A perovskite radiation detector based on Schottky junction and its preparation method

Abstract

The present disclosure provides a method for preparing a perovskite radiation detector based on a Schottky junction, comprising: applying a carbon slurry to a first substrate by scraping to form a film, and subjecting the film to annealing to obtain a carbon electrode layer; applying the carbon slurry to a second substrate by scraping to form a film, soaking the film in an organic solvent for more than 10 minutes, peeling the carbon film from the second substrate, and allowing the film to stand in air until the organic solvent is completely volatilized to obtain a porous carbon film; dissolving an organic ammonium salt or a cesium salt and a metal halide in a polar organic solvent to obtain a perovskite solution, pouring the perovskite solution onto the porous carbon film, allowing the perovskite solution to penetrate the porous carbon film under pressure, and subjecting the film to annealing to obtain a radiation absorption layer composed of a porous carbon-perovskite composite material; pressing the radiation absorption layer and the carbon electrode layer; and sequentially preparing a perovskite layer, a hole injection layer, and a top electrode layer on the radiation absorption layer to obtain a perovskite radiation detector based on a Schottky junction.

Description

Technical Field

[0001] The present disclosure belongs to the field of radiation detection, and specifically relates to a Schottky structure-based perovskite radiation detector and a preparation method thereof. Background Art

[0002] A radiation detector is a sensor device used to observe and study the microscopic phenomena of nuclear radiation and particles. Its operating principle is based on the interaction between particles and matter. X-ray detectors, as a type of radiation detector, convert X-rays into digital signals that can ultimately be transformed into images. Consequently, they are widely used in medical diagnosis, radiotherapy, deep space exploration, geological prospecting, industrial non-destructive testing, and environmental radiation monitoring.

[0003] Perovskite radiation detectors have developed rapidly in recent years. Semiconductor radiation detectors based on solution-grown perovskite single crystals have far surpassed the performance of traditional semiconductor radiation detectors such as amorphous selenium and mercuric iodide. Currently, perovskite radiation detectors use a traditional layered structure, in which photogenerated carriers must migrate across the thickness of the device to achieve high detection sensitivity. This typically requires an operating voltage of tens to hundreds of volts. However, higher operating voltages exacerbate ion migration, reduce device stability, and limit the application of perovskite semiconductor radiation detectors in portable radiation detection devices.

[0004] In addition, there are other urgent problems to be solved in the development of perovskite semiconductor radiation detectors. For example, the perovskite single crystal material prepared by the solution growth method limits the size of the radiation absorption layer, and it is still relatively difficult to prepare large-area, high-quality perovskite X-ray absorption layers, which affects the sensitivity, low-dose detection capability, and spatial resolution of the radiation detector; the perovskite material is easily decomposed when in contact with water and oxygen, resulting in poor device stability.

[0005] Therefore, exploring a new type of radiation perovskite radiation detector that can simultaneously meet the requirements of large-area preparation, high stability, high detection performance, and low operating voltage has far-reaching significance and practical value. Summary of the Invention

[0006] In view of this, in order to overcome the technical problem that the size of traditional perovskite radiation detectors is limited by their crystallization properties, and at the same time develop radiation detectors with high stability and high detection performance at low operating voltages, the present disclosure proposes a perovskite radiation detector based on a Schottky junction and a preparation method thereof.

[0007] In one aspect of the present disclosure, a method for preparing a Schottky junction-based perovskite radiation detector is proposed, comprising:

[0008] The carbon slurry is coated on the first substrate to form a film, and then annealed to obtain a carbon electrode layer;

[0009] The carbon slurry is coated on a second substrate to form a film, which is then immersed in an organic solvent for more than 10 minutes. The carbon film is peeled off from the second substrate and allowed to stand in air until the organic solvent is completely evaporated, thereby obtaining a porous carbon film.

[0010] dissolving an organic ammonium salt or a cesium salt and a metal halide in a polar organic solvent to obtain a perovskite solution, pouring the perovskite solution onto a porous carbon film, allowing the perovskite solution to penetrate into the porous carbon film under pressure, and annealing to obtain a radiation absorption layer composed of a porous carbon-perovskite composite material;

[0011] placing a radiation absorbing layer on the carbon electrode layer, and combining the radiation absorbing layer and the carbon electrode layer under pressure;

[0012] The perovskite solution is coated on the radiation absorption layer and annealed to obtain a dense perovskite layer;

[0013] coating an organic hole injection material on the dense perovskite layer to obtain a hole injection layer;

[0014] A conductive metal is formed on the hole injection layer by thermal evaporation to form a top electrode layer, thereby obtaining a perovskite radiation detector based on a Schottky junction.

[0015] According to an embodiment of the present disclosure, the carbon slurry is scraped onto the first substrate to form a film, and the annealing treatment conditions include: the annealing temperature range includes 100-120° C., and the annealing time range includes 10-30 minutes.

[0016] According to an embodiment of the present disclosure, the metal halide includes one or more of lead iodide, tin iodide, copper iodide, manganese iodide, lead bromide, tin bromide, copper bromide, manganese bromide, lead chloride, tin chloride, copper chloride, and manganese chloride;

[0017] The organic ammonium salt includes one or more of methylammonium iodide, formamidine iodide, methylammonium bromide, formamidine bromide, methylammonium chloride, and formamidine chloride;

[0018] The cesium salt includes one or more of cesium iodide, cesium bromide, and cesium chloride;

[0019] The stoichiometric ratio of the organic ammonium salt (or cesium salt) to the metal halide ranges from 2:1 to 1:1.

[0020] According to the embodiment of the present disclosure, during the infiltration of the perovskite solution into the porous carbon film, the pressure conditions include 1.1 to 5 bar, the annealing treatment conditions include: the annealing temperature range includes 80 to 180° C., and the annealing time range includes 2 to 10 hours.

[0021] According to an embodiment of the present disclosure, during the bonding process between the radiation absorbing layer and the carbon electrode layer, the pressure conditions include a pressure range greater than 0.01 MPa;

[0022] The perovskite solution is coated on the radiation absorption layer and annealed under conditions including: an annealing temperature range of 50 to 180° C. and an annealing time range of 5 to 30 minutes.

[0023] According to an embodiment of the present disclosure, the organic hole injection material includes one of the following: polytriphenylamine, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and polyvinylcarbazole.

[0024] In another aspect of the present disclosure, a Schottky junction-based perovskite radiation detector prepared by the above method is provided, comprising:

[0025] A carbon electrode layer, used to conduct holes to output electrical signals;

[0026] a radiation absorbing layer formed on the carbon electrode layer, the radiation absorbing layer being prepared from a porous carbon-perovskite composite material and having a Schottky junction capable of forming a built-in electric field for generating carriers in response to X-rays;

[0027] A dense perovskite layer is formed on the radiation absorption layer to isolate the radiation absorption layer from the hole injection layer and prevent leakage of the radiation detector;

[0028] a hole injection layer formed on the dense perovskite layer, for injecting holes to maintain electrical neutrality of the internal structure of the perovskite radiation detector and form a circuit; and

[0029] The top electrode layer is formed on the hole injection layer and is used to receive an external bias to guide the carriers generated by the radiation absorption layer to move toward the carbon electrode layer, thereby assisting in extracting the carriers generated by the radiation absorption layer.

[0030] According to an embodiment of the present disclosure, the carriers generated by the radiation absorbing layer include photogenerated holes and photogenerated electrons.

[0031] According to the embodiment of the present disclosure, holes are extracted by the carbon electrode layer under the action of the built-in electric field of the Schottky junction, and photogenerated electrons are confined in the radiation absorption layer due to the obstruction of the Schottky junction.

[0032] In another aspect of the present disclosure, a perovskite radiation detection array is proposed, comprising a plurality of uniformly distributed radiation detectors as described above.

[0033] According to embodiments of the present disclosure, a Schottky junction-based perovskite radiation detector and its preparation method are proposed. By preparing a porous carbon-perovskite composite material, a radiation absorption layer with a Schottky junction is constructed. This is not limited by the size of the perovskite single crystal material, allowing the production of a large-area radiation absorption layer with good uniformity and spatial resolution. Furthermore, the present disclosure utilizes a simple preparation method to produce a perovskite radiation detector with stable operating performance and excellent detection and resolution.

[0034] According to embodiments of the present disclosure, the radiation detector proposed herein comprises a porous carbon-perovskite composite material with a Schottky junction as the radiation absorption layer. This improves the detection performance of the radiation detector while reducing its operating voltage, resulting in the perovskite radiation detector having excellent performance and stability. The low operating voltage enables the porous structure of the radiation detector to be applied to portable devices, enabling faster and more accurate portable radiation detection. Furthermore, the large-area, uniform porous carbon-perovskite radiation detection array exhibits excellent uniformity and spatial resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a diagram comparing the device structures and operating principles of a traditional layered semiconductor radiation detector and the Schottky junction-based perovskite radiation detector disclosed herein;

[0036] Figure 2 is a flow chart for preparing a Schottky junction-based perovskite radiation detector in the present disclosure;

[0037] Figure 3 is a scanning electron microscope image of the surface morphology of the porous carbon film prepared in the embodiment of the present disclosure;

[0038] Figure 4 is a scanning electron microscope image of the cross-sectional morphology of the porous carbon film prepared in the embodiment of the present disclosure;

[0039] Figure 5 is a scanning electron microscope image of the surface morphology of the porous carbon-perovskite composite material prepared in the embodiment of the present disclosure;

[0040] Figure 6 is a scanning electron microscope image of the cross-sectional morphology of the porous carbon-perovskite composite material prepared in the embodiment of the present disclosure;

[0041] Figure 7 Schematic diagram of the structure of the Schottky junction-based perovskite radiation detector prepared in the present disclosure;

[0042] Figure 8 is a diagram of the carrier separation phenomenon observed on a porous carbon-perovskite composite material using a Kelvin probe force microscope in the present disclosure;

[0043] Figure 9 is a graph showing the sensitivity change of the Schottky junction-based perovskite radiation detector under different bias voltages in the present disclosure;

[0044] Figure 10 This is a graph showing the sensitivity change of a traditional layered perovskite radiation detector under different bias voltages;

[0045] Figure 11 is a comparison chart of the signal-to-noise ratio of the Schottky junction-based perovskite radiation detector disclosed in the present invention and the traditional layered structure perovskite radiation detector;

[0046] Figure 12 is a current drift test graph of the Schottky junction-based perovskite radiation detector disclosed in the present invention;

[0047] Figure 13 This is a test diagram of the irradiation stability of the Schottky junction-based perovskite radiation detector disclosed in the present invention;

[0048] Figure 14 This is a graph showing the working stability of the Schottky junction-based perovskite radiation detector under pulsed X-rays in the present disclosure;

[0049] Figure 15 This is a long-term stability test graph of the Schottky junction-based perovskite radiation detector in the present disclosure stored in a nitrogen glove box environment;

[0050] Figure 16 This is a schematic diagram of the structure of the radiation alarm device prepared in Example 1 of the present disclosure;

[0051] Figure 17 This is a comparison chart of the response time between the radiation alarm prepared in Example 1 of the present disclosure and the radiation alarm based on the GM counter tube;

[0052] Figure 18 This is a comparison chart of the energy responses of the radiation alarm prepared in Example 1 of the present disclosure and the radiation alarm based on the GM counter tube to low-energy X-rays;

[0053] Figure 19 This is a dark current distribution diagram of different detection pixels of the perovskite radiation detection array prepared in Example 2 of the present disclosure in a dark environment;

[0054] Figure 20 This is a photocurrent distribution diagram of the X-ray response of different detection pixels of the perovskite radiation detection array prepared in Example 2 of the present disclosure under X-ray irradiation;

[0055] Figure 21 This is an imaging diagram of the lead wire-to-plate of the perovskite radiation detection array prepared in Example 2 of the present disclosure;

[0056] Figure 22 This is a spatial resolution curve diagram of the perovskite radiation detection array prepared in Example 2 of the present disclosure. DETAILED DESCRIPTION

[0057] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0058] The endpoints of the ranges and any values ​​disclosed in this disclosure are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in this disclosure.

[0059] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0060] It should be noted that, unless otherwise defined, technical or scientific terms used in this disclosure should have the ordinary meanings understood by persons of ordinary skill in the art to which this disclosure belongs. Where references to "first," "second," or the like are used throughout this disclosure, such references are intended solely to distinguish similar objects and should not be construed as indicating or implying their relative importance, order of precedence, or implicitly specifying the quantity of the technical features being referred to. References to "first," "second," or the like should be understood to be interchangeable where appropriate.

[0061] Figure 1 This is a comparison diagram of the device structure and working principle of the traditional layered semiconductor radiation detector and the Schottky junction-based perovskite radiation detector disclosed in the present invention.

[0062] like Figure 1 As shown in Figure 1, in conventional layered perovskite radiation detectors, photogenerated carriers generated in the radiation absorption layer must migrate across the thickness of the radiation detector device to achieve high detection sensitivity. Consequently, an operating voltage of tens to hundreds of volts is typically required. However, higher operating voltages exacerbate ion migration, reduce device stability, and limit the application of perovskite semiconductor radiation detectors in portable radiation detection devices.

[0063] In the Schottky junction-based perovskite radiation detector proposed in the present disclosure, a porous carbon-perovskite composite material is used as the radiation absorption layer 2. A Schottky junction can be formed at the interface between the carbon material and the perovskite material. The Schottky junction will form a space charge region that blocks electrons and extracts holes. That is, when the perovskite material generates two carriers, photogenerated holes and photogenerated electrons, under the action of the built-in electric field of the Schottky junction, the photogenerated holes can be spontaneously collected by the carbon electrode, and at the same time, the photogenerated electrons are bound in the perovskite material. This makes the device's photogenerated carrier collection no longer dependent on an external voltage, greatly reducing the device's operating voltage. At the same time, the bound photogenerated electrons can play a photoconductive gain role, greatly improving the performance of the radiation detector.

[0064] Figure 2 This is a flow chart for preparing the Schottky junction-based perovskite radiation detector disclosed in the present invention.

[0065] In one aspect of the present disclosure, a method for preparing a Schottky junction-based perovskite radiation detector is proposed, such as Figure 2 As shown, there is no strict order in which steps S1 and S2 are performed. The preparation method includes:

[0066] S1: applying a carbon slurry to a first substrate to form a film, followed by annealing to obtain a carbon electrode layer 1;

[0067] S2: applying a knife coating of the carbon slurry to form a film on a second substrate, soaking the film in an organic solvent for more than 10 minutes, peeling the carbon film from the second substrate, and allowing the film to stand in air until the organic solvent is completely evaporated to obtain a porous carbon film;

[0068] S3: dissolving a metal halide and an organic ammonium salt in a polar organic solvent to obtain a perovskite solution, casting the perovskite solution on a porous carbon film, allowing the perovskite solution to penetrate into the porous carbon film under pressure, and annealing to obtain a radiation absorbing layer 2 composed of a porous carbon-perovskite composite material;

[0069] S4: placing the radiation absorbing layer 2 on the carbon electrode layer 1, and combining the radiation absorbing layer 2 with the carbon electrode layer 1 under pressure;

[0070] S5: coating the perovskite solution on the radiation absorbing layer 2, and obtaining a dense perovskite layer 3 after annealing;

[0071] S6: coating an organic hole injection material on the dense perovskite layer 3 to obtain a hole injection layer 4;

[0072] S7: forming a conductive metal film on the hole injection layer 4 by thermal evaporation to form a top electrode layer 5, thereby obtaining a Schottky junction-based perovskite radiation detector.

[0073] According to embodiments of the present disclosure, a Schottky junction-based perovskite radiation detector and its preparation method are proposed. By preparing a porous carbon-perovskite composite material, a radiation absorption layer with a Schottky junction is constructed. This is not limited by the size of the perovskite single crystal material, allowing the production of a large-area radiation absorption layer with good uniformity and spatial resolution. Furthermore, the present disclosure utilizes a simple preparation method to produce a perovskite radiation detector with stable operating performance and excellent detection and resolution.

[0074] According to an embodiment of the present disclosure, in step S1, the carbon slurry is scraped onto the first substrate to form a film, and the conditions for annealing treatment include: the annealing temperature range includes 100-120°C, for example, it can be selected as 100°C, 110°C, 120°C; the annealing time range includes 10-30 minutes, for example, it can be selected as 10 minutes, 20 minutes, 30 minutes.

[0075] According to the embodiment of the present disclosure, a dense carbon electrode material can be obtained under this annealing condition, which has good ability to transmit carriers and output electrical signals.

[0076] According to an embodiment of the present disclosure, in step S2, the organic solvent may be ethanol, ether, or acetone, and is used to immerse the scraped carbon film to form a porous carbon film material.

[0077] Figure 3 3 is a scanning electron microscope image of the surface morphology of the porous carbon film prepared in the embodiment of the present disclosure.

[0078] Figure 4 3 is a scanning electron microscope image of the cross-sectional morphology of the porous carbon film prepared in the embodiment of the present disclosure.

[0079] According to the embodiment of the present disclosure, Figure 3 、 Figure 4 As shown, the porous carbon film material prepared in the present disclosure has voids and good permeability. The surface of the porous carbon film has uniformly distributed pores with diameters ranging from 200nm to 2μm, which facilitates the injection of perovskite solution. At the same time, the pore size ranging from hundreds of nanometers to micrometers matches the built-in electric field width of the Schottky junction, which is conducive to the extraction of photogenerated holes. The uniform distribution of internal pores and high porosity ensure the uniform distribution of the perovskite material.

[0080] According to an embodiment of the present disclosure, the metal halide includes one or more of lead iodide, tin iodide, copper iodide, manganese iodide, lead bromide, tin bromide, copper bromide, manganese bromide, lead chloride, tin chloride, copper chloride, and manganese chloride;

[0081] The organic ammonium salt includes one or more of methylammonium iodide, formamidine iodide, methylammonium bromide, formamidine bromide, methylammonium chloride, and formamidine chloride;

[0082] The cesium salt includes one or more of cesium iodide, cesium bromide, and cesium chloride;

[0083] The stoichiometric ratio of the organic ammonium salt or cesium salt to the metal halide ranges from 2:1 to 1:1.

[0084] According to the embodiments of the present disclosure, metal halide perovskite material, as a new type of semiconductor material with excellent performance, has elements with higher atomic numbers such as cesium, lead, and iodine, which can effectively absorb high-energy rays such as X-rays, and at the same time has excellent photoelectric properties such as large carrier-lifetime product and high defect tolerance, and is suitable for application in the field of radiation detection.

[0085] According to the embodiment of the present disclosure, during the infiltration of the perovskite solution into the porous carbon film, the pressure conditions include 1.1 to 5 bar, the annealing treatment conditions include: the annealing temperature range includes 80 to 180° C., and the annealing time range includes 2 to 10 hours.

[0086] Figure 5 3 are scanning electron microscope images of the cross-sectional morphology of the porous carbon-perovskite composite material prepared in the embodiments of the present disclosure at different resolutions.

[0087] According to the embodiment of the present disclosure, Figure 5 As shown in the electron microscope image of the present invention, it can be seen that the present invention successfully synthesized a porous carbon-perovskite composite material with dense bonding and smooth morphology, wherein the perovskite material is embedded in the interior of the porous carbon material and tightly bonded, and the perovskite material has coarse grains and good quality.

[0088] According to an embodiment of the present disclosure, during the bonding process between the radiation absorbing layer 2 and the carbon electrode layer 1 , the pressure conditions include a pressure range greater than 0.01 MPa;

[0089] The perovskite solution is coated on the radiation absorbing layer 2 and annealed under the following conditions: the annealing temperature ranges from 50 to 180° C., and the annealing time ranges from 5 to 30 minutes.

[0090] Figure 6 3 is a scanning electron microscope image of the surface morphology of the dense perovskite layer 3 prepared in the embodiment of the present disclosure.

[0091] According to the embodiment of the present disclosure, Figure 6 As shown, a dense perovskite material can be obtained under this annealing condition. It can be seen from the electron microscope image that the dense perovskite layer 3 completely covers the radiation absorption layer 2 without any exposed carbon, so that the dense perovskite layer 3 has good anti-breakdown performance.

[0092] According to an embodiment of the present disclosure, the organic hole injection material includes one of the following: polytriphenylamine, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and polyvinylcarbazole.

[0093] Figure 7 Schematic diagram of the structure of the Schottky junction-based perovskite radiation detector prepared in the present disclosure.

[0094] In another aspect of the present disclosure, a Schottky junction-based perovskite radiation detector prepared by the above method is proposed, such as Figure 7 As shown, including the following stacked settings:

[0095] Carbon electrode layer 1, used for conducting holes to output electrical signals;

[0096] a radiation absorbing layer 2 formed on the carbon electrode layer 1, wherein the radiation absorbing layer 2 is made of a porous carbon-perovskite composite material and has a Schottky junction capable of forming a built-in electric field for generating carriers in response to X-rays;

[0097] A dense perovskite layer 3 is formed on the radiation absorption layer 2 and is used to isolate the radiation absorption layer 2 from the hole injection layer 4 to prevent leakage of the radiation detector;

[0098] a hole injection layer 4 formed on the dense perovskite layer 3 and used to inject holes to maintain electrical neutrality of the internal structure of the perovskite radiation detector and form a circuit; and

[0099] The top electrode layer 5 is formed on the hole injection layer 4 and is used to receive an external bias to guide the carriers generated by the radiation absorbing layer 2 to move toward the carbon electrode layer 1 , thereby assisting in extracting the carriers generated by the radiation absorbing layer 2 .

[0100] According to embodiments of the present disclosure, the radiation detector proposed herein comprises a porous carbon-perovskite composite material with a Schottky junction as the radiation absorption layer. This improves the detector's detection performance while reducing its operating voltage, resulting in the perovskite radiation detector exhibiting excellent performance and stability. This low operating voltage allows the porous structure to be used in portable devices, enabling faster and more accurate portable radiation detection.

[0101] According to the embodiment of the present disclosure, the carriers generated by the radiation absorbing layer 2 include photogenerated holes and photogenerated electrons.

[0102] According to the embodiment of the present disclosure, holes are extracted by the carbon electrode layer 1 under the action of the built-in electric field of the Schottky junction, and photogenerated electrons are bound in the radiation absorption layer 2 due to the obstruction of the Schottky junction.

[0103] According to the disclosed embodiments, the built-in electric field within the Schottky junction allows photogenerated holes to be spontaneously collected by the carbon electrode, while photogenerated electrons are trapped within the perovskite material. This eliminates the need for external voltage to collect photogenerated carriers, significantly reducing the device's operating voltage. Furthermore, the trapped photogenerated electrons can contribute to photoconductive gain, significantly improving the performance of the radiation detector.

[0104] In another aspect of the present disclosure, a perovskite radiation detection array is proposed, comprising a plurality of uniformly distributed radiation detectors as described above.

[0105] According to the embodiments of the present disclosure, a large-area, uniform perovskite radiation detection array has excellent uniformity and spatial resolution.

[0106] It should be noted that the embodiments described are only part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present disclosure, other embodiments obtained by ordinary technicians in this field without making creative work are all within the scope of protection of the present disclosure.

[0107] Example 1

[0108] In Example 1, a Schottky junction-based perovskite radiation detector and a preparation method thereof proposed in the present disclosure were used to prepare a perovskite X-ray detector and a portable radiation alarm. The specific steps are as follows:

[0109] S1: Indium tin oxide (ITO) conductive glass was used as a substrate material and ultrasonically cleaned with detergent, deionized water, acetone, and anhydrous ethanol, respectively. The cleaned ITO substrate was then placed in an oven at 70° C. for drying.

[0110] The conductive carbon paste was evenly coated onto the ITO conductive glass substrate using a doctor blade method, and annealed in air at 150° C. for 20 min to obtain a dense carbon electrode layer 1.

[0111] S2: Use a doctor blade method to evenly apply the conductive carbon paste onto a hydrophobic substrate, and soak it in anhydrous ethanol for 5 hours. After peeling the carbon film from the substrate, let it stand in the air for 5 hours to allow the anhydrous ethanol to evaporate naturally to obtain a porous carbon film.

[0112] S3: Methylamine iodide solution (MAI), lead iodide (PbI2), and methylamine chloride (MACl) are dissolved in 2-methoxyethanol (2-ME) at a molar ratio of 10:10:1 to form a 2.2 M perovskite solution. The perovskite solution is dropped onto the porous carbon film prepared in step S2 to form a composite material. A gas pressure of 1.5 bar is applied to increase the permeability of the perovskite solution. The porous carbon-perovskite composite film is annealed at 120°C and 0.02 MPa for 2 hours to obtain the radiation absorbing layer 2.

[0113] S4: The casting process in step S3 is carried out for a total of 3 cycles. After the third perovskite solution infiltration process is completed, the radiation absorption layer 2 prepared in step S3 is attached to the dense carbon electrode 1 prepared in step S1 and annealed for 2 hours at a temperature of 120°C and a pressure of 0.02 MPa.

[0114] S5: At room temperature, a perovskite solution is spin-coated on the radiation absorbing layer 2 prepared in step S3 to form a dense perovskite layer 3. 50 μL of the perovskite solution is used each time, the spin coater speed is 2000 rpm, and the spin coating is performed for 45 seconds. A nitrogen quench is applied 4 seconds after the start of spin coating, and the dense perovskite film is then annealed at 120°C for 20 minutes. This process is repeated twice.

[0115] S6: Dissolve polytriphenylamine (poly-TPD) as an organic hole injection material in chlorobenzene (CB) to obtain a 6 mg / ml polytriphenylamine solution. Spin-coat the polytriphenylamine solution onto the dense perovskite layer 3 prepared in step S5 at room temperature to form a hole injection layer 4. Each time 30 μL of the polytriphenylamine solution is spin-coated onto the hole transport layer 4, the spin coater speed is 1000 rpm, and each spin coating cycle lasts 30 seconds. The hole injection layer 4 is then annealed at 120°C for 20 minutes.

[0116] S7: On the hole injection layer 4, 8 nm thick molybdenum trioxide (MoO3) and a metal electrode with an area of ​​2 mm×2 mm are sequentially evaporated to form a top electrode layer 5 to obtain a perovskite radiation detector based on a Schottky junction.

[0117] S8: Assemble the Schottky junction-based perovskite radiation detector, current amplification module, alarm determination module, and alarm prepared in step S7 to obtain a portable radiation alarm.

[0118] Example 2

[0119] In Example 2, a portable perovskite radiation detector based on a Schottky junction porous structure and a preparation method thereof disclosed in the present invention were used to prepare a perovskite X-ray detection array. The specific steps are as follows:

[0120] S1: Indium tin oxide (ITO) conductive glass was used as a substrate material and ultrasonically cleaned with detergent, deionized water, acetone, and anhydrous ethanol, respectively. The cleaned ITO substrate was then placed in an oven at 70° C. for drying.

[0121] The conductive carbon paste was evenly coated onto the ITO conductive glass substrate using a doctor blade method, and annealed in air at 150° C. for 20 min to obtain a dense carbon electrode layer 1.

[0122] S2: Use a doctor blade method to evenly apply the conductive carbon paste onto a hydrophobic substrate, and soak it in anhydrous ethanol for 5 hours. After peeling the carbon film from the substrate, let it stand in the air for 5 hours to allow the anhydrous ethanol to evaporate naturally to obtain a porous carbon film.

[0123] S3: Methylamine iodide solution (MAI), lead iodide (PbI2), and methylamine chloride (MACl) are dissolved in 2-methoxyethanol (2-ME) at a molar ratio of 10:10:1 to form a 2.2 M perovskite solution. The perovskite solution is dropped onto the porous carbon film prepared in step S2 to form a composite material. A gas pressure of 1.5 bar is applied to increase the permeability of the perovskite solution. The porous carbon-perovskite composite film is annealed at 120°C and 0.02 MPa for 2 hours to obtain the radiation absorbing layer 2.

[0124] S4: The casting process in step S3 is carried out for a total of 3 cycles. After the third perovskite solution infiltration process is completed, the radiation absorption layer 2 prepared in step S3 is attached to the dense carbon electrode 1 prepared in step S1 and annealed for 2 hours at a temperature of 120°C and a pressure of 0.02 MPa.

[0125] S5: At room temperature, the perovskite solution is coated on the radiation absorbing layer 2 prepared in step S3 using a doctor blade coating method to obtain a dense perovskite layer 3. 50 μL of the perovskite solution is used each time, and the perovskite solution is coated at a speed of 50 mm / s. The gap between the doctor blade and the radiation absorbing layer 2 is 150 μm. After air knife quenching, the dense perovskite layer 3 is annealed at 120° C. for 20 minutes.

[0126] S6: Dissolve polytriphenylamine (poly-TPD) as an organic hole injection material in chlorobenzene (CB) to obtain a 6 mg / ml polytriphenylamine solution. Spin-coat the polytriphenylamine solution onto the dense perovskite layer 3 prepared in step S5 at room temperature to form a hole injection layer 4. Each time 30 μL of the polytriphenylamine solution is spin-coated onto the hole transport layer, the spin coater speed is 1000 rpm, and each spin coating cycle lasts 30 seconds. The hole injection layer 4 is then annealed at 120°C for 20 minutes.

[0127] S7: On the hole injection layer 4, 8 nm thick molybdenum trioxide (MoO3) and metal electrodes with a pixel size of 500 μm×500 μm or 150 μm×150 μm are sequentially evaporated to obtain a perovskite radiation detection array.

[0128] Test Example 1

[0129] The porous carbon-perovskite composite material prepared in the present disclosure was observed under Kelvin probe force microscopy (KPFM) by measuring the contact potential difference (CPD) between the sample surface and the cantilever to observe the charge separation phenomenon under X-ray irradiation.

[0130] Figure 8 This is a diagram of the carrier separation phenomenon observed on the porous carbon-perovskite composite material using a Kelvin probe force microscope in the present disclosure.

[0131] like Figure 8 As shown, Kelvin probe force microscopy can compare the changes in work function of different areas of the film before and after illumination. It was found that the work functions of perovskite materials and carbon materials changed significantly before and after illumination, indicating that carrier separation occurred at the interface between perovskite and carbon.

[0132] Test Example 2

[0133] The detection performance of the Schottky junction-based perovskite radiation detector prepared in the present disclosure was tested.

[0134] Figure 9 2 is a graph showing the sensitivity change of the Schottky junction-based perovskite radiation detector under different bias voltages in the present disclosure.

[0135] Figure 10 This is a graph showing the sensitivity change of a traditional layered perovskite radiation detector under different bias voltages.

[0136] like Figure 9 、 Figure 10As shown, compared with the traditional layered structure perovskite radiation detector, the Schottky junction-based perovskite radiation detector proposed in the present disclosure can achieve more sensitive detection performance under a lower external bias voltage, proving that the performance of the Schottky junction-based perovskite radiation detector proposed in the present disclosure has been significantly improved.

[0137] Among them, the recommended external bias voltage range of the Schottky junction-based perovskite radiation detector proposed in the present disclosure is -0.5 to -1 V. Within this range, the sensitivity of the detector is optimal.

[0138] Figure 11 This is a comparison chart of the signal-to-noise ratio of the Schottky junction-based perovskite radiation detector disclosed in the present invention and the traditional layered structure perovskite radiation detector.

[0139] like Figure 11 As shown, the signal-to-noise ratio of the Schottky junction-based perovskite radiation detector proposed in the present disclosure is significantly higher than that of the traditional layered structure perovskite radiation detector, which proves that the Schottky junction-based perovskite radiation detector proposed in the present disclosure has a stronger ability to receive useful signals.

[0140] Test Example 3

[0141] The device stability of the Schottky junction-based perovskite radiation detector prepared in the present disclosure was tested.

[0142] Perovskite materials are brittle and sensitive to environmental changes, easily oxidized, and intolerant to high temperatures, resulting in short lifespans and poor stability in radiation detectors. In the Schottky junction-based perovskite radiation detector disclosed herein, the radiation absorption layer 2 is made of a porous carbon-perovskite composite material. The perovskite material is embedded within the porous carbon material, forming large, more stable grains. Furthermore, the carbon and perovskite materials form a Schottky junction. At the interface, the perovskite material's energy bands bend, forming a high-potential energy region known as the Schottky barrier. Electrons must possess energies higher than this barrier to cross it and flow into the metal, thereby preventing electrons from the perovskite material from flowing into the carbon material.

[0143] Figure 12 This is a current drift test diagram of the Schottky junction-based perovskite radiation detector in the present disclosure.

[0144] like Figure 12 As shown, when the external bias voltage is -1V, the Schottky junction-based perovskite radiation detector in the present disclosure can maintain long-term current stability, proving that it has good working stability.

[0145] Figure 13 This is a test diagram of the irradiation stability of the Schottky junction-based perovskite radiation detector disclosed in the present invention.

[0146] like Figure 13As shown, the radiation absorption layer 2 in the Schottky junction-based perovskite radiation detector disclosed in the present invention can stably respond to external radiation to output an electrical signal, and its sensitivity can ensure stability over a long period of time.

[0147] Figure 14 This is a test diagram of the working stability of the Schottky junction-based perovskite radiation detector under pulsed X-rays in the present disclosure.

[0148] like Figure 14 As shown, under the action of pulsed X-rays, the Schottky junction-based perovskite radiation detector disclosed in the present invention works stably and has good repeatability.

[0149] Figure 15 This is a long-term stability test diagram of the Schottky junction-based perovskite radiation detector in the present disclosure stored in a nitrogen glove box environment.

[0150] like Figure 15 As shown, in a nitrogen atmosphere, the Schottky junction-based perovskite radiation detector disclosed in the present invention can maintain long-term stability, and its sensitivity is basically maintained at the same level.

[0151] Test Example 4

[0152] The performance of the portable radiation alarm prepared in Example 1 of the present disclosure was tested.

[0153] Figure 16 This is a schematic diagram of the structure of the radiation alarm prepared in Example 1 of the present disclosure.

[0154] like Figure 16 As shown, the radiation alarm is assembled by the Schottky junction-based perovskite radiation detector proposed in the present disclosure, the current amplification module, the alarm determination module, and the alarm.

[0155] Gas discharge counter tubes are a commonly used nuclear radiation detector. A common example is the Geiger-Müller counter (GM tube), an electronic counter that records "pulses" and is commonly used to detect high-energy radiation. They feature large pulse amplitudes, low manufacturing costs, and ease of use. However, they have a narrow operating temperature range, long resolution times, and the potential for spurious counts.

[0156] Figure 17 This is a comparison chart of the response time between the radiation alarm prepared in Example 1 of the present disclosure and the radiation alarm based on the GM counter tube.

[0157] like Figure 17As shown, the radiation alarm device based on the Schottky junction perovskite detector prepared in Example 1 of the present disclosure has a significantly faster response speed than the radiation alarm device based on the GM counter tube, and the response time is increased by 24 times compared with the GM counter tube.

[0158] Figure 18 This is a comparison chart of the energy responses of the radiation alarm prepared in Example 1 of the present disclosure and the radiation alarm based on the GM counter tube to low-energy X-rays.

[0159] like Figure 18 As shown, the radiation alarm device based on the Schottky junction perovskite detector prepared in Example 1 of the present disclosure can respond more accurately to low-energy X-rays. This proves that the radiation alarm device based on the Schottky junction perovskite detector prepared in Example 1 of the present disclosure has better detection performance and response speed than the traditional GM counter tube.

[0160] Test Example 5

[0161] The performance of the perovskite radiation detection array prepared in Example 2 of the present disclosure was tested.

[0162] A perovskite radiation detection array is a device composed of a regular arrangement of multiple radiation-sensitive Schottky-junction perovskite detectors prepared in Example 2 of the present disclosure. The array, in Example 2 of the present disclosure, employs a two-dimensional planar array structure. When imaging a target, because multiple radiation detectors simultaneously receive radiation and output corresponding electrical signals, the array device can increase the radiation dwell time compared to a single radiation detector, improving the system's signal-to-noise ratio and significantly reducing the complexity of the detection system.

[0163] Figure 19 This is a dark current distribution diagram of different detection pixels in a dark environment of the perovskite radiation detection array prepared in Example 2 of the present disclosure.

[0164] Figure 20 This is a photocurrent distribution diagram of the X-ray response of different detection pixels of the perovskite radiation detection array prepared in Example 2 of the present disclosure under X-ray irradiation.

[0165] like Figure 19 、 Figure 20 As shown, the Schottky junction-based perovskite radiation detection array prepared in Example 2 of the present disclosure exhibits good uniformity both in a dark environment and under X-ray irradiation.

[0166] Figure 21 This is an imaging diagram of the lead wire-to-plate by the perovskite radiation detection array prepared in Example 2 of the present disclosure.

[0167] like Figure 21As shown, the left side shows the lead wire-to-board image, and the right side shows the imaging image. Linear scanning imaging of the lead wire-to-board was performed using the Schottky junction-based perovskite radiation detection array prepared in Example 2 of the present disclosure. The imaging effect was extremely clear at resolutions of 2.5 lp / mm, 3.4 lp / mm, 4.6 lp / mm, and 5.5 lp / mm.

[0168] The spatial resolution test was performed on a perovskite radiation detection array with a pixel size of 150 μm×150 μm prepared in Example 2 of the present disclosure. The spatial resolution of a conventional commercial CsI:Tl flat panel detection array is approximately 3 lp / mm.

[0169] Figure 22 This is a spatial resolution curve diagram of the perovskite radiation detection array prepared in Example 2 of the present disclosure.

[0170] like Figure 22 As shown, the spatial resolution of the perovskite radiation detection array prepared in Example 2 of the present disclosure is about 5lp / mm, which proves that its spatial resolution has exceeded that of the commercial CsI:Tl flat-panel detection array and has excellent spatial imaging capabilities.

[0171] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A method for preparing a Schottky junction-based perovskite radiation detector, comprising: The carbon slurry is scraped onto the first substrate to form a film, and then annealed to obtain a carbon electrode layer (1); applying a carbon slurry to a second substrate to form a film by blade coating, soaking the film in an organic solvent for more than 10 minutes, peeling the carbon film from the second substrate, and allowing the film to stand in air until the organic solvent is completely volatilized to obtain a porous carbon film; Dissolving an organic ammonium salt or a cesium salt and a metal halide in a polar organic solvent to obtain a perovskite solution, pouring the perovskite solution onto the porous carbon film, allowing the perovskite solution to penetrate into the porous carbon film under pressure, and annealing to obtain a radiation absorption layer (2) composed of a porous carbon-perovskite composite material, wherein the porous carbon-perovskite composite material forms a Schottky junction with a built-in electric field for generating carriers in response to X-rays; placing the radiation absorbing layer (2) on the carbon electrode layer (1), and combining the radiation absorbing layer (2) with the carbon electrode layer (1) under pressure; The perovskite solution is coated on the radiation absorption layer (2), and after annealing, a dense perovskite layer (3) is obtained; coating an organic hole injection material on the dense perovskite layer (3) to obtain a hole injection layer (4); A conductive metal is formed into a film on the hole injection layer (4) by thermal evaporation to form a top electrode layer (5), thereby obtaining the Schottky junction-based perovskite radiation detector.

2. The method according to claim 1, wherein The carbon slurry is scraped onto the first substrate to form a film, and the annealing treatment conditions include: the annealing temperature range includes 100-120° C., and the annealing time range includes 10-30 minutes.

3. The method according to claim 1, wherein The metal halide includes one or more of lead iodide, tin iodide, copper iodide, manganese iodide, lead bromide, tin bromide, copper bromide, manganese bromide, lead chloride, tin chloride, copper chloride, and manganese chloride; The organic ammonium salt includes one or more of methylammonium iodide, formamidine iodide, methylammonium bromide, formamidine bromide, methylammonium chloride, and formamidine chloride; The cesium salt includes one or more of cesium iodide, cesium bromide, and cesium chloride. The stoichiometric ratio of the organic ammonium salt or cesium salt to the metal halide is 2:1 to 1:

1.

4. The method according to claim 1, wherein During the infiltration of the perovskite solution into the porous carbon film, the pressure condition includes 1.1 to 5 bar, and the annealing treatment conditions include: an annealing temperature range includes 80 to 180° C., and an annealing time range includes 2 to 10 hours.

5. The method according to claim 1, wherein During the bonding process between the radiation absorbing layer (2) and the carbon electrode layer (1), the pressure condition includes a pressure range greater than 0.01 MPa; The perovskite solution is coated on the radiation absorption layer (2), and the conditions for the annealing treatment include: the annealing temperature range includes 50 to 180° C., and the annealing time range includes 5 to 30 minutes.

6. The method according to claim 1, wherein The organic hole injection material includes one of the following: polytriphenylamine, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and polyvinylcarbazole.

7. A Schottky junction-based perovskite radiation detector prepared by the method according to any one of claims 1 to 6, characterized in that: Including the following cascade settings: A carbon electrode layer (1) for conducting holes to output electrical signals; a radiation absorption layer (2) formed on the carbon electrode layer (1), wherein the radiation absorption layer (2) is prepared by a porous carbon-perovskite composite material and has a Schottky junction capable of forming a built-in electric field, and is used for generating carriers in response to X-rays; a dense perovskite layer (3) formed on the radiation absorption layer (2) and used to isolate the radiation absorption layer (2) from the hole injection layer (4) to prevent leakage of the radiation detector; a hole injection layer (4), formed on the dense perovskite layer (3), for injecting holes to maintain electrical neutrality of the internal structure of the perovskite radiation detector and form a loop; and A top electrode layer (5) is formed on the hole injection layer (4) and is used to receive an external bias voltage to guide the carriers generated by the radiation absorption layer (2) to move toward the carbon electrode layer (1), thereby assisting in extracting the carriers generated by the radiation absorption layer (2).

8. The radiation detector according to claim 7, wherein: The carriers generated by the radiation absorption layer (2) include photogenerated holes and photogenerated electrons.

9. The radiation detector according to claim 8, wherein: The holes are extracted by the carbon electrode layer (1) under the action of the built-in electric field of the Schottky junction, and the photogenerated electrons are bound in the radiation absorption layer (2) due to the obstruction of the Schottky junction.

10. A perovskite radiation detection array, comprising a plurality of uniformly distributed radiation detectors according to any one of claims 7 to 9.

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