WO2024098487A1 - All-inorganic perovskite photosensitive layer, and preparation method therefor and use thereof - Google Patents

All-inorganic perovskite photosensitive layer, and preparation method therefor and use thereof Download PDF

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WO2024098487A1
WO2024098487A1 PCT/CN2022/137081 CN2022137081W WO2024098487A1 WO 2024098487 A1 WO2024098487 A1 WO 2024098487A1 CN 2022137081 W CN2022137081 W CN 2022137081W WO 2024098487 A1 WO2024098487 A1 WO 2024098487A1
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perovskite
photosensitive layer
inorganic
preparation
ray detector
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French (fr)
Chinese (zh)
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刘延亮
喻学锋
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深圳先进技术研究院
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    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/66—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing germanium, tin or lead
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/032—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
    • H01L31/115—Devices sensitive to very short wavelength, e.g. X-rays, gamma-rays or corpuscular radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof

Definitions

  • the present invention belongs to the technical field of optoelectronic materials, and specifically relates to an all-inorganic perovskite photosensitive layer and a preparation method and application thereof.
  • X-ray detectors are widely used in imaging, industrial material testing, nuclear power plant safety, national defense science and technology, medicine, etc.
  • halide perovskite materials have attracted much attention in the field of X-ray detection research.
  • perovskite materials With their high X-ray absorption coefficient, large carrier diffusion distance, high bulk resistivity, excellent material plasticity, excellent liquid phase process compatibility, flexible device interface adjustability and other excellent properties, perovskite materials have shown unparalleled outstanding potential in achieving X-ray low radiation dose imaging, high-resolution imaging, fast dynamic imaging, flexible imaging, etc., and have quickly become one of the preferred materials for the next generation of X-ray detection and imaging systems.
  • CN112071989A discloses an X-ray detector based on a perovskite single crystal and a preparation method thereof, wherein the X-ray detector is composed of a perovskite single crystal and Au and Ga electrodes located on both sides of the perovskite single crystal.
  • the preparation method is as follows: a FAPbBr 3 perovskite single crystal is grown by an improved slow heating method, seed crystal grains are first prepared in a perovskite single crystal growth solution, and then seed crystals with regular shapes are selected and transferred to a newly configured solution for continued growth until the crystal has a suitable size, thereby completing the single crystal preparation.
  • CN112142100A discloses a perovskite polycrystalline thin slice and its preparation method and application.
  • a perovskite powder APbX 3 is prepared by a solution method through the reaction of PbX 2 powder and AX, and then the perovskite powder is hot-pressed in situ under high temperature and high pressure to prepare a perovskite polycrystalline thin slice;
  • A is Cs, CH 2 NH 3 or CH(NH 3 ) 2
  • X is a halogen.
  • single crystals have fewer defects and lower detection efficiency, but cannot be grown in a large area by a solution method; polycrystalline pressed sheets can obtain a large area of perovskite layer, but the preparation process requires high temperature and high pressure, which will cause the perovskite material to decompose and introduce crystal defects; in addition, both single crystals and polycrystalline pressed sheets cannot be directly integrated with substrates and pixel chips, which greatly limits their application in X-ray detection imaging.
  • the liquid phase method is a common method for in-situ growth and preparation of perovskite thin films (several hundred nanometers), which is commonly used in perovskite solar cells and light-emitting diodes.
  • the following steps are: first, all the precursor materials of the perovskite are dissolved in organic solvents such as N,N -dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and ⁇ -butyrolactone (GBL), and then the perovskite thin film is prepared by spin coating, scraping, spraying, inkjet printing, slit coating, etc.
  • organic solvents such as N,N -dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and ⁇ -butyrolactone (GBL)
  • CN109920918A discloses a perovskite photodetector, whose structure from bottom to top is substrate, conductive anode, hole transport layer, perovskite photoactive layer, composite electron transport layer, hole blocking layer and metal cathode; wherein the composite electron transport layer is composed of PCBM and gelatin, and the material of the perovskite photoactive layer is MAPbI 3 with a thickness of 300-700 nm, which is prepared by spin coating the perovskite solution and annealing.
  • perovskite films by liquid phase method are mild, and it is expected to be integrated with multi-pixel chips (TFT, CMOS); however, high-energy X/ ⁇ -rays have strong energy, and thick perovskite films (several hundred microns) are required to fully absorb and convert them.
  • TFT multi-pixel chips
  • CMOS complementary metal-oxide-semiconductor
  • solubility of perovskite precursor materials in solutions DMF, GBL, DMSO
  • it is still very challenging to prepare large-area dense perovskite thick films on substrates by liquid phase method and there is still a lack of preparation methods with strong operability and simple process.
  • the commonly used perovskite thick film materials are organic-inorganic hybrid perovskite materials (such as MAPbI 3 , FAPbI 3 , FAPbBr 3 , etc.), which have poor environmental humidity stability and poor thermal stability, which seriously affects the stability of detection devices.
  • organic-inorganic hybrid perovskite materials such as MAPbI 3 , FAPbI 3 , FAPbBr 3 , etc.
  • the object of the present invention is to provide an all-inorganic perovskite photosensitive layer and a preparation method and application thereof.
  • the all-inorganic perovskite photosensitive layer is prepared by a low-temperature liquid phase method including screen printing, which has a simple process and strong operability, and realizes large-area preparation of perovskite thick films.
  • the obtained all-inorganic perovskite photosensitive layer is dense, uniform, and has high flatness and good environmental stability, so that the X-ray detector containing it has excellent stability and sensitivity.
  • the present invention provides a method for preparing an all-inorganic perovskite photosensitive layer, wherein the thickness of the all-inorganic perovskite photosensitive layer is ⁇ 90 ⁇ m; the preparation method comprises the following steps:
  • A is Cs, Bi or Rb
  • B is Pb, Sn or Ge
  • X and Y are each independently a halogen
  • step (1) The perovskite material ABXY2 obtained in step (1) is mixed with an organic solvent to obtain a perovskite precursor slurry;
  • step (3) The perovskite precursor slurry obtained in step (2) is formed into a coating by screen printing, and the coating is annealed to obtain the all-inorganic perovskite photosensitive layer.
  • the inorganic halide AX and BY 2 are first ground to obtain an all-inorganic perovskite material ABXY 2 , which is then uniformly mixed with an organic solvent to obtain an all-inorganic perovskite precursor slurry; the perovskite precursor slurry is formed into a coating by screen printing, and after annealing and in-situ growth, a large-area, flat, dense and uniform all-inorganic perovskite photosensitive layer is obtained.
  • the preparation method of the present invention is a low-temperature liquid phase process with mild conditions, simple process and strong operability.
  • the perovskite has high crystallinity, few crystal defects, excellent environmental humidity stability and thermal stability, and can fully absorb and convert high-energy X/ ⁇ rays, thereby reducing the dark current of the X-ray detector containing it, improving the aging stability and carrier transport performance of the device, thereby effectively improving the sensitivity and stability of the X-ray detector.
  • the A is Cs
  • the inorganic halide AX is CsX
  • the B is Pb
  • the inorganic halide BY 2 is PbY 2 .
  • X and Y are each independently Cl, Br or I, more preferably Cl or Br.
  • the inorganic halide AX is CsCl and/or CsBr.
  • the inorganic halide BY 2 is PbCl 2 and/or PbBr 2 .
  • the perovskite material ABXY 2 in step (1) includes CsPbCl 3 , CsPbBr 3 , CsPbClBr 2 or CsPbCl 2 Br.
  • the molar ratio of the inorganic halide AX to the inorganic halide BY 2 is 1:(0.5-2), for example, it can be 1:0.6, 1:0.8, 1:1, 1:1.1, 1:1.3, 1:1.5, 1:1.7 or 1:1.9, etc.
  • the grinding in step (1) is mechanical grinding.
  • the grinding in step (1) is dry grinding, and no solvent is required to be added during the grinding process.
  • the grinding method in step (1) is ball milling.
  • the ball-to-material ratio of the ball mill is 1:(1-5), for example, it can be 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, 1:4.2, 1:4.5 or 1:4.8, etc.
  • the ball-to-material ratio is the mass ratio of the ball milling balls to the raw materials (inorganic halide AX and inorganic halide BY 2 ).
  • the rotation speed of the ball mill is 200-1000 rpm, for example, it can be 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or 900 rpm.
  • the ball milling time is 0.5-6 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h or 5.5 h.
  • the ball milling is carried out in a planetary ball mill.
  • the organic solvent in step (2) comprises any one or a combination of at least two of dimethyl sulfoxide (DMSO), N,N -dimethylformamide (DMF), N,N -dimethylacetamide (DMAC) or ⁇ -butyrolactone (GBL), and more preferably a combination of dimethyl sulfoxide and N,N -dimethylformamide.
  • DMSO dimethyl sulfoxide
  • DMF N,N -dimethylformamide
  • DMAC N,N -dimethylacetamide
  • GBL ⁇ -butyrolactone
  • the volume ratio of dimethyl sulfoxide to N,N -dimethylformamide is (0.5-5):1, for example, it can be 0.6:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1 or 4.5:1, etc.
  • the organic solvent in step (2) is a combination of DMSO and DMF; the specific organic solvent is conducive to the regrowth of the perovskite material ABXY2 microcrystals, thereby obtaining high-quality all-inorganic perovskite; and the increase in the DMSO content in the organic solvent can further enhance the regrowth effect of the perovskite material ABXY2 microcrystals; when the volume ratio of DMSO to DMF is 1:1, the obtained perovskite material ABXY2 microcrystals (such as CsPbBr3 microcrystals) have obvious block shape.
  • the mass ratio of the perovskite material ABXY2 to the organic solvent is (3-5):1, for example, it can be 3.1:1, 3.3:1, 3.5:1, 3.7:1, 3.9:1, 4:1, 4.1:1, 4.3:1, 4.5:1, 4.7:1 or 4.9:1, etc.
  • the mixed material in step (2) further includes a viscosity regulator.
  • the viscosity modifier comprises terpineol and/or cellulose.
  • the mixed material in step (2) includes pinene alcohol and/or cellulose, the pinene alcohol serves as an anti-solvent, and the cellulose serves as a thickener, which helps to adjust the viscosity of the perovskite precursor slurry.
  • the cellulose comprises ethyl cellulose.
  • the volume ratio of terpineol to organic solvent is 1:(4-8), for example, it can be 1:4.2, 1:4.5, 1:4.8, 1:5, 1:5.2, 1:5.5, 1:5.8, 1:6, 1:6.2, 1:6.5, 1:6.8, 1:7, 1:7.2, 1:7.5 or 1:7.8, etc.
  • the mass ratio of cellulose to perovskite material ABXY2 is 1:(10-20), for example, it can be 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18 or 1:19, etc.
  • step (2) further includes a grinding step after the mixing.
  • the grinding time is 0.5-3 h, for example, 0.8 h, 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h, 2.2 h, 2.5 h or 2.8 h, etc.; the grinding process helps to form a more evenly dispersed perovskite precursor slurry.
  • the solid content of the perovskite precursor slurry in step (2) is 70-90%, for example, it can be 71%, 73%, 75%, 77%, 79%, 80%, 81%, 83%, 85%, 87% or 89%.
  • step (3) forms the coating on the conductive substrate by screen printing.
  • the conductive substrate includes an ITO conductive substrate, a FTO conductive substrate, a TFT pixel chip or a CMOS pixel chip.
  • the number of screen printing in step (3) is 1-5 times, for example, 2 times, 3 times or 4 times.
  • the aperture of the screen printing in step (3) is 200-500 mesh, for example, 220 mesh, 250 mesh, 280 mesh, 300 mesh, 320 mesh, 350 mesh, 380 mesh, 400 mesh, 420 mesh, 450 mesh or 480 mesh.
  • the viscosity of the perovskite precursor slurry, the number of screen printing, and the design and compounding of the screen aperture are adjusted to obtain the all-inorganic perovskite photosensitive layer of different thicknesses for absorbing X-rays of different energies.
  • the annealing temperature in step (3) is 80-150°C, for example, it can be 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C or 145°C, etc.
  • the annealing time in step (3) is 0.5-2 h, for example, it can be 0.6 h, 0.8 h, 1 h, 1.1 h, 1.3 h, 1.5 h, 1.7 h or 1.9 h.
  • the annealing in step (3) includes a first stage annealing and a second stage annealing performed sequentially, and the temperature of the first stage annealing is less than the temperature of the second stage annealing.
  • the temperature of the first stage annealing is 80-120°C, for example, it can be 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, 100°C, 102°C, 105°C, 108°C, 110°C, 112°C, 115°C or 118°C, etc.
  • the first stage annealing time is 10-40 min, for example, 15 min, 20 min, 25 min, 30 min or 35 min.
  • the temperature of the second stage annealing is 125-150°C, for example, it can be 128°C, 130°C, 132°C, 135°C, 138°C, 140°C, 142°C, 145°C or 148°C.
  • the second stage annealing time is 20-80 min, for example, it can be 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min or 75 min, etc.
  • step (3) by designing and precisely controlling the process parameters of annealing, including the control of temperature, heating rate, time, gradient heating and other conditions, the solvent is fully volatilized, and the crystal growth of the perovskite thick film can be effectively regulated, the crystallinity of the perovskite is improved, defects are modified, and the photoelectric properties of the material are improved, so that perovskite crystals with high crystallinity and low defects are obtained, thereby obtaining the high-quality all-inorganic perovskite photosensitive layer.
  • the thickness of the all-inorganic perovskite photosensitive layer is ⁇ 90 ⁇ m, and the preparation method specifically comprises the following steps:
  • the perovskite material ABXY2 obtained in step (1) is mixed with an organic solvent and ground to obtain a perovskite precursor slurry;
  • the organic solvent comprises dimethyl sulfoxide and N,N -dimethylformamide in a volume ratio of (0.5-5):1;
  • the mass ratio of the perovskite material ABXY2 to the organic solvent is (3-5):1;
  • the perovskite precursor slurry obtained in step (2) is formed into a coating by screen printing, and the coating is subjected to a first stage annealing and a second stage annealing in sequence to obtain the all-inorganic perovskite photosensitive layer; the temperature of the first stage annealing is 80-120°C and the time is 10-40 min; the temperature of the second stage annealing is 125-150°C and the time is 20-80 min.
  • the present invention provides an all-inorganic perovskite photosensitive layer, which is prepared by the preparation method described in the first aspect.
  • the thickness of the all-inorganic perovskite photosensitive layer is 90-500 ⁇ m, for example, 100 ⁇ m, 120 ⁇ m, 150 ⁇ m, 180 ⁇ m, 200 ⁇ m, 220 ⁇ m, 250 ⁇ m, 280 ⁇ m, 300 ⁇ m, 320 ⁇ m, 350 ⁇ m, 380 ⁇ m, 400 ⁇ m, 420 ⁇ m, 450 ⁇ m or 480 ⁇ m, etc.
  • the present invention provides a use of the all-inorganic perovskite photosensitive layer as described in the second aspect in a perovskite cell or a perovskite detection device.
  • the perovskite detection device comprises an X/ ⁇ -ray detector.
  • the perovskite detection device is an X-ray detector.
  • the present invention provides an X-ray detector, comprising a conductive substrate, a perovskite photosensitive layer, a transmission layer and a back electrode; the perovskite photosensitive layer is the all-inorganic perovskite photosensitive layer described in the second aspect.
  • the X-ray detector is a P-I-N type or N-I-P type photodiode device structure including an electrode material, the all-inorganic perovskite photosensitive layer and a transmission layer.
  • the conductive substrate includes an ITO conductive substrate, a FTO conductive substrate, a TFT pixel chip or a CMOS pixel chip.
  • the conductive substrate comprises an ITO conductive substrate, which comprises an ITO conductive layer and a substrate layer, and the ITO conductive layer is located on a side close to the perovskite photosensitive layer.
  • the material of the transport layer includes a commonly used transport layer material in the art, illustratively including but not limited to: fullerene (C60), fullerene derivatives (such as PCBM), BCP, polythiophenes (such as PEDOT:PSS, P3HT), polyanilines (such as poly-TPD, PTAA), nickel oxide (NiO X ), aromatic amine compounds (such as TAPC), titanium oxide (TiO X ), molybdenum oxide (MoO X , such as MoO 3 ), V 2 O 5 or WO 3 , etc.
  • a commonly used transport layer material in the art illustratively including but not limited to: fullerene (C60), fullerene derivatives (such as PCBM), BCP, polythiophenes (such as PEDOT:PSS, P3HT), polyanilines (such as poly-TPD, PTAA), nickel oxide (NiO X ), aromatic amine compounds (such as TAPC), titanium oxide (
  • the transmission layer is a single-layer structure or a multi-layer structure.
  • the transport layer is an electron transport layer.
  • the X-ray detector comprises a conductive substrate, the all-inorganic perovskite photosensitive layer, an electron transport layer and a back electrode which are arranged in sequence.
  • the electron transport layer comprises a fullerene derivative electron transport layer, and more preferably a PCBM electron transport layer.
  • the thickness of the electron transport layer is 1-100 nm, for example, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm or 90 nm.
  • the back electrode comprises a metal electrode or a carbon electrode.
  • the back electrode is a metal electrode
  • the material includes any one of Cu, Ag, Au, Al, and Cr, or a combination of at least two thereof, and more preferably includes an Au electrode.
  • the thickness of the back electrode is 50-200 nm, for example, 60 nm, 80 nm, 100 nm, 110 nm, 130 nm, 150 nm, 170 nm or 190 nm.
  • the all-inorganic perovskite photosensitive layer prepared by the present invention has the characteristics of large area, density, uniformity and flatness.
  • the perovskite has high crystallinity, few defects and excellent crystal quality, thereby effectively reducing the dark current of the X-ray detector containing the all-inorganic perovskite photosensitive layer and improving the aging stability and carrier transport performance of the device.
  • the thickness of the all-inorganic perovskite (CsPbBr 3 ) photosensitive layer is 300 ⁇ m
  • the dark current of the X-ray detector is 10 -11 -10 -9 A ⁇ mm -2
  • the corresponding photocurrent under bias is increased to 10 -9 -10 -7 A ⁇ mm -2 , which is more than 100 times higher
  • the sensitivity of the X-ray detector at 20 V/mm is 1547 ⁇ C ⁇ Gy air -1 ⁇ cm -2
  • the sensitivity at 40 V/mm is 4334 ⁇ C ⁇ Gy air -1 ⁇ cm -2
  • the sensitivity at 60 V/mm is 7266 ⁇ C ⁇ Gy air -1 ⁇ cm -2
  • the sensitivity at 80 V/mm is 9341 ⁇ C ⁇ Gy air -1 ⁇ cm -2
  • the minimum detectable X-ray dose of the X-ray detector is 588 n Gy air ⁇ s -1 At this time, the signal
  • the present invention provides a method for preparing the X-ray detector according to the fourth aspect, the preparation method comprising:
  • the all-inorganic perovskite photosensitive layer is prepared on the conductive layer (such as ITO conductive layer) of the conductive substrate by using the preparation method described in the first aspect;
  • the method of coating the electron transport layer material comprises spin coating, ie, spin coating a solution containing the electron transport layer material.
  • the concentration of the electron transport layer material in the solution is 10-30 mg/mL, for example, 12 mg/mL, 15 mg/mL, 18 mg/mL, 20 mg/mL, 22 mg/mL, 25 mg/mL or 28 mg/mL.
  • the solvent of the solution is any one of chlorobenzene, chloroform, o-dichlorobenzene or o-xylene, or a combination of at least two of them.
  • the rotation speed of the spin coating is 2000-6000 rpm, for example, it can be 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, 5000 rpm or 5500 rpm, etc.
  • the spin coating time is 10-60 s, for example, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s or 55 s, etc.
  • the drying temperature is 80-120°C, for example, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or 115°C.
  • the drying time is 2-20 min, for example, 3 min, 5 min, 7 min, 9 min, 10 min, 12 min, 15 min or 18 min, etc.
  • the present invention has the following beneficial effects:
  • the preparation method of the all-inorganic perovskite photosensitive layer provided by the present invention is a low-temperature liquid phase process including screen printing, which has mild conditions, simple process, strong operability, and can directly grow a thick perovskite film in situ on a conductive substrate or a pixel chip, thereby achieving good bonding integration between the material and the conductive substrate/pixel chip. It has the potential for large-scale preparation and provides a process basis for detection imaging.
  • the all-inorganic perovskite photosensitive layer obtained by the preparation method has the characteristics of large area, dense uniformity and high flatness.
  • the perovskite has high crystallinity, few crystal defects, good crystal quality, excellent environmental humidity stability and thermal stability, and can fully absorb and convert high-energy X/ ⁇ rays.
  • the X-ray detector containing the all-inorganic perovskite photosensitive layer has excellent photoelectric performance and stability, its dark current is reduced, and the aging stability and carrier transport performance of the device are effectively improved.
  • the X-ray detector has obvious improvements in sensitivity and stability, and the signal-to-noise ratio is reduced, and has good application prospects.
  • FIG1 is a process flow chart of step (3) in Example 1, wherein: 1-perovskite precursor slurry, 2-scraper, 3-screen, 4-screen frame, 5-substrate, 6-printing platform;
  • FIG2 is an optical image of the all-inorganic perovskite photosensitive layer described in Example 1;
  • FIG3 is a SEM surface morphology of the all-inorganic perovskite photosensitive layer described in Example 1;
  • FIG4 is a SEM cross-sectional morphology of the all-inorganic perovskite photosensitive layer described in Example 1;
  • FIG5 is a schematic diagram of the structure of the X-ray detector described in Example 2, wherein 10 is a conductive substrate, 20 is a perovskite photosensitive layer, 30 is an electron transport layer, and 40 is a back electrode;
  • FIG6 is an I-V curve diagram of the X-ray detector described in Example 2.
  • FIG7 is a sensitivity test diagram of the X-ray detector of Example 2 under different electric field strengths
  • FIG8 is a result diagram of the minimum detectable X-ray dose of the X-ray detector described in Example 2.
  • the raw materials and reagents involved are all commercially available products, such as terpineol (Aladdin, CAS No. 8000-41-7); ethyl cellulose (Aladdin, CAS No. 9004-57-3).
  • CsBr and PbBr2 were mixed evenly in a molar ratio of 1:1, and then placed in an agate ball mill, and planetary ball milled to obtain CsPbBr3 perovskite powder; the ball-to-material ratio of the ball mill was 1:5, the rotation speed was 200 rpm, and the time was 1 h;
  • step (2) The CsPbBr3 perovskite powder obtained in step (1) is placed in a mortar, and an organic solvent (a mixed solvent of DMF and DMSO in a volume ratio of 1:1) is added, and the mass ratio of CsPbBr3 perovskite powder to the organic solvent is 4:1; then pineneol (the volume ratio of pineneol to the organic solvent is 1:6) is added as an anti-solvent, and ethyl cellulose (the mass ratio of ethyl cellulose to CsPbBr3 perovskite powder is 1:15) is added as a thickener, and the mixture is ground for 1 h and mixed evenly to obtain a perovskite precursor slurry with a solid content of 80%;
  • an organic solvent a mixed solvent of DMF and DMSO in a volume ratio of 1:1
  • pineneol the volume ratio of pineneol to the organic solvent is 1:6
  • ethyl cellulose the mass ratio of eth
  • step (3) Screen printing and annealing the perovskite precursor slurry obtained in step (2) to form the all-inorganic perovskite photosensitive layer;
  • step (3) The process flow chart of step (3) is shown in Figure 1, wherein 1 is perovskite precursor slurry, 2 is a scraper, 3 is a screen plate, 4 is a screen frame, 5 is a substrate, and 6 is a printing table; the screen printing is performed 3 times, the screen aperture is 300 mesh, and a coating is formed; the coating is first annealed at 100°C for 10 min, the solvent gradually evaporates, and the perovskite crystals grow, and then annealed at 150°C for 30 min to obtain the all-inorganic perovskite photosensitive layer with a thickness of 300 ⁇ m.
  • the optical image of the all-inorganic perovskite photosensitive layer obtained by the preparation method provided in this embodiment is shown in Figure 2; the morphology of the all-inorganic perovskite photosensitive layer was tested by scanning electron microscopy (SEM, Zeiss Gemini SEM 300), and the SEM surface morphology of the all-inorganic perovskite photosensitive layer in Example 1 is shown in Figure 3, and the SEM cross-sectional morphology is shown in Figure 4.
  • SEM scanning electron microscopy
  • the preparation method can achieve large-area preparation of the all-inorganic perovskite photosensitive layer, and the surface of the obtained all-inorganic perovskite photosensitive layer is dense and flat, with good uniformity, and the cross-section also shows a relatively complete morphology, ensuring sufficient absorption and conversion of X-rays.
  • An X-ray detector the structure of which is shown in FIG5 , comprises a conductive substrate 10, a perovskite photosensitive layer 20, an electron transport layer 30 and a back electrode 40 arranged in sequence; wherein the conductive substrate 10 is an ITO conductive substrate (ITO conductive glass), the perovskite photosensitive layer 20 is an all-inorganic perovskite photosensitive layer (thickness 300 ⁇ m) obtained by the preparation method described in Example 1, the electron transport layer 30 is a PCBM electron transport layer (thickness 30 nm), and the back electrode 40 is an Au electrode with a thickness of 100 nm.
  • ITO conductive substrate ITO conductive glass
  • the perovskite photosensitive layer 20 is an all-inorganic perovskite photosensitive layer (thickness 300 ⁇ m) obtained by the preparation method described in Example 1
  • the electron transport layer 30 is a PCBM electron transport layer (thickness 30 nm)
  • the back electrode 40 is an Au electrode with a thickness of 100
  • the method for preparing the X-ray detector comprises the following steps:
  • step (3) Vacuum evaporating an Au electrode on the PCBM electron transport layer obtained in step (2) at a vacuum degree of 10 -6 mbar and an evaporation rate of 0.3 ⁇ /s to form an Au back electrode with a thickness of 100 nm, thereby obtaining the X-ray detector.
  • the current-voltage characteristics of the X-ray detector were tested using a Keithley SourceMeter 2700 and an X-ray source (Rigaku Smartlab 3kW X-ray diffractometer with Cu K ⁇ radiation).
  • the resulting IV curve is shown in FIG6 , where the horizontal axis represents the electric field (V/mm) and the vertical axis represents the current density (A/mm 2 ).
  • the dark current value is 10 -11 -10 -9 A ⁇ mm -2 , and the corresponding light current under bias is increased to 10 -9 -10 -7 A ⁇ mm -2 , which is more than 100 times higher.
  • the response current of the X-ray detector under different electric field strengths was tested by using a Keithley source meter 2700 and an X-ray source (Rigaku Smartlab 3kW X-ray diffractometer with Cu K ⁇ radiation) to change with the X-ray dose, so as to analyze and obtain the sensitivity of the detector.
  • the sensitivity test diagram of the X-ray detector under different electric field strengths is shown in FIG7 , where the horizontal axis is the X-ray dose rate (dose rate, unit: mG air /s), the vertical axis is the response current density (current density, unit: ⁇ A/cm 2 ), and the slope of the curve is the sensitivity of the X-ray detector.
  • the sensitivity of the X-ray detector under 20 V/mm is 1547 ⁇ C ⁇ Gy air -1 ⁇ cm -2
  • the sensitivity under 40 V/mm is 4334 ⁇ C ⁇ Gy air -1 ⁇ cm -2
  • the sensitivity under 60 V/mm is 7266 ⁇ C ⁇ Gy air -1 ⁇ cm -2
  • the sensitivity under 80 V/mm is 9341 ⁇ C ⁇ Gy air -1 ⁇ cm -2 .
  • the minimum detectable X-ray dose of the X-ray detector is 588 n Gy air ⁇ s -1 , and the signal-to-noise ratio (SNR) of the device is equal to 3.
  • An all-inorganic perovskite photosensitive layer and a preparation method thereof which differs from Example 1 only in that Example 3 is a CsPbCl 2 Br photosensitive layer, and the raw materials of step (1) are CsBr and PbCl 2 in a molar ratio of 1:1;
  • Example 4 is a CsPbClBr 2 photosensitive layer, and the raw materials of step (1) are CsCl and PbBr 2 in a molar ratio of 1:1; other materials, proportions and preparation methods are the same as those in Example 1, and an all-inorganic perovskite photosensitive layer is obtained.
  • An X-ray detector which is the same as Example 2 only in that the perovskite photosensitive layer is the aforementioned all-inorganic perovskite photosensitive layer; the other hierarchical structures, materials and preparation methods are the same as those of Example 2.
  • Example 2 The same test method as in Example 2 was used to perform performance tests on the detection sensitivity (80 V/mm) and the minimum detectable dose of the X-ray detector. The test results are shown in Table 1:
  • the preparation method provided by the present invention can be used to prepare different all-inorganic perovskite photosensitive layers, thereby obtaining different X-ray detectors; among them, the X-ray detector comprising the CsPbBr3 photosensitive layer in Example 1 has better sensitivity.
  • An X-ray detector which is the same as Example 2 only in that the perovskite photosensitive layer is the aforementioned all-inorganic perovskite photosensitive layer; the other hierarchical structures, materials and preparation methods are the same as those of Example 2.
  • Example 2 The same test method as in Example 2 was used to perform performance tests on the detection sensitivity (80 V/mm) and the minimum detectable dose of the X-ray detector. The test results are shown in Table 2:
  • An X-ray detector which is the same as Example 2 only in that the perovskite photosensitive layer is the aforementioned all-inorganic perovskite photosensitive layer; the other hierarchical structures, materials and preparation methods are the same as those of Example 2.
  • Example 2 The same test method as in Example 2 was used to perform performance tests on the detection sensitivity (80 V/mm) and the minimum detectable dose of the X-ray detector. The test results are shown in Table 3:
  • the present invention illustrates the all-inorganic perovskite photosensitive layer and its preparation method and application through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented.
  • Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

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Abstract

An all-inorganic perovskite photosensitive layer, and a preparation method therefor and the use thereof. The thickness of the all-inorganic perovskite photosensitive layer is greater than or equal to 90 μm. The preparation method comprises the following steps: (1) grinding an inorganic halide AX and an inorganic halide BY2, so as to obtain a perovskite material ABXY2; (2) mixing the perovskite material ABXY2 with an organic solvent, so as to obtain a perovskite precursor slurry; and (3) subjecting the perovskite precursor slurry to silk-screen printing to form a coating, and then annealing the coating, so as to obtain an all-inorganic perovskite photosensitive layer. The preparation method is a low-temperature liquid phase method including silk-screen printing, and has mild conditions, a simple process, and high operability; the obtained all-inorganic perovskite photosensitive layer has the characteristics of a large area, compactness and uniformity and high flatness; and the perovskite has a high crystal quality and good stability, and can fully absorb and convert high-energy X-rays, such that an X-ray detector comprising same has good stability and sensitivity.

Description

一种全无机钙钛矿光敏层及其制备方法和应用A fully inorganic perovskite photosensitive layer and its preparation method and application 技术领域Technical Field
本发明属于光电材料技术领域，具体涉及一种全无机钙钛矿光敏层及其制备方法和应用。The present invention belongs to the technical field of optoelectronic materials, and specifically relates to an all-inorganic perovskite photosensitive layer and a preparation method and application thereof.
背景技术Background technique
X射线探测器（X-ray detector）在成像、工业材料检测、核电站安全、国防科技、医学等领域中有着十分广泛的应用。近年来，卤化物钙钛矿材料在X射线探测研究领域备受关注，凭借较高的X射线吸收系数、较大的载流子扩散距离、较高的体相电阻率、卓越的材料可塑性、优异的液相工艺兼容性、灵活的器件界面可调性等优异特性，钙钛矿材料在实现X射线低辐射剂量成像、高分辨成像、快速动态成像、柔性成像等方面表现出无与伦比的杰出潜力，迅速成为下一代X射线探测与成像系统的首选材料之一。X-ray detectors are widely used in imaging, industrial material testing, nuclear power plant safety, national defense science and technology, medicine, etc. In recent years, halide perovskite materials have attracted much attention in the field of X-ray detection research. With their high X-ray absorption coefficient, large carrier diffusion distance, high bulk resistivity, excellent material plasticity, excellent liquid phase process compatibility, flexible device interface adjustability and other excellent properties, perovskite materials have shown unparalleled outstanding potential in achieving X-ray low radiation dose imaging, high-resolution imaging, fast dynamic imaging, flexible imaging, etc., and have quickly become one of the preferred materials for the next generation of X-ray detection and imaging systems.
制备高质量钙钛矿X射线光敏层是获得高性能探测器的关键，常见的钙钛矿光敏层有单晶、多晶压片和多晶厚膜三种形式。例如CN112071989A公开了一种基于钙钛矿单晶的X射线探测器及其制备方法，所述X射线探测器由钙钛矿单晶以及位于钙钛矿单晶两侧的Au和Ga电极组成，制备方法如下：通过改进的缓慢升温方法生长得到FAPbBr 3钙钛矿单晶，先在钙钛矿单晶生长液中先制备籽晶晶粒，之后挑选形状规则的籽晶转移至新配置的溶液中继续生长，直至晶体具有合适的大小，完成单晶制备。CN112142100A公开了一种钙钛矿多晶薄片及其制备方法和应用，首先利用溶液法、通过PbX 2粉末和AX的反应制备出钙钛矿粉末APbX 3，然后将钙钛矿粉末在高温高压下原位热压，制备成钙钛矿多晶薄片；A为Cs、CH 2NH 3或CH(NH 3) 2，X为卤素。总体而言，单晶缺陷少，探测效率较低，但是无法通过溶液法生长获得大面积；多晶压片可以获得大面积的钙钛矿层，但制备过程需要高温高压，会造成钙钛矿材料分解，引入晶体缺陷；此外，单晶和多晶压片都无法实现与基板和像素芯片直接集成，极大限制了其在X射线探测成像方面的应用。 The preparation of high-quality perovskite X-ray photosensitive layers is the key to obtaining high-performance detectors. Common perovskite photosensitive layers are in the form of single crystals, polycrystalline pressed sheets, and polycrystalline thick films. For example, CN112071989A discloses an X-ray detector based on a perovskite single crystal and a preparation method thereof, wherein the X-ray detector is composed of a perovskite single crystal and Au and Ga electrodes located on both sides of the perovskite single crystal. The preparation method is as follows: a FAPbBr 3 perovskite single crystal is grown by an improved slow heating method, seed crystal grains are first prepared in a perovskite single crystal growth solution, and then seed crystals with regular shapes are selected and transferred to a newly configured solution for continued growth until the crystal has a suitable size, thereby completing the single crystal preparation. CN112142100A discloses a perovskite polycrystalline thin slice and its preparation method and application. First, a perovskite powder APbX 3 is prepared by a solution method through the reaction of PbX 2 powder and AX, and then the perovskite powder is hot-pressed in situ under high temperature and high pressure to prepare a perovskite polycrystalline thin slice; A is Cs, CH 2 NH 3 or CH(NH 3 ) 2 , and X is a halogen. In general, single crystals have fewer defects and lower detection efficiency, but cannot be grown in a large area by a solution method; polycrystalline pressed sheets can obtain a large area of perovskite layer, but the preparation process requires high temperature and high pressure, which will cause the perovskite material to decompose and introduce crystal defects; in addition, both single crystals and polycrystalline pressed sheets cannot be directly integrated with substrates and pixel chips, which greatly limits their application in X-ray detection imaging.
液相法是原位生长制备钙钛矿薄膜（几百纳米）的常用方法，常用于钙钛矿太阳电池和发光二极管，具体包括：首先将钙钛矿的前驱体材料全部溶解于 N,N-二甲基甲酰胺（DMF）、二甲基亚砜（DMSO）、γ-丁内酯（GBL）等有机溶剂中，然后通过旋涂、刮涂、喷涂、喷墨打印、狭缝涂布等方法制备钙钛矿薄膜。例如CN109920918A公开了一种钙钛矿光电探测器，其结构从下到上依次为衬底、导电阳极、空穴传输层、钙钛矿光活性层，复合电子传输层、空穴阻挡层与金属阴极；其中，所述复合电子传输层由PCBM和明胶构成，所述钙钛矿光活性层的材料为MAPbI 3，厚度为300-700 nm，其采用旋涂钙钛矿溶液并退火的方法制备得。液相法制备钙钛矿膜层的条件温和，并有望与多像素芯片（TFT、CMOS）集成；但是，高能X/γ射线能量强，需要钙钛矿厚膜（几百微米）才能将其充分的吸收转化，然而，受限于钙钛矿前驱体材料在溶液（DMF、GBL、DMSO）中的溶解度，目前用液相法在基板上制备大面积致密钙钛矿厚膜仍然具有很大的挑战性，尚缺少操作性强、工艺简单的制备方法。而且，目前常用的钙钛矿厚膜材料为有机-无机杂化钙钛矿材料（例如MAPbI 3、FAPbI 3、FAPbBr 3等），其环境湿度稳定性不佳，热稳定性差，严重影响了探测器件的稳定性。 The liquid phase method is a common method for in-situ growth and preparation of perovskite thin films (several hundred nanometers), which is commonly used in perovskite solar cells and light-emitting diodes. Specifically, the following steps are: first, all the precursor materials of the perovskite are dissolved in organic solvents such as N,N -dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and γ-butyrolactone (GBL), and then the perovskite thin film is prepared by spin coating, scraping, spraying, inkjet printing, slit coating, etc. For example, CN109920918A discloses a perovskite photodetector, whose structure from bottom to top is substrate, conductive anode, hole transport layer, perovskite photoactive layer, composite electron transport layer, hole blocking layer and metal cathode; wherein the composite electron transport layer is composed of PCBM and gelatin, and the material of the perovskite photoactive layer is MAPbI 3 with a thickness of 300-700 nm, which is prepared by spin coating the perovskite solution and annealing. The conditions for preparing perovskite films by liquid phase method are mild, and it is expected to be integrated with multi-pixel chips (TFT, CMOS); however, high-energy X/γ-rays have strong energy, and thick perovskite films (several hundred microns) are required to fully absorb and convert them. However, due to the solubility of perovskite precursor materials in solutions (DMF, GBL, DMSO), it is still very challenging to prepare large-area dense perovskite thick films on substrates by liquid phase method, and there is still a lack of preparation methods with strong operability and simple process. Moreover, the commonly used perovskite thick film materials are organic-inorganic hybrid perovskite materials (such as MAPbI 3 , FAPbI 3 , FAPbBr 3 , etc.), which have poor environmental humidity stability and poor thermal stability, which seriously affects the stability of detection devices.
技术问题technical problem
因此，开发一种工艺简单、可操作性强、钙钛矿材料的稳定性高的钙钛矿厚膜的制备方法，是本领域亟待解决的问题。Therefore, developing a method for preparing a thick perovskite film with simple process, strong operability and high stability of the perovskite material is an urgent problem to be solved in this field.
技术解决方案Technical Solutions
针对现有技术的不足，本发明的目的在于提供一种全无机钙钛矿光敏层及其制备方法和应用，所述全无机钙钛矿光敏层通过包含丝网印刷的低温液相法制备得到，工艺简单、可操作性强，实现了钙钛矿厚膜的大面积制备，得到的全无机钙钛矿光敏层致密、均匀、平整度高，环境稳定性好，使包含其的X射线探测器具有优异的稳定性和灵敏度。In view of the deficiencies in the prior art, the object of the present invention is to provide an all-inorganic perovskite photosensitive layer and a preparation method and application thereof. The all-inorganic perovskite photosensitive layer is prepared by a low-temperature liquid phase method including screen printing, which has a simple process and strong operability, and realizes large-area preparation of perovskite thick films. The obtained all-inorganic perovskite photosensitive layer is dense, uniform, and has high flatness and good environmental stability, so that the X-ray detector containing it has excellent stability and sensitivity.
为达到此发明目的，本发明采用以下技术方案：In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:
第一方面，本发明提供一种全无机钙钛矿光敏层的制备方法，所述全无机钙钛矿光敏层的厚度≥90 μm；所述制备方法包括如下步骤：In a first aspect, the present invention provides a method for preparing an all-inorganic perovskite photosensitive layer, wherein the thickness of the all-inorganic perovskite photosensitive layer is ≥ 90 μm; the preparation method comprises the following steps:
（1）将无机卤化物AX与无机卤化物BY 2进行研磨，得到钙钛矿材料ABXY 2；所述A为Cs、Bi或Rb，所述B为Pb、Sn或Ge，所述X、Y各自独立地为卤素； (1) grinding an inorganic halide AX and an inorganic halide BY 2 to obtain a perovskite material ABXY 2 ; A is Cs, Bi or Rb, B is Pb, Sn or Ge, and X and Y are each independently a halogen;
（2）步骤（1）得到的钙钛矿材料ABXY 2与有机溶剂混合，得到钙钛矿前驱体浆料； (2) The perovskite material ABXY2 obtained in step (1) is mixed with an organic solvent to obtain a perovskite precursor slurry;
（3）步骤（2）得到的钙钛矿前驱体浆料通过丝网印刷形成涂层，所述涂层经过退火，得到所述全无机钙钛矿光敏层。(3) The perovskite precursor slurry obtained in step (2) is formed into a coating by screen printing, and the coating is annealed to obtain the all-inorganic perovskite photosensitive layer.
本发明提供的制备方法中，首先将无机卤化物AX与BY 2进行研磨，得到全无机的钙钛矿材料ABXY 2，然后将其与有机溶剂混合均匀，得到全无机的钙钛矿前驱体浆料；所述钙钛矿前驱体浆料通过丝网印刷的方式形成涂层，经过退火处理和原位生长后，得到大面积、平整、致密均匀的所述全无机钙钛矿光敏层。与现有技术中多晶压片的方法相比，本发明所述制备方法为低温液相法工艺，条件温和，工艺简单、可操作性强，能够在导电基底或像素芯片上直接原位生长得到厚度≥90 μm的大面积的钙钛矿厚膜，实现良好的键合集成；而且所述全无机钙钛矿光敏层中，钙钛矿的结晶度高，晶体缺陷少，具有优异的环境湿度稳定性和热稳定性，能够充分吸收转化高能X/γ射线，使包含其的X射线探测器的暗电流降低，提升器件的老化稳定性和载流子传输性能，从而有效改善X射线探测器的灵敏度和稳定性。 In the preparation method provided by the present invention, the inorganic halide AX and BY 2 are first ground to obtain an all-inorganic perovskite material ABXY 2 , which is then uniformly mixed with an organic solvent to obtain an all-inorganic perovskite precursor slurry; the perovskite precursor slurry is formed into a coating by screen printing, and after annealing and in-situ growth, a large-area, flat, dense and uniform all-inorganic perovskite photosensitive layer is obtained. Compared with the polycrystalline pressing method in the prior art, the preparation method of the present invention is a low-temperature liquid phase process with mild conditions, simple process and strong operability. It can directly grow in situ on a conductive substrate or a pixel chip to obtain a large-area perovskite thick film with a thickness of ≥90 μm, thereby achieving good bonding integration. Moreover, in the all-inorganic perovskite photosensitive layer, the perovskite has high crystallinity, few crystal defects, excellent environmental humidity stability and thermal stability, and can fully absorb and convert high-energy X/γ rays, thereby reducing the dark current of the X-ray detector containing it, improving the aging stability and carrier transport performance of the device, thereby effectively improving the sensitivity and stability of the X-ray detector.
优选地，所述A为Cs，所述无机卤化物AX为CsX。Preferably, the A is Cs, and the inorganic halide AX is CsX.
优选地，所述B为Pb，所述无机卤化物BY 2为PbY 2。 Preferably, the B is Pb, and the inorganic halide BY 2 is PbY 2 .
优选地，所述X和Y各自独立地为Cl、Br或I，进一步优选为Cl或Br。Preferably, X and Y are each independently Cl, Br or I, more preferably Cl or Br.
优选地，所述无机卤化物AX为CsCl和/或CsBr。Preferably, the inorganic halide AX is CsCl and/or CsBr.
优选地，所述无机卤化物BY 2为PbCl 2和/或PbBr 2。 Preferably, the inorganic halide BY 2 is PbCl 2 and/or PbBr 2 .
优选地，步骤（1）所述钙钛矿材料ABXY 2包括CsPbCl 3、CsPbBr 3、CsPbClBr 2或CsPbCl 2Br。 Preferably, the perovskite material ABXY 2 in step (1) includes CsPbCl 3 , CsPbBr 3 , CsPbClBr 2 or CsPbCl 2 Br.
优选地，所述无机卤化物AX与无机卤化物BY 2的摩尔比为1:(0.5-2),例如可以为1:0.6、1:0.8、1:1、1:1.1、1:1.3、1:1.5、1:1.7或1:1.9等。 Preferably, the molar ratio of the inorganic halide AX to the inorganic halide BY 2 is 1:(0.5-2), for example, it can be 1:0.6, 1:0.8, 1:1, 1:1.1, 1:1.3, 1:1.5, 1:1.7 or 1:1.9, etc.
优选地，步骤（1）所述研磨为机械研磨。Preferably, the grinding in step (1) is mechanical grinding.
优选地，步骤（1）所述研磨为干法研磨，研磨的过程中无需加入溶剂。Preferably, the grinding in step (1) is dry grinding, and no solvent is required to be added during the grinding process.
优选地，步骤（1）所述研磨的方法为球磨。Preferably, the grinding method in step (1) is ball milling.
优选地，所述球磨的球料比为1:(1-5)，例如可以为1:1.2、1:1.5、1:1.8、1:2、1:2.2、1:2.5、1:2.8、1:3、1:3.2、1:3.5、1:3.8、1:4、1:4.2、1:4.5或1:4.8等。Preferably, the ball-to-material ratio of the ball mill is 1:(1-5), for example, it can be 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, 1:4.2, 1:4.5 or 1:4.8, etc.
本文中，所述球料比为球磨球与原料（无机卤化物AX与无机卤化物BY 2）的质量比。 Herein, the ball-to-material ratio is the mass ratio of the ball milling balls to the raw materials (inorganic halide AX and inorganic halide BY 2 ).
优选地，所述球磨的转速为200-1000 rpm，例如可以为300 rpm、400 rpm、500 rpm、600 rpm、700 rpm、800 rpm或900 rpm等。Preferably, the rotation speed of the ball mill is 200-1000 rpm, for example, it can be 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or 900 rpm.
优选地，所述球磨的时间为0.5-6 h，例如可以为1 h、1.5 h、2 h、2.5 h、3 h、3.5 h、4 h、4.5 h、5 h或5.5 h等。Preferably, the ball milling time is 0.5-6 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h or 5.5 h.
优选地，所述球磨在行星球磨机中进行。Preferably, the ball milling is carried out in a planetary ball mill.
优选地，步骤（2）所述有机溶剂包括二甲基亚砜（DMSO）、 N,N-二甲基甲酰胺（DMF）、 N,N-二甲基乙酰胺（DMAC）或γ-丁内酯（GBL）中的任意一种或至少两种的组合，进一步优选二甲基亚砜和 N,N-二甲基甲酰胺的组合。 Preferably, the organic solvent in step (2) comprises any one or a combination of at least two of dimethyl sulfoxide (DMSO), N,N -dimethylformamide (DMF), N,N -dimethylacetamide (DMAC) or γ-butyrolactone (GBL), and more preferably a combination of dimethyl sulfoxide and N,N -dimethylformamide.
优选地，所述二甲基亚砜与 N,N-二甲基甲酰胺的体积比为(0.5-5):1，例如可以为0.6:1、0.8:1、1:1、1.5:1、2:1、2.5:1、3:1、3.5:1、4:1或4.5:1等。 Preferably, the volume ratio of dimethyl sulfoxide to N,N -dimethylformamide is (0.5-5):1, for example, it can be 0.6:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1 or 4.5:1, etc.
作为本发明的优选技术方案，步骤（2）所述有机溶剂为DMSO和DMF的组合；特定的有机溶剂有助于钙钛矿材料ABXY 2微晶的再生长，从而获得高质量的全无机钙钛矿；而且，所述有机溶剂中DMSO的含量提高，能够进一步提升钙钛矿材料ABXY 2微晶的再生长效果；当DMSO与DMF的的体积比为1:1时，得到的钙钛矿材料ABXY 2微晶（例如CsPbBr 3微晶）具有明显的方块状。 As a preferred technical solution of the present invention, the organic solvent in step (2) is a combination of DMSO and DMF; the specific organic solvent is conducive to the regrowth of the perovskite material ABXY2 microcrystals, thereby obtaining high-quality all-inorganic perovskite; and the increase in the DMSO content in the organic solvent can further enhance the regrowth effect of the perovskite material ABXY2 microcrystals; when the volume ratio of DMSO to DMF is 1:1, the obtained perovskite material ABXY2 microcrystals (such as CsPbBr3 microcrystals) have obvious block shape.
优选地，步骤（2）所述钙钛矿材料ABXY 2与有机溶剂的质量比为(3-5):1，例如可以为3.1:1、3.3:1、3.5:1、3.7:1、3.9:1、4:1、4.1:1、4.3:1、4.5:1、4.7:1或4.9:1等。 Preferably, in step (2), the mass ratio of the perovskite material ABXY2 to the organic solvent is (3-5):1, for example, it can be 3.1:1, 3.3:1, 3.5:1, 3.7:1, 3.9:1, 4:1, 4.1:1, 4.3:1, 4.5:1, 4.7:1 or 4.9:1, etc.
优选地，步骤（2）所述混合的物料还包括粘度调节剂。Preferably, the mixed material in step (2) further includes a viscosity regulator.
优选地，所述粘度调节剂包括松油醇和/或纤维素。Preferably, the viscosity modifier comprises terpineol and/or cellulose.
作为本发明的优选技术方案，步骤（2）所述混合的物料包括松油醇和/或纤维素，所述松油醇作为反溶剂，所述纤维素作为增稠剂，有助于调整所述钙钛矿前驱体浆料的粘稠度。As a preferred technical solution of the present invention, the mixed material in step (2) includes pinene alcohol and/or cellulose, the pinene alcohol serves as an anti-solvent, and the cellulose serves as a thickener, which helps to adjust the viscosity of the perovskite precursor slurry.
优选地，所述纤维素包括乙基纤维素。Preferably, the cellulose comprises ethyl cellulose.
优选地，所述松油醇与有机溶剂的体积比为1:(4-8)，例如可以为1:4.2、1:4.5、1:4.8、1:5、1:5.2、1:5.5、1:5.8、1:6、1:6.2、1:6.5、1:6.8、1:7、1:7.2、1:7.5或1:7.8等。Preferably, the volume ratio of terpineol to organic solvent is 1:(4-8), for example, it can be 1:4.2, 1:4.5, 1:4.8, 1:5, 1:5.2, 1:5.5, 1:5.8, 1:6, 1:6.2, 1:6.5, 1:6.8, 1:7, 1:7.2, 1:7.5 or 1:7.8, etc.
优选地，所述纤维素与钙钛矿材料ABXY 2的质量比为1:(10-20)，例如可以为1:11、1:12、1:13、1:14、1:15、1:16、1:17、1:18或1:19等。 Preferably, the mass ratio of cellulose to perovskite material ABXY2 is 1:(10-20), for example, it can be 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18 or 1:19, etc.
优选地，步骤（2）所述混合后还包括研磨的步骤。Preferably, step (2) further includes a grinding step after the mixing.
优选地，所述研磨的时间为0.5-3 h，例如可以为0.8 h、1 h、1.2 h、1.5 h、1.8 h、2 h、2.2 h、2.5 h或2.8 h等；所述研磨的过程有助于形成分散更加均匀的钙钛矿前驱体浆料。Preferably, the grinding time is 0.5-3 h, for example, 0.8 h, 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h, 2.2 h, 2.5 h or 2.8 h, etc.; the grinding process helps to form a more evenly dispersed perovskite precursor slurry.
优选地，步骤（2）所述钙钛矿前驱体浆料的固含量为70-90%，例如可以为71%、73%、75%、77%、79%、80%、81%、83%、85%、87%或89%等。Preferably, the solid content of the perovskite precursor slurry in step (2) is 70-90%, for example, it can be 71%, 73%, 75%, 77%, 79%, 80%, 81%, 83%, 85%, 87% or 89%.
优选地，步骤（3）通过丝网印刷在导电基底上形成涂层。Preferably, step (3) forms the coating on the conductive substrate by screen printing.
优选地，所述导电基底包括ITO导电基底、FTO导电基体、TFT像素芯片或CMOS像素芯片。Preferably, the conductive substrate includes an ITO conductive substrate, a FTO conductive substrate, a TFT pixel chip or a CMOS pixel chip.
优选地，步骤（3）所述丝网印刷的次数为1-5次，例如可以为2次、3次或4次等。Preferably, the number of screen printing in step (3) is 1-5 times, for example, 2 times, 3 times or 4 times.
优选地，步骤（3）所述丝网印刷的丝网孔径为200-500目，例如可以为220目、250目、280目、300目、320目、350目、380目、400目、420目、450目或480目等。Preferably, the aperture of the screen printing in step (3) is 200-500 mesh, for example, 220 mesh, 250 mesh, 280 mesh, 300 mesh, 320 mesh, 350 mesh, 380 mesh, 400 mesh, 420 mesh, 450 mesh or 480 mesh.
作为本发明的优选技术方案，所述制备方法中，通过所述钙钛矿前驱体浆料的粘稠度、丝网印刷的次数、丝网孔径的设计及复配，从而得到不同厚度的所述全无机钙钛矿光敏层，用于吸收不同能量的X射线。As a preferred technical solution of the present invention, in the preparation method, the viscosity of the perovskite precursor slurry, the number of screen printing, and the design and compounding of the screen aperture are adjusted to obtain the all-inorganic perovskite photosensitive layer of different thicknesses for absorbing X-rays of different energies.
优选地，步骤（3）所述退火的温度为80-150℃，例如可以为85℃、90℃、95℃、100℃、105℃、110℃、115℃、120℃、125℃、130℃、135℃、140℃或145℃等。Preferably, the annealing temperature in step (3) is 80-150°C, for example, it can be 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C or 145°C, etc.
优选地，步骤（3）所述退火的时间为0.5-2 h，例如可以为0.6 h、0.8 h、1 h、1.1 h、1.3 h、1.5 h、1.7 h或1.9 h等。Preferably, the annealing time in step (3) is 0.5-2 h, for example, it can be 0.6 h, 0.8 h, 1 h, 1.1 h, 1.3 h, 1.5 h, 1.7 h or 1.9 h.
优选地，步骤（3）所述退火包括依次进行的第一阶段退火和第二阶段退火，所述第一阶段退火的温度＜第二阶段退火的温度。Preferably, the annealing in step (3) includes a first stage annealing and a second stage annealing performed sequentially, and the temperature of the first stage annealing is less than the temperature of the second stage annealing.
优选地，所述第一阶段退火的温度为80-120℃，例如可以为82℃、85℃、88℃、90℃、92℃、95℃、98℃、100℃、102℃、105℃、108℃、110℃、112℃、115℃或118℃等。Preferably, the temperature of the first stage annealing is 80-120°C, for example, it can be 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, 100°C, 102°C, 105°C, 108°C, 110°C, 112°C, 115°C or 118°C, etc.
优选地，所述第一阶段退火的时间为10-40 min，例如可以为15 min、20 min、25 min、30 min或35 min等。Preferably, the first stage annealing time is 10-40 min, for example, 15 min, 20 min, 25 min, 30 min or 35 min.
优选地，所述第二阶段退火的温度为125-150℃，例如可以为128℃、130℃、132℃、135℃、138℃、140℃、142℃、145℃或148℃等。Preferably, the temperature of the second stage annealing is 125-150°C, for example, it can be 128°C, 130°C, 132°C, 135°C, 138°C, 140°C, 142°C, 145°C or 148°C.
优选地，所述第二阶段退火的时间为20-80 min，例如可以为25 min、30 min、35 min、40 min、45 min、50 min、55 min、60 min、65 min、70 min或75 min等。Preferably, the second stage annealing time is 20-80 min, for example, it can be 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min or 75 min, etc.
作为本发明的优选技术方案，步骤（3）中，通过退火的工艺参数的设计和精确控制，包括温度、升温速率、时间、梯度加热等条件的控制，使溶剂充分挥发，并能够有效调控钙钛矿厚膜的晶体生长，提升钙钛矿的结晶度、修饰缺陷，提高材料光电特性，获得具有高结晶度、低缺陷的钙钛矿晶体，得到高品质的所述全无机钙钛矿光敏层。As a preferred technical solution of the present invention, in step (3), by designing and precisely controlling the process parameters of annealing, including the control of temperature, heating rate, time, gradient heating and other conditions, the solvent is fully volatilized, and the crystal growth of the perovskite thick film can be effectively regulated, the crystallinity of the perovskite is improved, defects are modified, and the photoelectric properties of the material are improved, so that perovskite crystals with high crystallinity and low defects are obtained, thereby obtaining the high-quality all-inorganic perovskite photosensitive layer.
优选地，所述全无机钙钛矿光敏层的厚度≥90 μm，所述制备方法具体包括如下步骤：Preferably, the thickness of the all-inorganic perovskite photosensitive layer is ≥90 μm, and the preparation method specifically comprises the following steps:
（1）将无机卤化物AX与无机卤化物BY 2以摩尔比1:(0.5-2)混合后进行球磨，得到钙钛矿材料ABXY 2；所述A为Cs、Bi或Rb，所述B为Pb、Sn或Ge，所述X和Y各自独立地为卤素；所述球磨的球料比为1:(1-5)，转速为200-1000 rpm，时间为0.5-6 h； (1) Mixing an inorganic halide AX and an inorganic halide BY2 in a molar ratio of 1:(0.5-2) and ball milling to obtain a perovskite material ABXY2 ; wherein A is Cs, Bi or Rb, B is Pb, Sn or Ge, and X and Y are independently halogens; the ball-to-material ratio of the ball milling is 1:(1-5), the rotation speed is 200-1000 rpm, and the time is 0.5-6 h;
（2）步骤（1）得到的钙钛矿材料ABXY 2与有机溶剂混合并研磨，得到钙钛矿前驱体浆料；所述有机溶剂包括体积比为(0.5-5):1的二甲基亚砜和 N,N-二甲基甲酰胺；所述钙钛矿材料ABXY 2与有机溶剂的质量比为(3-5):1； (2) The perovskite material ABXY2 obtained in step (1) is mixed with an organic solvent and ground to obtain a perovskite precursor slurry; the organic solvent comprises dimethyl sulfoxide and N,N -dimethylformamide in a volume ratio of (0.5-5):1; the mass ratio of the perovskite material ABXY2 to the organic solvent is (3-5):1;
（3）步骤（2）得到的钙钛矿前驱体浆料通过丝网印刷形成涂层，所述涂层依次进行第一阶段退火和第二阶段退火，得到所述全无机钙钛矿光敏层；所述第一阶段退火的温度为80-120℃，时间为10-40 min；所述第二阶段退火的温度为125-150℃，时间为20-80 min。(3) The perovskite precursor slurry obtained in step (2) is formed into a coating by screen printing, and the coating is subjected to a first stage annealing and a second stage annealing in sequence to obtain the all-inorganic perovskite photosensitive layer; the temperature of the first stage annealing is 80-120°C and the time is 10-40 min; the temperature of the second stage annealing is 125-150°C and the time is 20-80 min.
第二方面，本发明提供一种全无机钙钛矿光敏层，所述全无机钙钛矿光敏层通过如第一方面所述的制备方法制备得到。In a second aspect, the present invention provides an all-inorganic perovskite photosensitive layer, which is prepared by the preparation method described in the first aspect.
优选地，所述全无机钙钛矿光敏层的厚度为90-500 μm，例如可以为100 μm、120 μm、150 μm、180 μm、200 μm、220 μm、250 μm、280 μm、300 μm、320 μm、350 μm、380 μm、400 μm、420 μm、450 μm或480 μm等。Preferably, the thickness of the all-inorganic perovskite photosensitive layer is 90-500 μm, for example, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm, 280 μm, 300 μm, 320 μm, 350 μm, 380 μm, 400 μm, 420 μm, 450 μm or 480 μm, etc.
第三方面，本发明提供一种如第二方面所述的全无机钙钛矿光敏层在钙钛矿电池或钙钛矿探测器件中的应用。In a third aspect, the present invention provides a use of the all-inorganic perovskite photosensitive layer as described in the second aspect in a perovskite cell or a perovskite detection device.
优选地，所述钙钛矿探测器件包括X/γ射线探测器。Preferably, the perovskite detection device comprises an X/γ-ray detector.
优选地，所述钙钛矿探测器件为X射线探测器。Preferably, the perovskite detection device is an X-ray detector.
第四方面，本发明提供一种X射线探测器，所述X射线探测器包括导电基底、钙钛矿光敏层、传输层和背电极；所述钙钛矿光敏层为第二方面所述的全无机钙钛矿光敏层。In a fourth aspect, the present invention provides an X-ray detector, comprising a conductive substrate, a perovskite photosensitive layer, a transmission layer and a back electrode; the perovskite photosensitive layer is the all-inorganic perovskite photosensitive layer described in the second aspect.
本发明中，所述X射线探测器为包括电极材料、所述全无机钙钛矿光敏层和传输层的P-I-N型或N-I-P型光敏二极管型器件结构。In the present invention, the X-ray detector is a P-I-N type or N-I-P type photodiode device structure including an electrode material, the all-inorganic perovskite photosensitive layer and a transmission layer.
优选地，所述导电基底包括ITO导电基底、FTO导电基体、TFT像素芯片或CMOS像素芯片。Preferably, the conductive substrate includes an ITO conductive substrate, a FTO conductive substrate, a TFT pixel chip or a CMOS pixel chip.
优选地，所述导电基底包括ITO导电基底，其包括ITO导电层和基底层，所述ITO导电层位于靠近所述钙钛矿光敏层的一侧。Preferably, the conductive substrate comprises an ITO conductive substrate, which comprises an ITO conductive layer and a substrate layer, and the ITO conductive layer is located on a side close to the perovskite photosensitive layer.
优选地，所述传输层的材料包括为本领域常用的传输层材料，示例性地包括但不限于：富勒烯（C60）、富勒烯衍生物（例如PCBM）、BCP、聚噻吩类（例如PEDOT:PSS、P3HT）、聚苯胺类（例如poly-TPD、PTAA）、镍氧化物（NiO X）、芳胺类化合物（例如TAPC）、钛氧化物（TiO X）、钼氧化物（MoO X，例如MoO 3）、V 2O 5或WO 3等材料中的一种或至少两种的组合。 Preferably, the material of the transport layer includes a commonly used transport layer material in the art, illustratively including but not limited to: fullerene (C60), fullerene derivatives (such as PCBM), BCP, polythiophenes (such as PEDOT:PSS, P3HT), polyanilines (such as poly-TPD, PTAA), nickel oxide (NiO X ), aromatic amine compounds (such as TAPC), titanium oxide (TiO X ), molybdenum oxide (MoO X , such as MoO 3 ), V 2 O 5 or WO 3 , etc. One or a combination of at least two of the materials.
优选地，所述传输层为单层结构或多层结构。Preferably, the transmission layer is a single-layer structure or a multi-layer structure.
优选地，所述传输层为电子传输层。Preferably, the transport layer is an electron transport layer.
优选地，所述X射线探测器包括依次设置的导电基底、所述全无机钙钛矿光敏层、电子传输层和背电极。Preferably, the X-ray detector comprises a conductive substrate, the all-inorganic perovskite photosensitive layer, an electron transport layer and a back electrode which are arranged in sequence.
优选地，所述电子传输层包括富勒烯衍生物电子传输层，进一步优选PCBM电子传输层。Preferably, the electron transport layer comprises a fullerene derivative electron transport layer, and more preferably a PCBM electron transport layer.
优选地，所述电子传输层的厚度为1-100 nm，例如可以为5 nm、10 nm、20 nm、30 nm、40 nm、50 nm、60 nm、70 nm、80 nm或90 nm等。Preferably, the thickness of the electron transport layer is 1-100 nm, for example, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm or 90 nm.
优选地，所述背电极包括金属电极或碳电极。Preferably, the back electrode comprises a metal electrode or a carbon electrode.
优选地，所述背电极为金属电极，材料包括Cu、Ag、Au、Al、Cr中的任意一种或至少两种的组合，进一步优选包括Au电极。Preferably, the back electrode is a metal electrode, and the material includes any one of Cu, Ag, Au, Al, and Cr, or a combination of at least two thereof, and more preferably includes an Au electrode.
优选地，所述背电极的厚度为50-200 nm，例如可以为60 nm、80 nm、100 nm、110 nm、130 nm、150 nm、170 nm或190 nm等。Preferably, the thickness of the back electrode is 50-200 nm, for example, 60 nm, 80 nm, 100 nm, 110 nm, 130 nm, 150 nm, 170 nm or 190 nm.
作为本发明的优选技术方案，本发明制备得到的全无机钙钛矿光敏层具有大面积、致密、均匀和平整的特点，钙钛矿的结晶度高、缺陷少，具有优异的晶体质量，从而有效降低了包含所述全无机钙钛矿光敏层的X射线探测器的暗电流，提升器件的老化稳定性和载流子传输性能。As a preferred technical solution of the present invention, the all-inorganic perovskite photosensitive layer prepared by the present invention has the characteristics of large area, density, uniformity and flatness. The perovskite has high crystallinity, few defects and excellent crystal quality, thereby effectively reducing the dark current of the X-ray detector containing the all-inorganic perovskite photosensitive layer and improving the aging stability and carrier transport performance of the device.
优选地，所述全无机钙钛矿（CsPbBr 3）光敏层的厚度为300 μm，X射线探测器的暗电流（dark current）为10 -11-10 -9 A·mm -2，对应偏压下的光电流（light current）提高至10 -9-10 -7 A·mm -2，有了100倍以上的提升；同时，所述X射线探测器在20 V/mm下的灵敏度为1547 μC·Gy air -1·cm -2，40 V/mm下的灵敏度为4334 μC·Gy air -1·cm -2，60 V/mm下的灵敏度为7266 μC·Gy air -1·cm -2，80 V/mm下的灵敏度为9341 μC·Gy air -1·cm -2；所述X射线探测器的最低可探测X射线的剂量为588 n Gy air·s -1，此时器件的信噪比（SNR）为3，具有优异的灵敏度。 Preferably, the thickness of the all-inorganic perovskite (CsPbBr 3 ) photosensitive layer is 300 μm, the dark current of the X-ray detector is 10 -11 -10 -9 A·mm -2 , and the corresponding photocurrent under bias is increased to 10 -9 -10 -7 A·mm -2 , which is more than 100 times higher; at the same time, the sensitivity of the X-ray detector at 20 V/mm is 1547 μC·Gy air -1 ·cm -2 , the sensitivity at 40 V/mm is 4334 μC·Gy air -1 ·cm -2 , the sensitivity at 60 V/mm is 7266 μC·Gy air -1 ·cm -2 , and the sensitivity at 80 V/mm is 9341 μC·Gy air -1 ·cm -2 ; the minimum detectable X-ray dose of the X-ray detector is 588 n Gy air ·s -1 At this time, the signal-to-noise ratio (SNR) of the device is 3, which has excellent sensitivity.
第五方面，本发明提供一种如第四方面所述的X射线探测器的制备方法，所述制备方法包括：In a fifth aspect, the present invention provides a method for preparing the X-ray detector according to the fourth aspect, the preparation method comprising:
采用如第一方面所述的制备方法在导电基底的导电层（例如ITO导电层）上制备全无机钙钛矿光敏层；The all-inorganic perovskite photosensitive layer is prepared on the conductive layer (such as ITO conductive layer) of the conductive substrate by using the preparation method described in the first aspect;
在所述全无机钙钛矿光敏层上依次涂布电子传输层材料、干燥、真空蒸镀背电极材料，得到所述X射线探测器；Sequentially coating the electron transport layer material on the all-inorganic perovskite photosensitive layer, drying, and vacuum evaporating the back electrode material to obtain the X-ray detector;
优选地，所述涂布电子传输层材料的方法包括旋涂，即旋涂包含所述电子传输层材料的溶液。Preferably, the method of coating the electron transport layer material comprises spin coating, ie, spin coating a solution containing the electron transport layer material.
优选地，所述溶液中电子传输层材料的浓度为10-30 mg/mL，例如可以为12 mg/mL、15 mg/mL、18 mg/mL、20 mg/mL、22 mg/mL、25 mg/mL或28 mg/mL等。Preferably, the concentration of the electron transport layer material in the solution is 10-30 mg/mL, for example, 12 mg/mL, 15 mg/mL, 18 mg/mL, 20 mg/mL, 22 mg/mL, 25 mg/mL or 28 mg/mL.
优选地，所述溶液的溶剂为氯苯、氯仿、邻二氯苯或邻二甲苯中的任意一种或至少两种的组合。Preferably, the solvent of the solution is any one of chlorobenzene, chloroform, o-dichlorobenzene or o-xylene, or a combination of at least two of them.
优选地，所述旋涂的转速为2000-6000 rpm，例如可以为2500 rpm、3000 rpm、3500 rpm、4000 rpm、4500 rpm、5000 rpm或5500 rpm等。Preferably, the rotation speed of the spin coating is 2000-6000 rpm, for example, it can be 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, 5000 rpm or 5500 rpm, etc.
优选地，所述旋涂的时间为10-60 s，例如可以为15 s、20 s、25 s、30 s、35 s、40 s、45 s、50 s或55 s等。Preferably, the spin coating time is 10-60 s, for example, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s or 55 s, etc.
优选地，所述干燥的温度为80-120℃，例如可以为85℃、90℃、95℃、100℃、105℃、110℃或115℃等。Preferably, the drying temperature is 80-120°C, for example, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or 115°C.
优选地，所述干燥的时间为2-20 min，例如可以为3 min、5 min、7 min、9 min、10 min、12 min、15 min或18 min等。Preferably, the drying time is 2-20 min, for example, 3 min, 5 min, 7 min, 9 min, 10 min, 12 min, 15 min or 18 min, etc.
有益效果Beneficial Effects
相对于现有技术，本发明具有以下有益效果：Compared with the prior art, the present invention has the following beneficial effects:
（1）本发明提供的全无机钙钛矿光敏层的制备方法为包含丝网印刷的低温液相法工艺，条件温和、工艺简单、可操作性强，能够在导电基底或像素芯片上直接原位生长得到钙钛矿厚膜，实现材料与导电基底/像素芯片良好的键合集成，具有规模化制备的潜力，为探测成像提供工艺基础。(1) The preparation method of the all-inorganic perovskite photosensitive layer provided by the present invention is a low-temperature liquid phase process including screen printing, which has mild conditions, simple process, strong operability, and can directly grow a thick perovskite film in situ on a conductive substrate or a pixel chip, thereby achieving good bonding integration between the material and the conductive substrate/pixel chip. It has the potential for large-scale preparation and provides a process basis for detection imaging.
（2）所述制备方法得到的全无机钙钛矿光敏层具有大面积、致密均匀和平整度高的特点，钙钛矿的结晶度高，晶体缺陷少，晶体质量好，具有优异的环境湿度稳定性和热稳定性，能够充分吸收转化高能X/γ射线。(2) The all-inorganic perovskite photosensitive layer obtained by the preparation method has the characteristics of large area, dense uniformity and high flatness. The perovskite has high crystallinity, few crystal defects, good crystal quality, excellent environmental humidity stability and thermal stability, and can fully absorb and convert high-energy X/γ rays.
（3）包含所述全无机钙钛矿光敏层的X射线探测器具有优异的光电性能和稳定性，其暗电流降低，器件的老化稳定性和载流子传输性能有效提升，所述X射线探测器在灵敏度和稳定性方面具有明显改善，信噪比降低，有良好的应用前景。(3) The X-ray detector containing the all-inorganic perovskite photosensitive layer has excellent photoelectric performance and stability, its dark current is reduced, and the aging stability and carrier transport performance of the device are effectively improved. The X-ray detector has obvious improvements in sensitivity and stability, and the signal-to-noise ratio is reduced, and has good application prospects.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
图1为实施例1中步骤（3）的工艺流程图，其中，1-钙钛矿前驱体浆料，2-刮刀，3-丝网版，4-网框，5-基板，6-承印台；FIG1 is a process flow chart of step (3) in Example 1, wherein: 1-perovskite precursor slurry, 2-scraper, 3-screen, 4-screen frame, 5-substrate, 6-printing platform;
图2为实施例1所述全无机钙钛矿光敏层的光学图；FIG2 is an optical image of the all-inorganic perovskite photosensitive layer described in Example 1;
图3为实施例1所述全无机钙钛矿光敏层的SEM表面形貌图；FIG3 is a SEM surface morphology of the all-inorganic perovskite photosensitive layer described in Example 1;
图4为实施例1所述全无机钙钛矿光敏层的SEM截面形貌图；FIG4 is a SEM cross-sectional morphology of the all-inorganic perovskite photosensitive layer described in Example 1;
图5为实施例2所述X射线探测器的结构示意图，其中，10-导电基底，20-钙钛矿光敏层，30-电子传输层，40-背电极；FIG5 is a schematic diagram of the structure of the X-ray detector described in Example 2, wherein 10 is a conductive substrate, 20 is a perovskite photosensitive layer, 30 is an electron transport layer, and 40 is a back electrode;
图6为实施例2所述X射线探测器的I-V曲线图；FIG6 is an I-V curve diagram of the X-ray detector described in Example 2;
图7为实施例2所述X射线探测器在不同电场强度下的灵敏度测试图；FIG7 is a sensitivity test diagram of the X-ray detector of Example 2 under different electric field strengths;
图8为实施例2所述X射线探测器的最低可探测X射线剂量的结果图。FIG8 is a result diagram of the minimum detectable X-ray dose of the X-ray detector described in Example 2.
本发明的实施方式Embodiments of the present invention
下面通过具体实施方式来进一步说明本发明的技术方案。本领域技术人员应该明了，所述实施例仅仅是帮助理解本发明，不应视为对本发明的具体限制。The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.
本发明以下具体实施方式中，所涉及的原料和试剂均为市售商品，例如松油醇（阿拉丁，CAS号为8000-41-7）；乙基纤维素（阿拉丁，CAS号为9004-57-3）。In the following specific embodiments of the present invention, the raw materials and reagents involved are all commercially available products, such as terpineol (Aladdin, CAS No. 8000-41-7); ethyl cellulose (Aladdin, CAS No. 9004-57-3).
实施例1Example 1
一种全无机钙钛矿（CsPbBr 3）光敏层及其制备方法，所述制备方法包括如下步骤： A fully inorganic perovskite (CsPbBr 3 ) photosensitive layer and a preparation method thereof, the preparation method comprising the following steps:
（1）将CsBr和PbBr 2以摩尔比1:1混合均匀，然后放入玛瑙球磨罐，行星球磨获得CsPbBr 3钙钛矿粉末；所述球磨的球料比为1:5，转速为200 rpm，时间为1 h； (1) CsBr and PbBr2 were mixed evenly in a molar ratio of 1:1, and then placed in an agate ball mill, and planetary ball milled to obtain CsPbBr3 perovskite powder; the ball-to-material ratio of the ball mill was 1:5, the rotation speed was 200 rpm, and the time was 1 h;
（2）步骤（1）得到的CsPbBr 3钙钛矿粉末置于研钵中，加入有机溶剂（DMF与DMSO体积比为1:1的混合溶剂），CsPbBr 3钙钛矿粉末与有机溶剂的质量比为4:1；再加入松油醇（松油醇与有机溶剂的体积比为1:6）作为反溶剂，加入乙基纤维素（乙基纤维素与CsPbBr 3钙钛矿粉末的质量比为1:15）作为增稠剂，将其研磨1 h，混合均匀，得到钙钛矿前驱体浆料，其固含量为80%； (2) The CsPbBr3 perovskite powder obtained in step (1) is placed in a mortar, and an organic solvent (a mixed solvent of DMF and DMSO in a volume ratio of 1:1) is added, and the mass ratio of CsPbBr3 perovskite powder to the organic solvent is 4:1; then pineneol (the volume ratio of pineneol to the organic solvent is 1:6) is added as an anti-solvent, and ethyl cellulose (the mass ratio of ethyl cellulose to CsPbBr3 perovskite powder is 1:15) is added as a thickener, and the mixture is ground for 1 h and mixed evenly to obtain a perovskite precursor slurry with a solid content of 80%;
（3）步骤（2）得到的钙钛矿前驱体浆料进行丝网印刷和退火，形成所述全无机钙钛矿光敏层；(3) Screen printing and annealing the perovskite precursor slurry obtained in step (2) to form the all-inorganic perovskite photosensitive layer;
步骤（3）的工艺流程图如图1所示，其中，1为钙钛矿前驱体浆料，2为刮刀，3为丝网版，4为网框，5为基板，6为承印台；丝网印刷的次数为3次，丝网孔径为300目，形成涂层；所述涂层首先在100℃退火10 min，溶剂逐渐挥发，钙钛矿结晶生长，再150℃退火30 min，得到厚度为300 μm的所述全无机钙钛矿光敏层。The process flow chart of step (3) is shown in Figure 1, wherein 1 is perovskite precursor slurry, 2 is a scraper, 3 is a screen plate, 4 is a screen frame, 5 is a substrate, and 6 is a printing table; the screen printing is performed 3 times, the screen aperture is 300 mesh, and a coating is formed; the coating is first annealed at 100°C for 10 min, the solvent gradually evaporates, and the perovskite crystals grow, and then annealed at 150°C for 30 min to obtain the all-inorganic perovskite photosensitive layer with a thickness of 300 μm.
本实施例提供的制备方法得到的所述全无机钙钛矿光敏层的光学图如图2所示；通过扫描电子显微镜（SEM，Zeiss Gemini SEM 300）测试所述全无机钙钛矿光敏层的形貌，实施例1所述全无机钙钛矿光敏层的SEM表面形貌图如图3所示，SEM截面形貌图如图4所示。结合图2、图3和图4可知，所述制备方法能够实现全无机钙钛矿光敏层的大面积制备，得到的全无机钙钛矿光敏层的表面致密平整，均匀性好，截面也展现出较为完整的形貌，保证充分吸收转化X射线。The optical image of the all-inorganic perovskite photosensitive layer obtained by the preparation method provided in this embodiment is shown in Figure 2; the morphology of the all-inorganic perovskite photosensitive layer was tested by scanning electron microscopy (SEM, Zeiss Gemini SEM 300), and the SEM surface morphology of the all-inorganic perovskite photosensitive layer in Example 1 is shown in Figure 3, and the SEM cross-sectional morphology is shown in Figure 4. Combining Figures 2, 3 and 4, it can be seen that the preparation method can achieve large-area preparation of the all-inorganic perovskite photosensitive layer, and the surface of the obtained all-inorganic perovskite photosensitive layer is dense and flat, with good uniformity, and the cross-section also shows a relatively complete morphology, ensuring sufficient absorption and conversion of X-rays.
实施例2Example 2
一种X射线探测器，其结构示意图如图5所示，包括依次设置的导电基底10、钙钛矿光敏层20、电子传输层30和背电极40；其中，导电基底10为ITO导电基底（ITO导电玻璃），钙钛矿光敏层20为实施例1所述制备方法得到的全无机钙钛矿光敏层（厚度为300 μm），电子传输层30为PCBM电子传输层（厚度为30 nm），背电极40为Au电极，厚度为100 nm。An X-ray detector, the structure of which is shown in FIG5 , comprises a conductive substrate 10, a perovskite photosensitive layer 20, an electron transport layer 30 and a back electrode 40 arranged in sequence; wherein the conductive substrate 10 is an ITO conductive substrate (ITO conductive glass), the perovskite photosensitive layer 20 is an all-inorganic perovskite photosensitive layer (thickness 300 μm) obtained by the preparation method described in Example 1, the electron transport layer 30 is a PCBM electron transport layer (thickness 30 nm), and the back electrode 40 is an Au electrode with a thickness of 100 nm.
所述X射线探测器的制备方法包括如下步骤：The method for preparing the X-ray detector comprises the following steps:
（1）用肥皂水、乙醇、丙酮依次清洗ITO导电玻璃；在ITO导电玻璃上采用实施例1提供的制备方法得到厚度为300 μm的全无机钙钛矿光敏层；(1) Cleaning the ITO conductive glass with soapy water, ethanol and acetone in sequence; and obtaining a 300 μm thick all-inorganic perovskite photosensitive layer on the ITO conductive glass using the preparation method provided in Example 1;
（2）将20 mg的PCBM溶解在1 mL的氯苯中，搅拌1 h，形成PCBM电子传输材料的均匀溶液；在步骤（1）得到的全无机钙钛矿光敏层上以4000 rpm的转速旋涂40 s所述均匀溶液，然后100℃干燥10 min，得到PCBM电子传输层；(2) Dissolve 20 mg of PCBM in 1 mL of chlorobenzene and stir for 1 h to form a uniform solution of PCBM electron transport material; spin coat the uniform solution on the all-inorganic perovskite photosensitive layer obtained in step (1) at a speed of 4000 rpm for 40 s, and then dry at 100°C for 10 min to obtain a PCBM electron transport layer;
（3）在步骤（2）得到的PCBM电子传输层上真空蒸镀Au电极，真空度为10 -6 mbar，蒸镀速率0.3 Å/s，形成厚度为100 nm的Au作为背电极，得到所述X射线探测器。 (3) Vacuum evaporating an Au electrode on the PCBM electron transport layer obtained in step (2) at a vacuum degree of 10 -6 mbar and an evaporation rate of 0.3 Å/s to form an Au back electrode with a thickness of 100 nm, thereby obtaining the X-ray detector.
对本实施例提供的X射线探测器进行如下性能测试：The following performance tests were performed on the X-ray detector provided in this embodiment:
（1）I-V曲线测试(1) I-V curve test
采用吉时利数字源表2700和X射线源（Rigaku Smartlab 3kW X-ray diffractometer with Cu Kα radiation）测试所述X射线探测器的电流-电压特性，得到的I-V曲线图如图6所示，横轴为电场（electrical field，单位为V/mm），纵轴为电流密度（current density，单位A/mm 2），其暗电流（dark current）的数值为10 -11-10 -9 A·mm -2，对应偏压下的光电流（light current）提高到了10 -9-10 -7 A·mm -2，有100倍以上的提升。 The current-voltage characteristics of the X-ray detector were tested using a Keithley SourceMeter 2700 and an X-ray source (Rigaku Smartlab 3kW X-ray diffractometer with Cu Kα radiation). The resulting IV curve is shown in FIG6 , where the horizontal axis represents the electric field (V/mm) and the vertical axis represents the current density (A/mm 2 ). The dark current value is 10 -11 -10 -9 A·mm -2 , and the corresponding light current under bias is increased to 10 -9 -10 -7 A·mm -2 , which is more than 100 times higher.
（2）灵敏度测试(2) Sensitivity test
采用吉时利数字源表2700和X射线源（Rigaku Smartlab 3kW X-ray diffractometer with Cu Kα radiation）测试所述X射线探测器在不同电场强度下的响应电流随X射线剂量的变化，从而分析获得探测器的灵敏度。具体地，所述X射线探测器在不同电场强度下的灵敏度测试图如图7所示，横轴为X射线的剂量率（dose rate，单位mG air/s），纵轴为响应电流密度（current density，单位μA/cm 2），曲线的斜率就是X射线探测器的灵敏度，所述X射线探测器在20 V/mm下的灵敏度为1547 μC·Gy air -1·cm -2，在40 V/mm下的灵敏度为4334 μC·Gy air -1·cm -2，在60 V/mm下的灵敏度为7266 μC·Gy air -1·cm -2，在80 V/mm下的灵敏度为9341 μC·Gy air -1·cm -2。 The response current of the X-ray detector under different electric field strengths was tested by using a Keithley source meter 2700 and an X-ray source (Rigaku Smartlab 3kW X-ray diffractometer with Cu Kα radiation) to change with the X-ray dose, so as to analyze and obtain the sensitivity of the detector. Specifically, the sensitivity test diagram of the X-ray detector under different electric field strengths is shown in FIG7 , where the horizontal axis is the X-ray dose rate (dose rate, unit: mG air /s), the vertical axis is the response current density (current density, unit: μA/cm 2 ), and the slope of the curve is the sensitivity of the X-ray detector. The sensitivity of the X-ray detector under 20 V/mm is 1547 μC·Gy air -1 ·cm -2 , the sensitivity under 40 V/mm is 4334 μC·Gy air -1 ·cm -2 , the sensitivity under 60 V/mm is 7266 μC·Gy air -1 ·cm -2 , and the sensitivity under 80 V/mm is 9341 μC·Gy air -1 ·cm -2 .
（3）最低可探测X射线剂量测试(3) Minimum detectable X-ray dose test
根据前述灵敏度测试数据计算所述X射线探测器的最低可探测X射线的剂量，得到的结果图如图8所示，横轴为X射线的剂量率（dose rate，单位μGy air/s），纵轴为信噪比（SNR），SNR等于光电流（I light）减去暗电流（I dark）再除以电流噪声（I noise）的比值，即SNR=（I light - I dark）/I noise，所述X射线探测器的最低可探测X射线的剂量为588 n Gy air·s -1，此时器件的信噪比（SNR）等于3。 The minimum detectable X-ray dose of the X-ray detector is calculated according to the aforementioned sensitivity test data, and the result graph is shown in FIG8 , where the horizontal axis is the X-ray dose rate (dose rate, in μGy air /s), and the vertical axis is the signal-to-noise ratio (SNR), where SNR is equal to the ratio of photocurrent (I light ) minus dark current (I dark ) divided by current noise (I noise ), that is, SNR= (I light - I dark )/I noise . The minimum detectable X-ray dose of the X-ray detector is 588 n Gy air ·s -1 , and the signal-to-noise ratio (SNR) of the device is equal to 3.
实施例3-4Embodiment 3-4
一种全无机钙钛矿光敏层及其制备方法，其与实施例1的区别仅在于，实施例3为CsPbCl 2Br光敏层，步骤（1）的原料为摩尔比1:1的CsBr和PbCl 2；实施例4为CsPbClBr 2光敏层，步骤（1）的原料为摩尔比1:1的CsCl和PbBr 2；其他物料、配比和制备方法均与实施例1相同，得到全无机钙钛矿光敏层。 An all-inorganic perovskite photosensitive layer and a preparation method thereof, which differs from Example 1 only in that Example 3 is a CsPbCl 2 Br photosensitive layer, and the raw materials of step (1) are CsBr and PbCl 2 in a molar ratio of 1:1; Example 4 is a CsPbClBr 2 photosensitive layer, and the raw materials of step (1) are CsCl and PbBr 2 in a molar ratio of 1:1; other materials, proportions and preparation methods are the same as those in Example 1, and an all-inorganic perovskite photosensitive layer is obtained.
一种X射线探测器，其与实施例2的仅在于，钙钛矿光敏层为前述全无机钙钛矿光敏层；其他层级结构、材料和制备方法均与实施例2相同。An X-ray detector, which is the same as Example 2 only in that the perovskite photosensitive layer is the aforementioned all-inorganic perovskite photosensitive layer; the other hierarchical structures, materials and preparation methods are the same as those of Example 2.
采用实施例2中相同的测试方法对所述X射线探测器进行探测灵敏度（80 V/mm）和最低可探测剂量的性能测试，测试结果如表1所示：The same test method as in Example 2 was used to perform performance tests on the detection sensitivity (80 V/mm) and the minimum detectable dose of the X-ray detector. The test results are shown in Table 1:
表1Table 1
结合表1的性能测试数据可知，本发明提供的制备方法可用于不同全无机钙钛矿光敏层的制备，进而获得不同的X射线探测器；其中，包含实施例1中CsPbBr 3光敏层的X射线探测器具有更优的灵敏度。 Combined with the performance test data in Table 1, it can be seen that the preparation method provided by the present invention can be used to prepare different all-inorganic perovskite photosensitive layers, thereby obtaining different X-ray detectors; among them, the X-ray detector comprising the CsPbBr3 photosensitive layer in Example 1 has better sensitivity.
实施例5Example 5
一种全无机钙钛矿（CsPbBr 3）光敏层及其制备方法，其与实施例1的区别仅在于，将步骤（2）中的有机溶剂替换为如表2所示的体积比；其他物料、配比和制备方法均与实施例1相同，得到全无机钙钛矿光敏层。 An all-inorganic perovskite (CsPbBr 3 ) photosensitive layer and a preparation method thereof, which differs from Example 1 only in that the organic solvent in step (2) is replaced by a volume ratio as shown in Table 2; other materials, proportions and preparation methods are the same as those in Example 1, to obtain an all-inorganic perovskite photosensitive layer.
一种X射线探测器，其与实施例2的仅在于，钙钛矿光敏层为前述全无机钙钛矿光敏层；其他层级结构、材料和制备方法均与实施例2相同。An X-ray detector, which is the same as Example 2 only in that the perovskite photosensitive layer is the aforementioned all-inorganic perovskite photosensitive layer; the other hierarchical structures, materials and preparation methods are the same as those of Example 2.
采用实施例2中相同的测试方法对所述X射线探测器进行探测灵敏度（80 V/mm）和最低可探测剂量的性能测试，测试结果如表2所示：The same test method as in Example 2 was used to perform performance tests on the detection sensitivity (80 V/mm) and the minimum detectable dose of the X-ray detector. The test results are shown in Table 2:
表2Table 2
结合表2的性能测试数据可知，通过制备方法中有机溶剂的配比优化，有助于钙钛矿材料微晶的再生长，获得高质量的全无机钙钛矿光敏层，进而提高X射线探测器的灵敏度，获得更低的最低探测剂量。Combined with the performance test data in Table 2, it can be seen that by optimizing the ratio of organic solvents in the preparation method, it is helpful to regrow the microcrystals of the perovskite material, obtain a high-quality all-inorganic perovskite photosensitive layer, and then improve the sensitivity of the X-ray detector and obtain a lower minimum detection dose.
实施例6Example 6
一种全无机钙钛矿（CsPbBr 3）光敏层及其制备方法，其与实施例1的区别仅在于，调整步骤（3）中丝网印刷的次数，获得如表3所示厚度的全无机钙钛矿光敏层；其他物料、配比和制备方法均与实施例1相同，得到全无机钙钛矿光敏层。 An all-inorganic perovskite (CsPbBr 3 ) photosensitive layer and a preparation method thereof, which differs from Example 1 only in that the number of screen printing in step (3) is adjusted to obtain an all-inorganic perovskite photosensitive layer with a thickness as shown in Table 3; other materials, proportions and preparation methods are the same as those in Example 1 to obtain an all-inorganic perovskite photosensitive layer.
一种X射线探测器，其与实施例2的仅在于，钙钛矿光敏层为前述全无机钙钛矿光敏层；其他层级结构、材料和制备方法均与实施例2相同。An X-ray detector, which is the same as Example 2 only in that the perovskite photosensitive layer is the aforementioned all-inorganic perovskite photosensitive layer; the other hierarchical structures, materials and preparation methods are the same as those of Example 2.
采用实施例2中相同的测试方法对所述X射线探测器进行探测灵敏度（80 V/mm）和最低可探测剂量的性能测试，测试结果如表3所示：The same test method as in Example 2 was used to perform performance tests on the detection sensitivity (80 V/mm) and the minimum detectable dose of the X-ray detector. The test results are shown in Table 3:
表3table 3
结合表3的性能测试数据可知，本发明提供的制备方法中，通过控制丝网印刷的次数，能够获得厚度为100-450 μm的全无机钙钛矿光敏层，钙钛矿的结晶度高，晶体缺陷少、质量好，能够充分吸收转化高能X射线，使X射线探测器具有优异的稳定性和灵敏度。Combined with the performance test data in Table 3, it can be seen that in the preparation method provided by the present invention, by controlling the number of screen printing, an all-inorganic perovskite photosensitive layer with a thickness of 100-450 μm can be obtained, the perovskite has high crystallinity, few crystal defects, good quality, can fully absorb and convert high-energy X-rays, and the X-ray detector has excellent stability and sensitivity.
申请人声明，本发明通过上述实施例来说明本发明的全无机钙钛矿光敏层及其制备方法和应用，但本发明并不局限于上述工艺步骤，即不意味着本发明必须依赖上述工艺步骤才能实施。所属技术领域的技术人员应该明了，对本发明的任何改进，对本发明所选用原料的等效替换及辅助成分的添加、具体方式的选择等，均落在本发明的保护范围和公开范围之内。The applicant declares that the present invention illustrates the all-inorganic perovskite photosensitive layer and its preparation method and application through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims (10)

  1. 一种全无机钙钛矿光敏层的制备方法，其特征在于，所述全无机钙钛矿光敏层的厚度≥90 μm；所述制备方法包括如下步骤：A method for preparing an all-inorganic perovskite photosensitive layer, characterized in that the thickness of the all-inorganic perovskite photosensitive layer is ≥ 90 μm; the preparation method comprises the following steps:
    （1）将无机卤化物AX与无机卤化物BY 2进行研磨，得到钙钛矿材料ABXY 2；所述A为Cs、Bi或Rb，所述B为Pb、Sn或Ge，所述X、Y各自独立地为卤素； (1) grinding an inorganic halide AX and an inorganic halide BY 2 to obtain a perovskite material ABXY 2 ; A is Cs, Bi or Rb, B is Pb, Sn or Ge, and X and Y are each independently a halogen;
    （2）步骤（1）得到的钙钛矿材料ABXY 2与有机溶剂混合，得到钙钛矿前驱体浆料； (2) The perovskite material ABXY2 obtained in step (1) is mixed with an organic solvent to obtain a perovskite precursor slurry;
    （3）步骤（2）得到的钙钛矿前驱体浆料通过丝网印刷形成涂层，所述涂层经过退火，得到所述全无机钙钛矿光敏层。(3) The perovskite precursor slurry obtained in step (2) is formed into a coating by screen printing, and the coating is annealed to obtain the all-inorganic perovskite photosensitive layer.
  2. 根据权利要求1所述的制备方法，其特征在于，所述A为Cs；The preparation method according to claim 1, characterized in that A is Cs;
    优选地，所述B为Pb；优选地，所述X和Y各自独立地为Cl、Br或I，进一步优选为Cl或Br；优选地，所述无机卤化物AX与无机卤化物BY 2的摩尔比为1:(0.5-2)。 Preferably, B is Pb; preferably, X and Y are each independently Cl, Br or I, more preferably Cl or Br; preferably, the molar ratio of the inorganic halide AX to the inorganic halide BY 2 is 1:(0.5-2).
  3. 根据权利要求1或2所述的制备方法，其特征在于，步骤（1）所述研磨的方法为球磨；The preparation method according to claim 1 or 2, characterized in that the grinding method in step (1) is ball milling;
    优选地，所述球磨的球料比为1:(1-5)；优选地，所述球磨的转速为200-1000 rpm；优选地，所述球磨的时间为0.5-6 h。Preferably, the ball-to-material ratio of the ball mill is 1:(1-5); preferably, the rotation speed of the ball mill is 200-1000 rpm; preferably, the ball milling time is 0.5-6 h.
  4. 根据权利要求1-3任一项所述的制备方法，其特征在于，步骤（2）所述有机溶剂包括二甲基亚砜、 N,N-二甲基甲酰胺、 N,N-二甲基乙酰胺或γ-丁内酯中的任意一种或至少两种的组合，优选二甲基亚砜和 N,N-二甲基甲酰胺的组合； The preparation method according to any one of claims 1 to 3, characterized in that the organic solvent in step (2) comprises any one of dimethyl sulfoxide, N,N -dimethylformamide, N,N -dimethylacetamide or γ-butyrolactone or a combination of at least two thereof, preferably a combination of dimethyl sulfoxide and N,N -dimethylformamide;
    优选地，所述二甲基亚砜与 N,N-二甲基甲酰胺的体积比为(0.5-5):1；优选地，步骤（2）所述钙钛矿材料ABXY 2与有机溶剂的质量比为(3-5):1；优选地，步骤（2）所述混合的物料还包括粘度调节剂；优选地，所述粘度调节剂包括松油醇和/或纤维素；优选地，所述纤维素包括乙基纤维素；优选地，所述松油醇与有机溶剂的体积比为1:(4-8)；优选地，所述纤维素与钙钛矿材料ABXY 2的质量比为1:(10-20)；优选地，步骤（2）所述混合后还包括研磨的步骤；优选地，所述研磨的时间为0.5-3 h；优选地，步骤（2）所述钙钛矿前驱体浆料的固含量为70-90%。 Preferably, the volume ratio of dimethyl sulfoxide to N,N -dimethylformamide is (0.5-5):1; preferably, the mass ratio of the perovskite material ABXY2 to the organic solvent in step (2) is (3-5):1; preferably, the mixed material in step (2) further comprises a viscosity modifier; preferably, the viscosity modifier comprises pinene alcohol and/or cellulose; preferably, the cellulose comprises ethyl cellulose; preferably, the volume ratio of pinene alcohol to the organic solvent is 1:(4-8); preferably, the mass ratio of the cellulose to the perovskite material ABXY2 is 1:(10-20); preferably, the step (2) further comprises a grinding step after the mixing; preferably, the grinding time is 0.5-3 h; preferably, the solid content of the perovskite precursor slurry in step (2) is 70-90%.
  5. 根据权利要求1-4任一项所述的制备方法，其特征在于，步骤（3）所述丝网印刷的次数为1-5次；The preparation method according to any one of claims 1 to 4, characterized in that the number of screen printing in step (3) is 1 to 5 times;
    优选地，步骤（3）所述丝网印刷的丝网孔径为200-500目；优选地，步骤（3）所述退火的温度为80-150℃；优选地，步骤（3）所述退火的时间为0.5-2 h；优选地，步骤（3）所述退火包括依次进行的第一阶段退火和第二阶段退火；所述第一阶段退火的温度为80-120℃，时间为10-40 min；所述第二阶段退火的温度为125-150℃，时间为20-80 min。Preferably, the aperture of the screen printing in step (3) is 200-500 mesh; preferably, the annealing temperature in step (3) is 80-150°C; preferably, the annealing time in step (3) is 0.5-2 h; preferably, the annealing in step (3) includes a first stage annealing and a second stage annealing performed sequentially; the first stage annealing temperature is 80-120°C and the time is 10-40 min; the second stage annealing temperature is 125-150°C and the time is 20-80 min.
  6. 根据权利要求1-5任一项所述的制备方法，其特征在于，所述全无机钙钛矿光敏层的厚度≥90 μm，所述制备方法具体包括如下步骤：The preparation method according to any one of claims 1 to 5, characterized in that the thickness of the all-inorganic perovskite photosensitive layer is ≥ 90 μm, and the preparation method specifically comprises the following steps:
    （1）将无机卤化物AX与无机卤化物BY 2以摩尔比1:(0.5-2)混合后进行球磨，得到钙钛矿材料ABXY 2；所述A为Cs、Bi或Rb，所述B为Pb、Sn或Ge，所述X和Y各自独立地为卤素；所述球磨的球料比为1:(1-5)，转速为200-1000 rpm，时间为0.5-6 h； (1) Mixing an inorganic halide AX and an inorganic halide BY2 in a molar ratio of 1:(0.5-2) and ball milling to obtain a perovskite material ABXY2 ; wherein A is Cs, Bi or Rb, B is Pb, Sn or Ge, and X and Y are independently halogens; the ball-to-material ratio of the ball milling is 1:(1-5), the rotation speed is 200-1000 rpm, and the time is 0.5-6 h;
    （2）步骤（1）得到的钙钛矿材料ABXY 2与有机溶剂混合并研磨，得到钙钛矿前驱体浆料；所述有机溶剂包括体积比为(0.5-5):1的二甲基亚砜和 N,N-二甲基甲酰胺；所述钙钛矿材料ABXY 2与有机溶剂的质量比为(3-5):1； (2) The perovskite material ABXY2 obtained in step (1) is mixed with an organic solvent and ground to obtain a perovskite precursor slurry; the organic solvent comprises dimethyl sulfoxide and N,N -dimethylformamide in a volume ratio of (0.5-5):1; the mass ratio of the perovskite material ABXY2 to the organic solvent is (3-5):1;
    （3）步骤（2）得到的钙钛矿前驱体浆料通过丝网印刷形成涂层，所述涂层依次进行第一阶段退火和第二阶段退火，得到所述全无机钙钛矿光敏层；所述第一阶段退火的温度为80-120℃，时间为10-40 min；所述第二阶段退火的温度为125-150℃，时间为20-80 min。(3) The perovskite precursor slurry obtained in step (2) is formed into a coating by screen printing, and the coating is subjected to a first stage annealing and a second stage annealing in sequence to obtain the all-inorganic perovskite photosensitive layer; the temperature of the first stage annealing is 80-120°C and the time is 10-40 min; the temperature of the second stage annealing is 125-150°C and the time is 20-80 min.
  7. 一种全无机钙钛矿光敏层，其特征在于，所述全无机钙钛矿光敏层通过如权利要求1-6任一项所述的制备方法制备得到；An all-inorganic perovskite photosensitive layer, characterized in that the all-inorganic perovskite photosensitive layer is prepared by the preparation method according to any one of claims 1 to 6;
    优选地，所述全无机钙钛矿光敏层的厚度为90-500 μm。Preferably, the thickness of the all-inorganic perovskite photosensitive layer is 90-500 μm.
  8. 一种如权利要求7所述的全无机钙钛矿光敏层在钙钛矿电池或钙钛矿探测器件中的应用；An application of the all-inorganic perovskite photosensitive layer as claimed in claim 7 in a perovskite cell or a perovskite detection device;
    优选地，所述钙钛矿探测器件为X射线探测器。Preferably, the perovskite detection device is an X-ray detector.
  9. 一种X射线探测器，其特征在于，所述X射线探测器包括导电基底、钙钛矿光敏层、传输层和背电极；所述钙钛矿光敏层为权利要求7所述的全无机钙钛矿光敏层；An X-ray detector, characterized in that the X-ray detector comprises a conductive substrate, a perovskite photosensitive layer, a transmission layer and a back electrode; the perovskite photosensitive layer is the all-inorganic perovskite photosensitive layer according to claim 7;
    优选地，所述导电基底包括ITO导电基底、FTO导电基体、TFT像素芯片或CMOS像素芯片；优选地，所述传输层为电子传输层；优选地，所述X射线探测器包括依次设置的导电基底、所述全无机钙钛矿光敏层、电子传输层和背电极；优选地，所述电子传输层包括富勒烯衍生物电子传输层，进一步优选PCBM电子传输层；优选地，所述电子传输层的厚度为1-100 nm；优选地，所述背电极包括Au电极；优选地，所述背电极的厚度为50-200 nm。Preferably, the conductive substrate comprises an ITO conductive substrate, an FTO conductive substrate, a TFT pixel chip or a CMOS pixel chip; preferably, the transport layer is an electron transport layer; preferably, the X-ray detector comprises a conductive substrate, the all-inorganic perovskite photosensitive layer, an electron transport layer and a back electrode arranged in sequence; preferably, the electron transport layer comprises a fullerene derivative electron transport layer, and more preferably a PCBM electron transport layer; preferably, the thickness of the electron transport layer is 1-100 nm; preferably, the back electrode comprises an Au electrode; preferably, the thickness of the back electrode is 50-200 nm.
  10. 一种如权利要求9所述的X射线探测器的制备方法，其特征在于，所述制备方法包括：A method for preparing an X-ray detector according to claim 9, characterized in that the preparation method comprises:
    采用如权利要求1-6任一项所述的制备方法在导电基底的导电层上制备全无机钙钛矿光敏层；The all-inorganic perovskite photosensitive layer is prepared on the conductive layer of the conductive substrate by the preparation method according to any one of claims 1 to 6;
    在所述全无机钙钛矿光敏层上依次涂布电子传输层材料、干燥、真空蒸镀背电极材料，得到所述X射线探测器。The electron transport layer material is sequentially coated on the all-inorganic perovskite photosensitive layer, dried, and vacuum evaporated to obtain the X-ray detector.
PCT/CN2022/137081 2022-11-08 2022-12-06 All-inorganic perovskite photosensitive layer, and preparation method therefor and use thereof WO2024098487A1 (en)

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