Lead-free perovskite microstrip / silicon heterojunction photoelectric detector and preparation method thereof
By integrating lead-free perovskite CsAg2I3 material on silicon wafers, N-n isotype heterojunction structure is constructed, which solves the limitations of perovskite photodetectors in broad spectrum and high-speed detection, and achieves efficient and environmentally friendly photodetection effects.
Patent Information
- Application Number
- CN202311339302.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-17
- Publication Date
- 2025-04-22
AI Technical Summary
Existing perovskite photodetectors have limitations in broad spectrum and high-speed detection, especially in the near-infrared band, and traditional heterojunction detectors are unstable due to the containing organic cations and lead ions, resulting in environmental pollution.
Through the space-limited growth method, lead-free perovskite CsAg2I3 material is directly integrated on the silicon wafer to build an N-n isotype heterojunction structure to achieve wide spectrum and high-speed detection, and a low-cost and environmentally friendly preparation method is adopted.
It achieves improvements in wide spectrum and high-speed photoelectric detection performance, avoids leakage of lead elements and environmental pollution, and reduces preparation costs, which are suitable for the integration of high-density functional devices.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of photoelectric detectors, and in particular relates to a lead-free perovskite microstrip / silicon heterojunction photoelectric detector and a preparation method thereof. Background Art
[0002] Photodetectors can convert optical signals into electrical signals, which has important application value in industrial and scientific applications, such as optical remote sensing, space communication, target detection and autonomous driving. In recent years, metal halide perovskite materials have attracted extensive attention in the field of photodetectors due to their long electron-hole diffusion length, high mobility and excellent photovoltaic energy conversion ability. However, the optical band gap of perovskite limits its application in the field of wide-spectrum detection, especially in the near-infrared band. In addition, the response speed of perovskite photoelectric devices is usually limited. Combining perovskite materials with traditional inorganic optoelectronic semiconductor materials with mature processing technology to form heterojunction photodetectors is a promising approach. In the near-infrared light band, crystalline silicon-based photodetectors occupy the main market share, while silicon has a narrow band gap and has good compatibility with perovskite materials. To this end, considering the potential advantages of combining perovskite with silicon, perovskite can be integrated on silicon to achieve wide-spectrum and high-speed detection.
[0003] There have been reports of related research on integrating single-crystal halide perovskites on silicon wafers, such as existing heterojunction detectors such as CH3NH3PbBr3 / Si and MAPbBr3 / Si. However, due to the presence of organic cations and lead ions in the structure, the photoelectric detection device is unstable, resulting in the leakage of lead elements and facing environmental pollution and other problems. In addition, high integration density is one of the prerequisites for the next generation of electronic and optoelectronic systems, in which device units are usually arranged horizontally. Growing semiconductor nanobelts in the substrate plane can achieve large-scale horizontal distribution of one-dimensional structures, which is conducive to the efficient integration of high-density functional devices. To solve the above problems, the present invention proposes a lead-free perovskite microstrip / silicon heterojunction photodetector and a preparation method thereof. The one-dimensional lead-free perovskite CsAg2I3 is directly integrated on a silicon wafer by a spatially confined growth method to achieve wide spectrum and high-speed detection. In addition, the heterostructure proposed in the present invention has low preparation cost, simple process, and green environmental protection, and has great potential in promotion and application. Summary of the invention
[0004] In response to the improvement needs reported in existing research, the present invention improves the photoelectric detection performance by directly integrating lead-free perovskite on a silicon wafer and constructing a Nn isotype heterojunction structure, thereby achieving the purpose of wide spectrum and high-speed detection. The one-dimensional lead-free perovskite CsAg2I3 material is non-toxic and stable, and the heterojunction device formed by it and traditional silicon-based materials has high application potential in the field of photoelectric detection.
[0005] In order to achieve the above object, the technical solution adopted by the present invention is:
[0006] Provided is a lead-free perovskite microstrip / silicon heterojunction photodetector, whose device structure is Au / CsAg2I3 / n-Si / EGaIn.
[0007] A method for preparing a lead-free perovskite microstrip / silicon heterojunction photodetector comprises the following steps:
[0008] 1. Preparation of perovskite precursor solution:
[0009] Cesium iodide, silver iodide, dimethyl sulfoxide and dimethylformamide were mixed in a certain mass ratio and stirred evenly on a stirring heating table. The stirring temperature was 60-80 o C, stirring time is 240-480 minutes. After cooling, filter through a filter to obtain a perovskite precursor solution.
[0010] 2. Preparation of perovskite / silicon heterojunction:
[0011] Use acetone, ethanol and deionized water to clean the single crystal n-Si substrate and quartz wafer in turn, and then use a nitrogen gun to dry. Place the cleaned n-Si substrate on the heating table, take a certain amount of precursor solution and drop it on the center of the n-Si substrate, then cover the cleaned quartz wafer and place a weight on the quartz wafer, start the heating table and let it stand for heating. The heating temperature is 60-80 o C, the heating time is 240-480 minutes. After cooling, the n-Si substrate is peeled off with the aid of tape, and placed on a heating table for annealing to remove the remaining solvent to obtain a perovskite microstrip / silicon heterojunction structure.
[0012] 3. Electrode deposition of heterojunction devices:
[0013] The heterojunction structure is placed in the chamber of the evaporator, and a metal electrode is deposited on the surface of the perovskite microstrip using a mask of a certain specification. Then, the liquid alloy electrode is coated on the n-Si substrate area.
[0014] Furthermore, in step 1, the ratio of the organic solvents dimethyl sulfoxide and dimethylformamide is 1:4.
[0015] Furthermore, in step 2, the n-Si substrate is an n-type
[111] single crystal silicon wafer with a thickness of 200-500 μm and a resistivity of 10-50 Ω / cm.
[0016] Furthermore, in step 2, the weight of the weight is 0-50 g.
[0017] Further, the annealing temperature in step 2 is 60-80 o C, annealing time is 10-20 minutes.
[0018] Furthermore, the perovskite microstrip has a length of 0.8-1.3 mm, a width of 20-50 μm, and a thickness of 500-800 μm.
[0019] Furthermore, in step 3, the metal electrode is an Au electrode or an Ag electrode, and the thickness of the metal electrode is 80-200 nm.
[0020] Furthermore, the liquid alloy in step 3 is an In / Ga alloy electrode (EGaIn).
[0021] In summary, the beneficial effects of the present invention are as follows:
[0022] 1. The present invention provides a lead-free perovskite microstrip / silicon heterojunction photodetector and a preparation method thereof, wherein a CsAg2I3 microstrip is directly integrated on a silicon wafer, and a Nn isotype heterojunction structure is constructed to improve the photodetection performance, thereby achieving the purpose of wide spectrum and high-speed detection. The problem of the detection range of perovskite-based photodetectors being limited by the band gap is improved, and the response speed of lead-free perovskite-based photodetectors is improved.
[0023] 2. This technical solution grows semiconductor microstrips within the silicon wafer plane, which can achieve large-scale horizontal distribution of low-dimensional structures, which is conducive to the efficient integration of high-density functional devices.
[0024] 3. The perovskite / silicon heterojunction prepared by this technical solution has no damaging effect on silicon wafers and is suitable for most traditional silicon-based material CMOS processes.
[0025] 4. The process conditions of this technical solution are easy to implement, low cost, environmentally friendly and have high output. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The present invention will be described by way of example with reference to the accompanying drawings, in which:
[0027] Figure 1 It is a schematic diagram of the structure of the lead-free perovskite microstrip / silicon heterojunction photodetector of the present invention.
[0028] Figure 2 The lead-free perovskite microstrip / silicon heterojunction photodetector of the present invention is respectively in the absence of light and at a wavelength of 365nm and an intensity of 14.09mW / cm 2 Time-current characteristic curve under light illumination.
[0029] Figure 3 It is the responsivity of the lead-free perovskite microstrip / silicon heterojunction photodetector of the present invention at wavelengths of 254nm, 365nm, 405nm, 520nm, 635nm and 980nm.
[0030] Figure 4The time-current characteristic curve of the lead-free perovskite microstrip / silicon heterojunction photodetector of the present invention under light with a wavelength of 635 nm and a frequency of 100 Hz. DETAILED DESCRIPTION
[0031] The present invention will be described in detail below in conjunction with the accompanying drawings.
[0032] Example 1:
[0033] a) Weigh 0.650 g of cesium iodide and 0.952 g of silver iodide in a molar ratio of 1:1, place them in a beaker, mix them, and add a mixed organic solvent of dimethyl sulfoxide and dimethylformamide in a volume ratio of 1:4. o C and stirred for 8 h. Filtered with a 0.22 μm filter to obtain a precursor solution.
[0034] b) Take a 1cm×1cm n-Si sheet with a resistivity of 20Ω / cm and a thickness of 250μm and a 2cm×2cm quartz sheet, respectively, and ultrasonically clean them with acetone, ethanol and deionized water for 20 minutes, then blow dry with nitrogen. Place the cleaned n-Si on the heating table, take 40μL of the precursor solution obtained in step a) and drop it to the center of the n-Si sheet and cover the cleaned quartz sheet. Place a weight of 10g on the quartz sheet and heat the heating table to 70 o After cooling, use tape to assist in peeling the n-Si sheet, and place the peeled n-Si sheet on the heating table at 70 o C annealing for 15 min to obtain a perovskite microstrip / silicon heterojunction.
[0035] c) Under the assistance of an optical microscope, the heterojunction obtained in step b) is covered with a mask, and an Ag electrode with a thickness of 80 nm is deposited on the perovskite microstrip by a vacuum evaporator as the contact electrode of the perovskite CsAg2I3 microstrip. The vacuum degree is 8Í10 -3 Pa or less. Then, with the help of an optical microscope, the n-Si region is coated with EGaIn liquid alloy as the n-Si sheet electrode. This completes the preparation of the lead-free perovskite microstrip / silicon heterojunction photodetector.
[0036] Example 2:
[0037] a) Weigh 0.650 g of cesium iodide and 0.952 g of silver iodide in a molar ratio of 1:1, place them in a beaker, mix them, and add a mixed organic solvent of dimethyl sulfoxide and dimethylformamide in a volume ratio of 1:4. o C and stirred for 8 h. Filtered with a 0.22 μm filter to obtain a precursor solution.
[0038] b) Take a 1cm×1cm n-Si sheet with a resistivity of 20Ω / cm and a thickness of 250μm and a 2cm×2cm quartz sheet, respectively, and ultrasonically clean them with acetone, ethanol and deionized water for 20 minutes, then blow dry with nitrogen. Place the cleaned n-Si on the heating table, take 40μL of the precursor solution obtained in step a) and drop it to the center of the n-Si sheet and cover the cleaned quartz sheet. Place a 50g weight on the quartz sheet and heat the heating table to 70 o After cooling, use tape to assist in peeling the n-Si sheet, and place the peeled n-Si sheet on the heating table at 70 o C annealing for 15 min to obtain a perovskite microstrip / silicon heterojunction.
[0039] c) Under the assistance of an optical microscope, the heterojunction obtained in step b) is covered with a mask, and an Ag electrode with a thickness of 80 nm is deposited on the perovskite microstrip by a vacuum evaporator as the contact electrode of the perovskite CsAg2I3 microstrip. The vacuum degree is 8Í10 -3 Pa or less. Then, with the help of an optical microscope, the n-Si region is coated with EGaIn liquid alloy as the n-Si sheet electrode. This completes the preparation of the lead-free perovskite microstrip / silicon heterojunction photodetector.
[0040] Example 3:
[0041] a) Weigh 0.650 g of cesium iodide and 0.952 g of silver iodide in a molar ratio of 1:1, place them in a beaker, mix them, and add a mixed organic solvent of dimethyl sulfoxide and dimethylformamide in a volume ratio of 1:4. o C and stirred for 8 h. Filtered with a 0.22 μm filter to obtain a precursor solution.
[0042] b) Take a 1cm×1cm n-Si sheet with a resistivity of 20Ω / cm and a thickness of 250μm and a 2cm×2cm quartz sheet, respectively, and ultrasonically clean them with acetone, ethanol and deionized water for 20min, then blow dry with nitrogen. Put the cleaned n-Si on the heating table, take 40μL of the precursor solution obtained in step a) and drop it to the center of the n-Si sheet and cover the cleaned quartz sheet, then heat the heating table to 70 o After cooling, use tape to assist in peeling the n-Si sheet, and place the peeled n-Si sheet on the heating table at 70 o C annealing for 15 min to obtain a perovskite microstrip / silicon heterojunction.
[0043] c) Under the assistance of an optical microscope, the heterojunction obtained in step b) is covered with a mask, and an Ag electrode with a thickness of 80 nm is deposited on the perovskite microstrip by a vacuum evaporator as the contact electrode of the perovskite CsAg2I3 microstrip. The vacuum degree is 8Í10 -3 Pa or less. Then, with the help of an optical microscope, the n-Si region is coated with EGaIn liquid alloy as the n-Si sheet electrode. This completes the preparation of the lead-free perovskite microstrip / silicon heterojunction photodetector.
[0044] The above embodiments are only used to explain the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of protection of the present application. It should be pointed out that for ordinary technicians in this field, any modifications and changes made to the present invention without departing from the technical solution concept of the present application belong to the scope of protection of the present application.
Claims
1. A lead-free perovskite microstrip / silicon heterojunction photodetector, characterized in that: The heterojunction structure is CsAg2I3 / n-Si.
2. A lead-free perovskite microstrip / silicon heterojunction photodetector as claimed in claim 1, characterized in that: The device structure is metal electrode / CsAg2I3 / n-Si / alloy electrode.
3. A lead-free perovskite microstrip / silicon heterojunction photodetector as claimed in claim 1, characterized in that: The microstrip has a one-dimensional perovskite structure.
4. A lead-free perovskite microstrip / silicon heterojunction photodetector as claimed in claim 1, characterized in that: The device is used for photoelectric detection in the ultraviolet-visible-near infrared band.
5. A method for preparing a lead-free perovskite microstrip / silicon heterojunction photodetector, characterized in that: The following steps are involved: (1) according to the stoichiometric ratio of the chemical formula of CsAg2I3, cesium iodide powder and silver iodide powder are weighed respectively, placed in a beaker, mixed, and dimethyl sulfoxide and dimethylformamide are added, stirred and heated, and the resulting solution after filtering is the precursor solution; (2) placing a clean silicon wafer on a heating table, taking an appropriate amount of the precursor solution obtained in step (1) and dropping it on the silicon wafer, covering it with a clean quartz wafer, and then placing a weight on the quartz wafer, and leaving it on the heating table to heat; (3) The silicon wafer in step (2) is peeled off with the aid of tape, and a perovskite microstrip / silicon heterojunction is obtained after annealing. A lead-free perovskite microstrip / silicon heterojunction photodetector is obtained after evaporating a metal electrode and coating it with a liquid alloy electrode.