X-ray detector based on perovskite quantum dot / b-PBD liquid scintillator screen

Abstract

The invention relates to the technical field of biomedical X-ray imaging, in particular to an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, which comprises a substrate and a liquid scintillator screen arranged on the substrate, the liquid scintillator screen comprises a liquid scintillator panel; the liquid scintillator panel is a hollow cylinder, and a perovskite quantum dot / b-PBD solution is packaged in the liquid scintillator panel through epoxy resin glue; the molecular formula of perovskite quantum dots in the perovskite quantum dot / b-PBD solution is CsPbX3, wherein X is one or a mixture of more of Cl, Br or I; the substrate is a CMOS image sensor or a silicon-based photodiode. According to the invention, the perovskite quantum dot / b-PBD liquid scintillator screen and the CMOS image sensor or the silicon-based photodiode are packaged and integrated, the technological process is simple, the height of the scintillator panel can be flexibly modulated, and finally the X-ray detector with high stability is integrated.

Description

Technical Field

[0001] The present application relates to the field of biomedical X-ray imaging technology, and in particular to an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen. Background Art

[0002] X-ray detectors are crucial for medical imaging and are widely used in orthopedics, dentistry, breast surgery, cardiovascular disease, and other fields. However, X-rays exceeding a certain dose can cause harm to the human body. Therefore, the development of low-dose, high-resolution, and highly stable X-ray detectors has become a trend in X-ray imaging technology.

[0003] X-ray detectors can be divided into direct X-ray detectors and indirect X-ray detectors based on their working principles. The working principle of direct X-ray detectors, such as CdZnTe and a-Se, is that the detection material generates electrons and holes under the irradiation of high-energy X-rays. The electrons and holes circulate in the detector to form electrical signals. The working principle of indirect X-ray detectors, such as cesium iodide and gadolinium oxysulfide, is that the detection material converts high-energy X-ray photons into low-energy photons such as ultraviolet light or other visible light. The low-energy photons are received by array photodetectors (for example, amorphous silicon photodiodes, photomultiplier tubes, etc.) and converted into electrical signals.

[0004] Lead halide perovskite quantum dots (molecular formula CsPbX3) are widely used in light-emitting diodes (LEDs), solar cells, lasers, and X-ray detectors due to their unique optical properties such as tunable wavelength, narrow wavelength band, and high quantum efficiency. However, due to the low formation energy of perovskite quantum dots, these materials are easily affected by light, heat, oxygen, and moisture, resulting in a decrease in their luminous efficiency. Perovskite quantum dots can be divided into liquid scintillators and solid scintillators based on their morphology. Perovskite liquid scintillators have three advantages over solid scintillators: (1) Compared with solid scintillators, the quantum dots of liquid scintillators are easy to replace; (2) Scintillators need to be isolated from oxygen and water. Currently, there is a bottleneck in the packaging of solid scintillators, while liquid scintillators themselves are in solvents, which play a certain protective role for the quantum dots; (3) Compared with solid scintillators, liquid scintillators can better resist damage caused by strong radiation and have good area / volume scalability. Summary of the Invention

[0005] The present application provides an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, which integrates the perovskite quantum dot / b-PBD liquid scintillator screen and a CMOS image sensor or a silicon-based photodiode package. The process flow is simple, and the scintillator panel height can be flexibly modulated, ultimately forming a highly stable X-ray detector.

[0006] To solve the above technical problems, in the first aspect, an embodiment of the present application provides an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, comprising: a substrate and a liquid scintillator screen arranged on the substrate; the liquid scintillator screen includes a liquid scintillator panel; the liquid scintillator panel is a hollow cylinder, and the interior of the liquid scintillator panel is encapsulated with a perovskite quantum dot / b-PBD solution by epoxy resin glue; the molecular formula of the perovskite quantum dots in the perovskite quantum dot / b-PBD solution is CsPbX3, wherein X is a mixture of one or more of Cl, Br or I; the substrate is a CMOS image sensor or a silicon-based photodiode.

[0007] In some exemplary embodiments, the height of the cylinder of the liquid scintillator panel is 2 mm to 4 mm; an injection hole with a diameter of 0.8 mm to 1.2 mm is provided on the liquid scintillator panel; and the material of the liquid scintillator panel is a quartz glass container.

[0008] In some exemplary embodiments, the substrate includes a photosensitive element array and an auxiliary circuit connected to each other; wherein the photosensitive element array is used to convert optical signals into electrical signals, and the auxiliary circuit is used to process and output the electrical signals.

[0009] In a second aspect, the embodiment of the present application further provides a method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen as described in the above embodiment, comprising the following steps: step 1, using cesium carbonate, octadecene and oleic acid as raw materials, stirring and heating in an inert gas atmosphere, and obtaining a cesium oleate solution after cooling; step 2, stirring and heating a lead halide solution in an inert gas atmosphere, adding a cesium oleate solution to the lead halide solution, and obtaining perovskite quantum dots after ice bath; step 3, adding methyl acetate to the perovskite quantum dots, and centrifuging to obtain perovskite Quantum dot solution; Step 4, adding b-PBD powder to the perovskite quantum dot solution, mixing evenly to obtain a perovskite quantum dot / b-PBD mixed solution; b-PBD powder is 2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole; Step 5, injecting the perovskite quantum dot / b-PBD solution into the liquid scintillator panel, and sealing it with epoxy resin glue to obtain a perovskite quantum dot / b-PBD liquid scintillator screen; Step 6, encapsulating the obtained perovskite quantum dot / b-PBD liquid scintillator screen and integrating it on the substrate.

[0010] In some exemplary embodiments, in step one, the preparation process of the cesium oleate solution includes: adding cesium carbonate, octadecene and oleic acid to a first reaction container, and sealing the first reaction container with silicone grease after adding a magnet; vacuuming and magnetically stirring at room temperature, and then heating to 120°C while stirring under an inert gas atmosphere; vacuuming at 120°C, and then filling with inert gas, repeating this cycle three times, and continuing to heat to 150°C while stirring under an inert gas atmosphere; maintaining at 150°C for 20 minutes to 30 minutes to allow cesium carbonate and oleic acid to fully react, and finally naturally cooling to room temperature to obtain a cesium oleate solution; the cesium carbonate in the cesium carbonate solution is 0.067M; the inert gas is one of helium, nitrogen and argon.

[0011] In some exemplary embodiments, in step 2, the preparation process of perovskite quantum dots includes: adding a lead halide solution to a second reaction container, adding magnetic particles, sealing the second reaction container with silicone grease, and then placing it in a heating device for heating; vacuuming and magnetically stirring at room temperature, and then heating to 120°C while stirring under an inert gas atmosphere; vacuuming at 120°C, then filling with inert gas, repeating this cycle three times, and heating to 150°C while stirring under an inert gas atmosphere; then quickly injecting a 150°C cesium oleate solution, reacting for 5 seconds, and then quickly removing the second reaction container and placing it in ice water for an ice bath to obtain perovskite quantum dots; the lead halide solution includes lead halide, octadecene, oleic acid and oleylamine; the lead halide is one or more of lead iodide, lead bromide, and lead chloride.

[0012] In some exemplary embodiments, in step 2, the lead halide solution is 0.032 M; the cesium oleate in the rapidly injected cesium oleate solution is 0.027 mmol; the inert gas is one of helium, nitrogen, and argon; when the perovskite quantum dots are CsPbCl3 quantum dots, a trioctylphosphine solvent with a concentration of 97% is added to dissolve lead chloride, and the lead chloride in the lead chloride solution is 0.028 M.

[0013] In some exemplary embodiments, in step three, methyl acetate is added to the perovskite quantum dots and centrifuged, the supernatant is discarded after centrifugation, leaving a precipitate, and the precipitate is dissolved in an anhydrous dry-grade chlorobenzene solution to prepare a perovskite quantum dot solution; wherein the volume of chlorobenzene is equal to the ratio of the mass of the perovskite quantum dots to the concentration of the quantum dot solution.

[0014] In some exemplary embodiments, in step three, when the perovskite quantum dots are CsPbCl 3 quantum dots, 1 mL of trioctylphosphine solvent is added to dissolve lead chloride.

[0015] In some exemplary embodiments, in step 4, the concentration of b-PBD is 1 g / l to 200 g / l.

[0016] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0017] An embodiment of the present application provides an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, comprising: a substrate and a liquid scintillator screen arranged on the substrate; the liquid scintillator screen includes a liquid scintillator panel; the liquid scintillator panel is a hollow cylinder, and a perovskite quantum dot / b-PBD solution is encapsulated inside the liquid scintillator panel by epoxy resin glue; the molecular formula of the perovskite quantum dots in the perovskite quantum dot / b-PBD solution is CsPbX3, wherein X is a mixture of one or more of Cl, Br or I; the substrate is a CMOS image sensor or a silicon-based photodiode.

[0018] The present application provides an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, wherein the liquid scintillator screen includes a scintillator panel, a perovskite quantum dot / b-PBD solution, and an epoxy resin glue. b-PBD can significantly enhance the luminescence intensity of quantum dots under X-rays. Epoxy resin glue has good bonding strength and chemical resistance, and the curing condition is room temperature curing. After curing, it not only has good light transmittance, but also can well isolate water and oxygen. Therefore, sealing the injection hole with epoxy resin can improve the stability of the quantum dots. The perovskite quantum dot / b-PBD liquid scintillator screen and the CMOS image sensor or silicon-based photodiode package are integrated, the process flow is simple, and the height of the scintillator panel can be flexibly modulated, and finally a highly stable X-ray detector is assembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily described by the pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0020] Figure 1 and Figure 2 It is a schematic structural diagram of the X-ray detector of the perovskite quantum dot / b-PBD liquid scintillator screen according to an embodiment of the present application.

[0021] Figure 3 is an image of a liquid scintillator panel according to an embodiment of the present application.

[0022] Figure 4 This is the perovskite quantum dot / b-PBD liquid scintillator screen of the embodiment of the present application under the irradiation of fluorescent lamp and ultraviolet lamp.

[0023] Figure 5 This is a PL spectrum diagram of the environmental stability of the perovskite quantum dot / b-PBD liquid scintillator screen in an embodiment of the present application.

[0024] Figure 6 This is a comparison chart of RL of the perovskite quantum dots with and without b-PBD added in the embodiment of the present application. DETAILED DESCRIPTION

[0025] As known from the background art, since perovskite quantum dots have low formation energy, these materials are easily affected by light, heat, oxygen and moisture, resulting in a decrease in their luminous efficiency.

[0026] In order to solve the above technical problems, the embodiment of the present application provides an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, comprising: a substrate and a liquid scintillator screen arranged on the substrate; the liquid scintillator screen includes a liquid scintillator panel; the liquid scintillator panel is a hollow cylinder, and the interior of the liquid scintillator panel is encapsulated with a perovskite quantum dot / b-PBD solution by epoxy resin glue; the molecular formula of the perovskite quantum dots in the perovskite quantum dot / b-PBD solution is CsPbX3, wherein X is a mixture of one or more of Cl, Br or I; the substrate is a CMOS image sensor or a silicon-based photodiode. The present application integrates the perovskite quantum dot / b-PBD liquid scintillator screen and the CMOS image sensor or silicon-based photodiode package, with a simple process flow and flexible modulation of the scintillator panel height, ultimately forming a highly stable X-ray detector.

[0027] The following detailed description of the various embodiments of the present application is provided in conjunction with the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present application to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0028] See Figure 1 The embodiment of the present application provides an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, comprising: a substrate 3 and a liquid scintillator screen 2 arranged on the substrate 3; Figure 2 As shown, the liquid scintillator screen 2 includes a liquid scintillator panel 4; the liquid scintillator panel 4 is a hollow cylinder, and the inside of the liquid scintillator panel 4 is encapsulated with a perovskite quantum dot / b-PBD solution by an epoxy resin glue 5; the molecular formula of the perovskite quantum dots in the perovskite quantum dot / b-PBD solution is CsPbX3, wherein X is a mixture of one or more of Cl, Br or I; the substrate 3 is a CMOS image sensor or a silicon-based photodiode.

[0029] Specifically, the substrate 3 is a CMOS / TFT / PD image sensor. Figure 1In the figure, the medical X-ray 1 is generated by an X-ray tube, the photon energy is in the range of 15keV to 150keV, and the corresponding wavelength is in the range of 0.008nm to 0.08nm. The liquid in the liquid scintillator screen 2 is a mixed solution of perovskite quantum dots and b-PBD.

[0030] In some embodiments, the cylinder of the liquid scintillator panel 4 has a height of 2 mm to 4 mm; an injection hole with a diameter of 0.8 mm to 1.2 mm is provided on the liquid scintillator panel 4; and the liquid scintillator panel 4 is made of a quartz glass container. The height of the liquid scintillator panel 4 is adjustable. The height of the liquid scintillator screen 3 can be flexibly adjusted to maximize imaging sensitivity.

[0031] Specifically, the liquid scintillator panel 4 may be an integrally formed quartz glass container with a height ranging from 2 mm to 4 mm and an injection hole with a diameter of 0.8 mm to 1.2 mm. Figure 3 The figure shows an integrally formed liquid scintillator panel 4 with injection holes without any quantum dots loaded therein.

[0032] Figure 4 The following images show a perovskite quantum dot / b-PBD liquid scintillator screen under fluorescent light and ultraviolet light. (a) shows the perovskite quantum dot / b-PBD liquid scintillator screen under ultraviolet light, and (b) shows the perovskite quantum dot / b-PBD liquid scintillator screen under fluorescent light.

[0033] Figure 5 The PL spectrum of the environmental stability of the perovskite quantum dot / b-PBD liquid scintillator screen according to the embodiment of the present application is shown; it mainly characterizes the stability of the perovskite quantum dot / b-PBD liquid scintillator screen in the environment. Figure 5 Figure (a) in the middle refers to the PL spectrum of the perovskite quantum dot / b-PBD liquid scintillator screen in the environment at regular intervals (e.g., 1 day, 3 days, 14 days, etc.) (the PL spectrum excitation light source is a 365 nm ultraviolet lamp). Figure 5 (a) The figure reflects the change of PL intensity of perovskite quantum dots / b-PBD liquid scintillator screen in the environment from 0 to 104 days. Figure 5 The black line in (b) refers to the change in the ratio (Remnantintensity) of the PL peak intensity of the perovskite quantum dot / b-PBD liquid scintillator screen from 0 to 104 days in the environment to the original (0 day) PL peak intensity. Figure 5 The red line in (b) refers to the change of the PL half-peak width (FWHM) of the perovskite quantum dot / b-PBD liquid scintillator screen in the environment from 0 to 104 days. Figure 5It shows that after the perovskite quantum dot / b-PBD liquid scintillator screen was placed in the environment for 104 days, its PL intensity dropped to 82.7% of the initial intensity; during the period of 0 to 104 days, the half-peak width (FWHM) of the PL fluctuated around 26.5nm, and the peak position fluctuated around 520nm. Figure 5 This shows that the luminous intensity of the perovskite quantum dot / b-PBD liquid scintillator screen has basically not decreased after being placed in the environment for 104 days, and the half-peak width and peak position have basically not changed. Figure 5 This shows that the perovskite quantum dot / b-PBD liquid scintillator screen has high environmental stability.

[0034] Figure 6 A comparison diagram of RL of perovskite quantum dots with and without b-PBD added is shown in an embodiment of the present application. Figure 6 It shows that b-PBD (2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole) can enhance the luminescence intensity of CsPbBr3 quantum dots under X-rays. Figure 6 The dark green line refers to the RL intensity of CsPbBr3 (60 mg / ml), the light green line refers to the RL intensity of the mixed solution of CsPbBr3 (60 mg / ml) + b-PBD (20 mg / ml), and the blue line refers to the RL intensity of b-PBD (20 mg / ml). Figure 6 It can be seen that b-PBD can significantly enhance the luminescence intensity of CsPbBr3 quantum dots under X-rays.

[0035] In some embodiments, the substrate 3 includes a connected photosensitive element array and an auxiliary circuit; that is, the CMOS image sensor or the silicon-based photodiode includes a connected photosensitive element array and an auxiliary circuit; wherein the photosensitive element array is used to convert the optical signal into an electrical signal, and the auxiliary circuit is used to process and output the electrical signal.

[0036] In addition, an embodiment of the present application further provides a method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen as described in the above embodiment, comprising the following steps:

[0037] Step 1: Using cesium carbonate, octadecene and oleic acid as raw materials, stirring and heating under an inert gas atmosphere, and cooling to obtain a cesium oleate solution.

[0038] Step 2: Stir and heat the lead halide solution under an inert gas atmosphere, add cesium oleate solution to the lead halide solution, and then ice-bathe to obtain perovskite quantum dots.

[0039] Step 3: Add methyl acetate to the perovskite quantum dots and centrifuge to obtain a perovskite quantum dot solution.

[0040] Step 4: Add b-PBD powder to the perovskite quantum dot solution and mix evenly to obtain a perovskite quantum dot / b-PBD mixed solution; the b-PBD powder is 2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole.

[0041] Step 5: inject the perovskite quantum dot / b-PBD solution into the liquid scintillator panel and seal it with epoxy resin glue to obtain the perovskite quantum dot / b-PBD liquid scintillator screen.

[0042] Step 6: Encapsulate and integrate the prepared perovskite quantum dot / b-PBD liquid scintillator screen on a substrate.

[0043] In some embodiments, in step 1, the preparation process of the cesium oleate solution includes: adding cesium carbonate, octadecene and oleic acid to a first reaction container, and sealing the first reaction container with silicone grease after adding a magnet; vacuuming and magnetically stirring at room temperature, and then heating to 120°C while stirring in an inert gas atmosphere; vacuuming at 120°C, and then filling with inert gas, repeating this cycle three times, and continuing to heat to 150°C while stirring in an inert gas atmosphere; maintaining at 150°C for 20 minutes to 30 minutes to allow cesium carbonate and oleic acid to fully react, and finally naturally cooling to room temperature to obtain a cesium oleate solution; the cesium carbonate in the cesium carbonate solution is 0.067M; the inert gas is one of helium, nitrogen and argon.

[0044] Preferably, in step 1, vacuuming and magnetic stirring are performed at room temperature for 10 minutes, and then heating to 120° C. while stirring under an inert gas atmosphere; vacuuming at 120° C. for 5 minutes, followed by filling with inert gas for 5 minutes, and repeating this cycle three times, and then heating to 150° C. while stirring under an inert gas atmosphere; maintaining at 150° C. for 30 minutes, and finally naturally cooling to room temperature to obtain a cesium oleate solution.

[0045] In some embodiments, in step 2, the preparation process of perovskite quantum dots (molecular formula is CsPbX3, wherein X=Cl, Br, I or one or more mixtures) includes: adding a lead halide solution (lead halide, octadecene, oleic acid and oleylamine) to a second reaction container in a certain proportion, sealing the second reaction container with silicone grease after adding a magnet, and then placing it in a heating device for heating; vacuuming and magnetic stirring at room temperature, and then heating to 120°C while stirring under an inert gas atmosphere; vacuuming at 120°C, then filling with inert gas, repeating this cycle 3 times, and heating to 150°C while stirring under an inert gas atmosphere; then quickly injecting a cesium oleate solution at 150°C, reacting for 5 seconds, and then quickly removing the second reaction container and placing it in ice water for an ice bath to obtain perovskite quantum dots; the lead halide solution includes lead halide, octadecene, oleic acid and oleylamine; the lead halide is one or more of lead iodide, lead bromide and lead chloride.

[0046] Preferably, in step 2, the mixture is vacuumed and magnetically stirred at room temperature for 10 minutes, and then heated to 120°C while stirring under an inert gas atmosphere. Vacuumed at 120°C for 5 minutes, then filled with inert gas for 5 minutes, and repeated three times, and then heated to 150°C while stirring under an inert gas atmosphere. Then, a certain amount of 150°C cesium oleate solution (prepared as described in step 1) is quickly injected. After reacting for 5 seconds, the second reaction vessel is quickly removed and placed in ice water for an ice bath to obtain perovskite quantum dots. For the preparation of CsPbCl3 quantum dots, other solvents need to be added to dissolve them.

[0047] In some embodiments, in step 2, the lead halide solution is 0.032M; the cesium oleate in the rapidly injected cesium oleate solution is 0.027mmol; the inert gas is one of helium, nitrogen and argon; when the perovskite quantum dots are CsPbCl3 quantum dots, a trioctylphosphine solvent with a concentration of 97% is added to dissolve lead chloride, and the lead chloride in the lead chloride (PbCl2) solution is 0.028M.

[0048] In some embodiments, in step three, methyl acetate twice the volume of the solution is added to the perovskite quantum dots and centrifuged. After centrifugation, the supernatant is poured off to leave a precipitate, and the precipitate is dissolved in an anhydrous dry-grade chlorobenzene solution to prepare a perovskite quantum dot solution; wherein the volume of chlorobenzene is equal to the ratio of the mass of the perovskite quantum dots to the concentration of the quantum dot solution.

[0049] In some embodiments, in step 3, when the perovskite quantum dots are CsPbCl 3 quantum dots, 1 mL of trioctylphosphine solvent is added to dissolve lead chloride.

[0050] In some embodiments, in step 4, the concentration of b-PBD is 1 g / l to 200 g / l.

[0051] In step five, the perovskite quantum dot / b-PBD solution is injected into a liquid scintillator panel, and the injection hole is sealed with epoxy resin to produce a perovskite quantum dot / b-PBD liquid scintillator screen. Then, in step six, the perovskite quantum dot / b-PBD liquid scintillator screen is packaged and integrated onto a CMOS image sensor or silicon-based photodiode.

[0052] In this embodiment, when synthesizing the precursor cesium oleate in the process of preparing perovskite quantum dots, the mass of cesium carbonate in the mixed reaction solution is 239 mg, the volume of octadecene is 10 ml, and the volume of oleic acid is 1 ml.

[0053] In this embodiment, the protective inert gas used when synthesizing the precursor cesium oleate during the preparation of perovskite quantum dots can be one of helium, nitrogen, and argon.

[0054] In this embodiment, during the preparation of the perovskite quantum dot / b-PBD liquid scintillator screen, the perovskite quantum dots are CsPbX3, wherein X=Cl, Br, I or a mixture thereof.

[0055] In this embodiment, in the process of preparing perovskite quantum dots, the mass of lead bromide in the mixed solution before hot injection is 69 mg, the volume of octadecene is 5 ml, the volume of oleylamine is 0.4 ml, and the volume of oleic acid is 0.4 ml; the volume of the injected cesium oleate solution is 0.4 mL.

[0056] In this embodiment, during the preparation of perovskite quantum dots / b-PBD, the concentration of CsPbBr3 quantum dots is 30 mg / ml and 60 mg / ml.

[0057] In this embodiment, during the preparation of perovskite quantum dots / b-PBD, b-PBD is used to enhance the luminescence intensity of perovskite quantum dots under X-rays, and the concentration of b-PBD in the mixed solution is 20 mg / ml and 60 mg / ml.

[0058] In this embodiment, the diameter of the liquid scintillator panel is 50 mm, the height is 2 mm, and the injection hole diameter is 1.2 mm.

[0059] In this embodiment, the glue used to encapsulate the injection hole is epoxy resin glue.

[0060] In this embodiment, the CMOS or silicon-based photodiode includes a photosensitive element array and an auxiliary circuit. The photosensitive element array can convert optical signals into electrical signals, and the auxiliary circuit processes and outputs the electrical signals.

[0061] The X-ray detector of the perovskite quantum dot / b-PBD liquid scintillator screen provided in the above embodiments achieves the characteristics of high sensitivity and high stability.

[0062] Based on the above technical solution, an embodiment of the present application provides an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, comprising: a substrate 3 and a liquid scintillator screen 2 arranged on the substrate 3; the liquid scintillator screen 2 includes a liquid scintillator panel 4; the liquid scintillator panel 4 is a hollow cylinder, and the inside of the liquid scintillator panel 4 is encapsulated with a perovskite quantum dot / b-PBD solution by epoxy resin glue 5; the molecular formula of the perovskite quantum dots in the perovskite quantum dot / b-PBD solution is CsPbX3, wherein X is a mixture of one or more of Cl, Br or I; the substrate is a CMOS image sensor or a silicon-based photodiode.

[0063] The present application provides an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen, wherein the liquid scintillator screen includes a scintillator panel, a perovskite quantum dot / b-PBD solution, and an epoxy resin glue. b-PBD can significantly enhance the luminescence intensity of quantum dots under X-rays. Epoxy resin glue has good bonding strength and chemical resistance, and the curing condition is room temperature curing. After curing, it not only has good light transmittance, but also can well isolate water and oxygen. Therefore, sealing the injection hole with epoxy resin can improve the stability of the quantum dots. The perovskite quantum dot / b-PBD liquid scintillator screen and the CMOS image sensor or silicon-based photodiode package are integrated, the process flow is simple, and the height of the scintillator panel can be flexibly modulated, and finally a highly stable X-ray detector is assembled.

[0064] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. An X-ray detector based on perovskite quantum dots / b-PBD liquid scintillator screen, characterized in that: include: A substrate and a liquid scintillator screen disposed on the substrate; The liquid scintillator screen comprises a liquid scintillator panel; The liquid scintillator panel is a hollow cylinder, and the inside of the liquid scintillator panel is encapsulated with a perovskite quantum dot / b-PBD solution by epoxy resin glue; The molecular formula of the perovskite quantum dots in the perovskite quantum dots / b-PBD solution is CsPbX3, wherein X is a mixture of one or more of Cl, Br or I; The substrate is a CMOS image sensor or a silicon-based photodiode.

2. The X-ray detector based on perovskite quantum dots / b-PBD liquid scintillator screen according to claim 1, characterized in that: The height of the cylinder of the liquid scintillator panel is 2 mm to 4 mm; The liquid scintillator panel is provided with an injection hole with a diameter of 0.8 mm to 1.2 mm; The material of the liquid scintillator panel is a quartz glass container.

3. The X-ray detector based on perovskite quantum dots / b-PBD liquid scintillator screen according to claim 1, characterized in that: The substrate includes a photosensitive element array and an auxiliary circuit connected to each other; wherein the photosensitive element array is used to convert optical signals into electrical signals, and the auxiliary circuit is used to process and output the electrical signals.

4. A method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: using cesium carbonate, octadecene and oleic acid as raw materials, stirring and heating under an inert gas atmosphere, and cooling to obtain a cesium oleate solution; Step 2: Stirring and heating the lead halide solution under an inert gas atmosphere, adding cesium oleate solution to the lead halide solution, and obtaining perovskite quantum dots after ice bathing; Step 3, adding methyl acetate to the perovskite quantum dots and centrifuging to obtain a perovskite quantum dot solution; Step 4: Add b-PBD powder to the perovskite quantum dot solution, mix well to obtain a perovskite quantum dot / b-PBD mixed solution; the b-PBD powder is 2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole; Step 5: injecting the perovskite quantum dot / b-PBD solution into the liquid scintillator panel and sealing it with epoxy resin glue to obtain the perovskite quantum dot / b-PBD liquid scintillator screen; Step six: Encapsulate and integrate the prepared perovskite quantum dot / b-PBD liquid scintillator screen on a substrate.

5. The method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen according to claim 4, characterized in that: In the step 1, the preparation process of the cesium oleate solution includes: Cesium carbonate, octadecene and oleic acid are added to a first reaction container, and after adding a magnet, the first reaction container is sealed with silicone grease; vacuuming and magnetic stirring are performed at room temperature, and then heating to 120° C. while stirring in an inert gas atmosphere; vacuuming at 120° C., and then filling with inert gas, repeating this cycle three times, and continuing to heat to 150° C. while stirring in an inert gas atmosphere; maintaining at 150° C. for 20 min to 30 min to allow cesium carbonate and oleic acid to fully react, and finally naturally cooling to room temperature to obtain a cesium oleate solution; The cesium carbonate in the cesium carbonate solution is 0.067M; The inert gas is one of helium, nitrogen and argon.

6. The method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen according to claim 4, characterized in that: In the step 2, the preparation process of perovskite quantum dots includes: The lead halide solution is added to the second reaction container, and after adding the magnet, the second reaction container is sealed with silicone grease, and then placed in a heating device for heating; vacuuming and magnetic stirring are performed at room temperature, and then heating to 120° C. while stirring in an inert gas atmosphere; vacuuming at 120° C., and then filling with inert gas, repeating this cycle for 3 times, and then heating to 150° C. while stirring in an inert gas atmosphere; then quickly injecting cesium oleate solution at 150° C., reacting for 5 seconds, and then quickly removing the second reaction container and placing it in ice water for ice bathing to obtain perovskite quantum dots; The lead halide solution comprises lead halide, octadecene, oleic acid and oleylamine; The lead halide is one or more of lead iodide, lead bromide and lead chloride.

7. The method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen according to claim 5, characterized in that: In the step 2, the lead halide solution is 0.032M; the cesium oleate in the rapidly injected cesium oleate solution is 0.027mmol; the inert gas is one of helium, nitrogen and argon; When the perovskite quantum dots are CsPbCl3 quantum dots, a trioctylphosphine solvent with a concentration of 97% is added to dissolve the lead chloride, and the lead chloride in the lead chloride solution is 0.028M.

8. The method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen according to claim 4, characterized in that: In the step 3, methyl acetate is added to the perovskite quantum dots and centrifuged, the supernatant is discarded after centrifugation, and the precipitate is left, and the precipitate is dissolved in an anhydrous dry grade chlorobenzene solution to prepare a perovskite quantum dot solution; The volume of chlorobenzene is equal to the ratio of the mass of perovskite quantum dots to the concentration of the quantum dot solution.

9. The method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen according to claim 4, characterized in that: In the step 3, when the perovskite quantum dots are CsPbCl3 quantum dots, 1 mL of trioctylphosphine solvent is added to dissolve lead chloride.

10. The method for preparing an X-ray detector based on a perovskite quantum dot / b-PBD liquid scintillator screen according to claim 4, characterized in that: In the step 4, the concentration of b-PBD is 1 g / l to 200 g / l.

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