3-x Br x The perovskite was annealed, with the internal pressure monitored by a barometer at 0.3 atm. The furnace temperature was set to 260℃, and the low-pressure annealing time was set to 25 min. This was applied to CsPbCl... 3-x Br x The nucleation and growth processes of thin films are favorablely regulated to ensure sufficient crystallization of the film and to facilitate the formation of TPPO in CsPbCl₂. 3-x Br x Uniform doping is achieved through thorough diffusion within the perovskite, and passivation of CsPbCl is achieved through the formation of P=O-Pb bonds between the two. 3-x Br x The purpose is to address halogen vacancy defects within and at grain boundaries of perovskites.
[0036] A4, TPPO-doped CsPbCl after annealing 3-x Br x Carbon electrodes are coated onto the perovskite photosensitive layer.
[0037] Specifically, in the prepared CsPbCl 3-x Br x A layer of commercial carbon paste, approximately 25 μm thick, is applied to the substrate using a coating knife. This paste is then heated on a 130°C hot plate for 12 minutes to dry, forming a stable carbon counter electrode. This completes the wide-bandgap CsPbCl... 3-x Br x Fabrication of the perovskite ultraviolet detector. Its performance test results are shown in Table 1.
[0038] Example 2 The second embodiment of the present invention provides a method for fabricating a self-driven wide-bandgap perovskite ultraviolet detector based on a vapor-phase doping and low-pressure assisted annealing strategy, which mainly includes the following steps: B1, providing a glass substrate with an FTO conductive layer, and cleaning the FTO glass substrate.
[0039] Specifically, an FTO conductive glass substrate is provided, and the laser-etched FTO conductive substrate is ultrasonically cleaned sequentially with detergent, acetone, anhydrous ethanol, and deionized water for 25 minutes. The cleaned FTO glass is immediately dried in a clean environment with nitrogen gas flow and then treated in an ultraviolet ozone chamber for 32 minutes.
[0040] B2, TPPO-doped CsPbCl is prepared on the FTO conductive layer using a vapor deposition process. 3-x Br x Perovskite photosensitive film.
[0041] Specifically, a 200 nm thick PbCl2 precursor layer is first deposited on the FTO conductive layer using a vacuum thermal evaporation process, followed by a 9 nm TPPO doped layer, then a 90 nm CsBr precursor layer, and finally a 50 nm CsCl precursor layer, completing the TPPO-doped CsPbCl2 layer deposition. 3-x Br x Thin film deposition was performed with the evaporation rates of PbCl2, CsBr, and CsCl layers controlled at 0.7 Å / s, and the evaporation rate of the TPPO doped layer controlled at 0.15 Å / s. The entire thin film deposition process was carried out at a pressure less than 5 × 10⁻⁶ Å / s. -4 The procedure is performed within a high-vacuum chamber.
[0042] B3, CsPbCl deposited in a tube furnace 3-x Br x The perovskite thin film is subjected to low-pressure assisted annealing.
[0043] Specifically, CsPbCl3 is processed in the tubular furnace equipped with a vacuum device. 3-x Br x The perovskite was annealed, with the internal pressure monitored by a barometer at 0.5 atm. The furnace temperature was set to 260℃, and the low-pressure annealing time was set to 25 min. This was applied to CsPbCl... 3-x Br x The nucleation and growth processes of thin films are favorablely regulated to ensure sufficient crystallization of the film and to facilitate the formation of TPPO in CsPbCl₂. 3-x Br xUniform doping is achieved through thorough diffusion within the perovskite, and passivation of CsPbCl is achieved through the formation of P=O-Pb bonds between the two. 3-x Br x The purpose is to address halogen vacancy defects within and at grain boundaries of perovskites.
[0044] B4, TPPO-doped CsPbCl after annealing 3-x Br x Carbon electrodes are coated onto the perovskite photosensitive layer.
[0045] Specifically, in the prepared CsPbCl 3-x Br x A layer of commercial carbon paste, approximately 30 μm thick, is applied to the substrate using a coating knife. This paste is then heated on a 130°C hot plate for 12 minutes to dry, forming a stable carbon counter electrode. This completes the wide-bandgap CsPbCl... 3-x Br x Fabrication of the perovskite ultraviolet detector. Its performance test results are shown in Table 1.
[0046] Example 3 The third embodiment of this invention provides a method for fabricating a self-driven wide-bandgap perovskite ultraviolet detector based on a vapor-phase doping and low-pressure assisted annealing strategy, which mainly includes the following steps: C1, providing a glass substrate with an FTO conductive layer, and cleaning the FTO glass substrate.
[0047] Specifically, an FTO conductive glass substrate is provided, and the laser-etched FTO conductive substrate is ultrasonically cleaned sequentially with detergent, acetone, anhydrous ethanol, and deionized water for 25 minutes. The cleaned FTO glass is immediately dried in a clean environment with nitrogen gas flow and then treated in an ultraviolet ozone chamber for 35 minutes.
[0048] C2, TPPO-doped CsPbCl is prepared on the FTO conductive layer using a vapor deposition process. 3-x Br x Perovskite photosensitive film.
[0049] Specifically, a 200nm thick PbCl2 precursor layer is first deposited on the FTO conductive layer using a vacuum thermal evaporation process, followed by a 12nm TPPO doped layer, then a 110nm CsBr precursor layer, and finally a 30nm CsCl precursor layer, completing the TPPO-doped CsPbCl2 layer. 3-x Br x Thin film deposition was performed with the evaporation rates of PbCl2, CsBr, and CsCl layers controlled at 0.8 Å / s, and the evaporation rate of the TPPO doped layer controlled at 0.15 Å / s. The entire thin film deposition process was carried out at a pressure less than 5 × 10⁻⁶ Å / s.-4 The procedure is performed within a high-vacuum chamber.
[0050] C3, CsPbCl deposited in a tube furnace 3-x Br x The perovskite thin film is subjected to low-pressure assisted annealing.
[0051] Specifically, CsPbCl3 is processed in the tubular furnace equipped with a vacuum device. 3-x Br x The perovskite was annealed, with the internal pressure monitored by a barometer at 0.7 atm. The furnace temperature was set to 270°C, and the low-pressure annealing time was set to 30 min. This was applied to CsPbCl... 3-x Br x The nucleation and growth processes of thin films are favorablely regulated to ensure sufficient crystallization of the film and to facilitate the formation of TPPO in CsPbCl₂. 3-x Br x Uniform doping is achieved through thorough diffusion within the perovskite, and passivation of CsPbCl is achieved through the formation of P=O-Pb bonds between the two. 3-x Br x The purpose is to address halogen vacancy defects within and at grain boundaries of perovskites.
[0052] C4, TPPO-doped CsPbCl after annealing 3-x Br x Carbon electrodes are coated onto the perovskite photosensitive layer.
[0053] Specifically, in the prepared CsPbCl 3-x Br x A layer of commercial carbon paste, approximately 30 μm thick, is applied to the substrate using a coating knife. This paste is then heated on a 150°C hot plate for 12 minutes to dry, forming a stable carbon counter electrode. This completes the wide-bandgap CsPbCl... 3-x Br x Fabrication of the perovskite ultraviolet detector. Its performance test results are shown in Table 1.
[0054] Example 4 The third embodiment of this invention provides a method for fabricating a self-driven wide-bandgap perovskite ultraviolet detector based on a vapor-phase doping and low-pressure assisted annealing strategy, which mainly includes the following steps: D1 provides a glass substrate with an FTO conductive layer and cleans the FTO glass substrate.
[0055] Specifically, an FTO conductive glass substrate is provided, and the laser-etched FTO conductive substrate is ultrasonically cleaned sequentially with detergent, acetone, anhydrous ethanol, and deionized water for 25 minutes. The cleaned FTO glass is immediately dried in a clean environment with nitrogen gas flow and then treated in an ultraviolet ozone chamber for 35 minutes.
[0056] D2, TPPO-doped CsPbCl₂ is prepared on the FTO conductive layer using a vapor deposition process. 3-x Br x Perovskite photosensitive film.
[0057] Specifically, a 200 nm thick PbCl2 precursor layer is first deposited on the FTO conductive layer using a vacuum thermal evaporation process, followed by a 15 nm TPPO doped layer, then a 130 nm CsBr precursor layer, and finally a 10 nm CsCl precursor layer, completing the TPPO-doped CsPbCl2 layer. 3-x Br x Thin film deposition was performed with the evaporation rates of PbCl2, CsBr, and CsCl layers controlled at 0.8 Å / s, and the evaporation rate of the TPPO doped layer controlled at 0.2 Å / s. The entire thin film deposition process was carried out at a pressure less than 5 × 10⁻⁶ Å / s. -4 The procedure is performed within a high-vacuum chamber.
[0058] D3, CsPbCl deposited in a tube furnace 3-x Br x The perovskite thin film is subjected to low-pressure assisted annealing.
[0059] Specifically, CsPbCl3 is processed in the tubular furnace equipped with a vacuum device. 3-x Br x The perovskite was annealed, with the internal pressure monitored by a barometer at 0.7 atm. The furnace temperature was set to 280℃, and the low-pressure annealing time was set to 30 min. This was applied to CsPbCl... 3-x Br x The nucleation and growth processes of thin films are favorablely regulated to ensure sufficient crystallization of the film and to facilitate the formation of TPPO in CsPbCl₂. 3-x Br x Uniform doping is achieved through thorough diffusion within the perovskite, and passivation of CsPbCl is achieved through the formation of P=O-Pb bonds between the two. 3-x Br x The purpose is to address halogen vacancy defects within and at grain boundaries of perovskites.
[0060] D4, TPPO-doped CsPbCl after annealing 3-x Br x Carbon electrodes are coated onto the perovskite photosensitive layer.
[0061] Specifically, in the prepared CsPbCl 3-x Br x A layer of commercial carbon paste, approximately 30 μm thick, is applied to the substrate using a coating knife. This paste is then heated on a 150°C hot plate for 15 minutes to dry, forming a stable carbon counter electrode. This completes the wide-bandgap CsPbCl... 3-x Br x Fabrication of the perovskite ultraviolet detector. Its performance test results are shown in Table 1.
[0062] Table 1. Based on different TPPO doping concentrations and CsPbCl 3-x Br x Performance parameters of the ultraviolet detector with composition and post-annealing pressure under 375 nm ultraviolet light irradiation
[0063] For any points not covered above, existing technologies shall apply.
[0064] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for fabricating a self-driven wide-bandgap perovskite ultraviolet detector, characterized in that, The ultraviolet detector includes an FTO conductive glass substrate and TPPO-doped CsPbCl deposited on the FTO glass. 3-x Br x A perovskite polycrystalline thin film and a carbon electrode layer formed on the perovskite polycrystalline thin film; the perovskite polycrystalline thin film is formed by reacting a PbCl2 precursor layer, a TPPO doped layer, a CsBr layer and a CsCl layer deposited by thermal evaporation under high temperature annealing; wherein 0.5≤x≤1.
2. The preparation method according to claim 1, characterized in that, The thickness of the deposited PbCl2 layer is 190-200 nm, the thickness of the deposited CsBr layer is 70-140 nm, the thickness of the corresponding deposited CsCl layer is 0-70 nm, and the thickness of the TPPO doped layer is 3-18 nm.
3. The preparation method according to claim 1, characterized in that, First, a PbCl2 precursor layer of fixed thickness is deposited by thermal evaporation at a rate of 0.5–1 Å / s. Then, a TPPO doped layer is deposited by thermal evaporation at a rate of 0.1–0.2 Å / s. Next, a CsBr layer is deposited by thermal evaporation at a rate of 0.5–1 Å / s. Finally, a CsCl layer is deposited by thermal evaporation at a rate of 0.5–1 Å / s.
4. The preparation method according to claim 1, characterized in that, During high-temperature annealing, the pressure is set to 0.2~0.8 atm, the annealing temperature is set to 250~280 ℃, and the annealing time is 25~30 min.
5. The preparation method according to claim 1, characterized in that, The carbon electrode layer is a commercially available carbon paste, which is coated onto TPPO-doped CsPbCl using a blade coating process, resulting in a 20-30 μm thick carbon paste layer. 3-x Br x For the perovskite film surface, the carbon paste drying temperature is 120~150℃, and the drying time is 10~15min.
6. The preparation method according to claim 1, characterized in that, The deposition is all carried out in a high-vacuum sealed cavity, with an internal pressure not exceeding 5 × 10⁻⁶. -4 Pa.
7. The preparation method according to claim 1, characterized in that, The FTO conductive glass substrate was prepared by sequentially ultrasonically cleaning the laser-etched FTO conductive substrate with detergent, acetone, anhydrous ethanol, and deionized water for 20-25 minutes; the cleaned FTO glass was then dried in a clean environment with nitrogen gas flow and treated in an ultraviolet ozone chamber for 30-35 minutes.
8. A self-driven wide-bandgap perovskite ultraviolet detector prepared by the preparation method according to any one of claims 1-7.