Preparation method of cesium copper iodide nanocrystal-embedded polymer composite material

Abstract

The present invention relates to a preparation method of cesium copper iodide nanocrystal-embedded polymer composite materials, which comprises the following steps: S1: After mixing cuprous iodide, zinc iodide, oleic acid, oleylamine and octadecene, the temperature is raised until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution; S2: In the copper iodide precursor solution obtained in S1, a preheated cesium oleate precursor solution is added, and after the reaction is completed, a Cs3Cu2I5 nanocrystal solution is obtained through post-treatment; S3: In the Cs3Cu2I5 nanocrystal solution obtained in S2, an EVA organic solution is added and mixed to obtain a cesium copper iodide nanocrystal-embedded polymer composite material. The present invention achieves the purpose of obtaining high-quality Cs3Cu2I5 NCs with uniform size and morphology, and realizes the application of nanocrystal-embedded polymer composite materials in X-ray scintillators.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic materials, and in particular to a preparation method of cesium copper iodide nanocrystal-embedded polymer composite materials. Background Art

[0002] Zero-dimensional lead-free cesium copper iodide nanocrystals (Cs 3 Cu 2 I 5 NCs) have broad application prospects in optoelectronic fields such as light-emitting diodes, ultraviolet photodetectors, X-ray imaging, and anti-counterfeiting technology due to their high emission stability, low self-absorption, relatively low toxicity, and earth-abundant components.

[0003] Currently, the preparation of Cs 3 Cu 2 I 5 NCs materials has made great progress, but there are still the following problems: 1) The insufficient synthesis reaction of Cs 3 Cu 2 I 5 NCs and the difficulty in controlling the crystal size, morphology, and uniformity are still the main obstacles to device performance. Especially for Cs 3 Cu 2 I 5 bulk crystals synthesized by solid-state methods have limitations in controlling their uniformity and morphology; 2) Cs 3 Cu 2 I 5 NCs have poor air stability. Usually, moisture / oxygen can cause the decomposition / oxidation of Cs 3 Cu 2 I 5 NCs, and even phase transformation occurs to convert into CsCu 2 I 3 with low fluorescence quantum yield. Therefore, it is necessary to develop Cs 3 Cu 2 I 5 NCs with uniform size, morphology, and high stability to achieve better optoelectronic applications. Summary of the Invention

[0004] The problem to be solved by the present invention is to provide a preparation method of cesium copper iodide nanocrystal-embedded polymer composite materials for the above-mentioned deficiencies in the prior art, which achieves the purpose of obtaining high-quality Cs 3 Cu 2 I 5 NCs with uniform size and morphology, and realizes the application of nanocrystal-embedded polymer composite materials in X-ray scintillators.

[0005] The above object of the present invention is achieved by the following technical solutions:

[0006] A preparation method of cesium copper iodide nanocrystal-embedded polymer composite material, comprising the following steps,

[0007] S1: After mixing cuprous iodide, zinc iodide, oleic acid, oleylamine and octadecene, the temperature is raised until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution;

[0008] S2: In the copper iodide precursor solution obtained in S1, a preheated cesium oleate precursor solution is added, and after the reaction ends, through post-treatment, a Cs 3 Cu 2 I 5 nanocrystal solution is obtained;

[0009] S3: In the Cs 3 Cu 2 I 5 nanocrystal solution obtained in S2, an EVA organic solution is added and mixed to obtain a cesium copper iodide nanocrystal-embedded polymer composite material.

[0010] Further, in S1, the mass-volume ratio of cuprous iodide, zinc iodide, oleic acid, oleylamine and octadecene is (0.10~0.20) g: (0~2.55) g: (0.60~1.00) mL: (0.80~1.20) mL: (10~20) mL.

[0011] Further, in S1, cuprous iodide, zinc iodide, oleic acid, oleylamine and octadecene are added to a reaction vessel and mixed. After exhausting the air, the temperature is first raised to 100~130 °C. After the temperature is stabilized, the temperature is further raised to 150~180 °C until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution.

[0012] Further, in S2, the cesium oleate precursor solution is prepared from raw materials including cesium carbonate, oleic acid and octadecene.

[0013] Still further, in S2, the preparation process of the cesium oleate precursor solution includes: after mixing cesium carbonate, oleic acid and octadecene, the temperature is first raised to 100~140 °C under a nitrogen atmosphere and stirred for 20~40 min, and then the temperature is further raised to 130~170 °C and stirred to obtain a cesium oleate precursor solution.

[0014] Still further, in S2, the mass-volume ratio of cesium carbonate, oleic acid and octadecene is (0.60~0.80) g: (2.50~3.50) mL: (5~10) mL.

[0015] Further, in the step S2, into the copper iodide precursor solution obtained in the step S1, a cesium oleate precursor solution preheated to 100-140 °C is added. After reacting for 20-40 s, it is stirred and cooled to 10-30 °C. The precipitate is collected by centrifugation and dispersed in an organic solvent, and then the supernatant is collected by centrifugation to obtain a Cs 3 Cu 2 I 5 nanocrystal solution.

[0016] Furthermore, in the step S2, the centrifugation speed is controlled to be 6000-10000 rpm / min and the time is 3-6 min, and the organic solvent is toluene, octane or cyclohexane.

[0017] Further, in the step S3, the organic solvent is toluene, octane or cyclohexane, and the mass-volume ratio of EVA to the organic solvent is (1.8-2.2) g:(5-15) mL. The volume ratio of the EVA organic solution to the Cs 3 Cu 2 I 5 nanocrystal solution is (0.8-1.2):(1.0-5.0).

[0018] Further, in the step S3, first EVA is dissolved in the organic solvent to obtain a colloidal EVA organic solution, and then it is dispersed in the Cs 3 Cu 2 I 5 nanocrystal solution obtained in the step S2 and mixed to obtain a cesium copper iodide nanocrystal-embedded polymer composite material. When in use, the cesium copper iodide nanocrystal-embedded polymer composite material is transferred to a petri dish and slowly evaporated at room temperature in a fume hood to prepare a nanocrystal-embedded polymer composite film for X-ray scintillator imaging.

[0019] In summary, the beneficial technical effects of the present invention are as follows:

[0020] 1. The Cs 3 Cu 2 I 5 nanocrystals prepared by the present invention have the characteristics of high emission stability, low toxicity, economic environmental protection, and rich earth element composition compared with traditional scintillator crystals. By doping zinc into the nanocrystals, the grain size can be reduced and the fluorescence quantum yield (PLQY) can be improved at the same time;

[0021] 2. The process of the nanocrystal-embedded polymer composite material prepared by the present invention is simple, the cost is low, it is non-toxic and harmless, the preparation period is short, the composite film prepared therefrom has a smooth surface, uniform texture, good flexibility effect, easy control of thickness and size, has a certain hydrophobicity (contact angle > 100°), and has a high PLQY (> 65%), and the fluorescence decay lifetime is 3.7 μs, which is suitable for applications in the direction of X-ray detection;

[0022] 3. The nanocrystal-embedded polymer composite material prepared by the present invention has a good response to the X-ray tube voltage, and shows a good linearity in the response to the X-ray dose rate. Under the irradiation of X-rays at 50 keV, the composite film can distinguish a test area with a spatial resolution as high as 15.7 lp mm -1 and has a low detection limit (0.31 μGy air s -1 ), which is about 18 times lower than the standard medical examination dose (5.5 μGy air s -1 ). Description of the Drawings

[0023] Figure 1 is the preparation flow chart of cesium copper iodide nanocrystals in Example 1 of the present invention.

[0024] Figure 2 is the preparation flow chart of the nanocrystal-embedded polymer composite material in Example 1 of the present invention.

[0025] Figure 3 are the TEM image and particle size distribution diagram of cesium copper iodide nanocrystals in Example 2.

[0026] Figure 4 are the TEM image and particle size distribution diagram of cesium copper iodide nanocrystals in Example 3.

[0027] Figure 5 is the optical picture of the nanocrystal-embedded polymer composite film in Example 3. The left and right pictures are the photos of the composite film under natural light and 254 nm ultraviolet light respectively.

[0028] Figure 6 is the water contact angle test diagram of the nanocrystal-embedded polymer composite material in Example 3

[0029] Figure 7 is the X-ray imaging test diagram of the nanocrystal-embedded polymer composite material in Example 3. The left and right pictures are the imaging photos of a ballpoint pen and a fish respectively.

[0030] Figure 8 is the MTF calculation diagram of the film and the scintillator film on the X-ray imaging standard resolution card of the nanocrystal-embedded polymer composite material in Example 3.

[0031] Figure 9 is the function diagram of the radioluminescence intensity of the nanocrystal-embedded polymer composite material in Example 3 as a function of the dose rate and its detection limit. Detailed Embodiments

[0032] To make the technical means, creative features, achieved purposes and functions of the present invention clearer and easier to understand, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Example

[0033] Example 1: A preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material disclosed in the present invention includes the following steps.

[0034] S1: After mixing cuprous iodide, zinc iodide, oleic acid, oleylamine and octadecene, the temperature is raised until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution.

[0035] S2: In the copper iodide precursor solution obtained in S1, a preheated cesium oleate precursor solution is added. After the reaction ends, through post-treatment, a Cs 3 Cu 2 I 5 nanocrystal solution is obtained.

[0036] S3: In the Cs 3 Cu 2 I 5 nanocrystal solution obtained in S2, an EVA organic solution is added and mixed to obtain a cesium copper iodide nanocrystal-embedded polymer composite material.

[0037] Example 2: A preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material disclosed in the present invention is different from that of Example 1 in that

[0038] S1: Add 0.15 g of cuprous iodide, 0 g of zinc iodide, 0.80 mL of oleic acid, 1.00 mL of oleylamine and 15 mL of octadecene into a reaction vessel and mix them. After evacuating to vacuum, first raise the temperature to 120 °C. After the temperature is stable, then raise the temperature to 170 °C until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution.

[0039] S2: Mix 0.72 g of cesium carbonate, 3.00 mL of oleic acid and 8 mL of octadecene. First, raise the temperature to 120 °C under a nitrogen atmosphere and stir for 30 min, then continue to raise the temperature to 150 °C and stir to obtain a cesium oleate precursor solution; in the copper iodide precursor solution obtained in S1, add 2 mL of the cesium oleate precursor solution preheated to 120 °C. After reacting for 30 s, stir vigorously and cool down to 20 °C in an ice-water bath, centrifuge at 9000 rpm for 5 min, collect the precipitate and disperse it in cyclohexane, then centrifuge at 10000 rpm for 5 min, and collect the supernatant to obtain a Cs 3 Cu 2 I 5 nanocrystal solution; wherein, Cs 3 Cu 2 I 5The emission peak position of the nanocrystals is 440 nm, and the quantum efficiency is 72.2%;

[0040] S3 First, dissolve 2.0 g of EVA in 10 mL of cyclohexane to obtain a colloidal EVA organic solution, and then disperse it in the Cs 3 Cu 2 I 5 nanocrystal solution, and control the volume ratio of the EVA organic solution to the Cs 3 Cu 2 I 5 nanocrystal solution to be 1.0:1.0, mix them to obtain a cesium copper iodide nanocrystal-embedded polymer composite material. When in use, transfer the cesium copper iodide nanocrystal-embedded polymer composite material to a petri dish and slowly evaporate it at room temperature in a fume hood to obtain a nanocrystal-embedded polymer composite film for X-ray scintillator imaging.

[0041] Example 3: A preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material disclosed in the present invention, which is different from Example 1 in that

[0042] S1 Add 0.15 g of cuprous iodide, 0.19 g of zinc iodide, 0.80 mL of oleic acid, 1.00 mL of oleylamine and 15 mL of octadecene to a reaction vessel and mix them. After exhausting to vacuum, first heat up to 120 °C, and after the temperature is stable, then heat up to 180 °C until the cuprous iodide is completely dissolved to obtain a copper iodide precursor solution;

[0043] S2 Mix 0.72 g of cesium carbonate, 3.00 mL of oleic acid and 8 mL of octadecene, first heat up to 120 °C under a nitrogen atmosphere and stir for 30 min, then continue to heat up to 150 °C and stir to obtain a cesium oleate precursor solution; add 2 mL of the preheated cesium oleate precursor solution at 120 °C to the copper iodide precursor solution obtained in S1, react for 30 s, then stir vigorously and cool down to 20 °C in an ice-water bath, centrifuge at 9000 rpm for 5 min, collect the precipitate and disperse it in cyclohexane, then centrifuge at 10000 rpm for 5 min, and collect the supernatant to obtain a Cs 3 Cu 2 I 5 nanocrystal solution; wherein, the Cs 3 Cu 2 I 5 The emission peak position of the nanocrystals is 440 nm, and the quantum efficiency is 92.8%;

[0044] S3 First, dissolve 2.0 g of EVA in 10 mL of cyclohexane to obtain a colloidal EVA organic solution, and then disperse it in the Cs 3 Cu 2 I 5In the nanocrystal solution, control the EVA organic solution and Cs 3 Cu 2 I 5 The volume ratio of the nanocrystal solution is 1.0:1.0, mix them to obtain cesium copper iodide nanocrystal-embedded polymer composite material. When in use, transfer the cesium copper iodide nanocrystal-embedded polymer composite material to a petri dish and slowly evaporate it at room temperature in a fume hood, then a nanocrystal-embedded polymer composite film for X-ray scintillator imaging can be prepared. The emission peak position of the composite film is 440 nm and the quantum efficiency is 97.2%.

[0045] Example 4: A preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material disclosed in the present invention, which is different from Example 1 in that

[0046] S1 Add 0.10 g of cuprous iodide, 2.55 g of zinc iodide, 0.60 mL of oleic acid, 0.90 mL of oleylamine and 10 mL of octadecene into a reaction vessel and mix them. After exhausting to vacuum, first heat up to 115 °C. After the temperature is stable, then heat up to 160 °C until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution;

[0047] S2 Mix 0.60 g of cesium carbonate, 2.50 mL of oleic acid and 6 mL of octadecene. First heat up to 110 °C under a nitrogen atmosphere and stir for 25 min, then continue to heat up to 130 °C and stir to obtain a cesium oleate precursor solution; Add 2 mL of the cesium oleate precursor solution preheated to 115 °C into the copper iodide precursor solution obtained in S1. After reacting for 25 s, stir vigorously and cool down to 15 °C in an ice-water bath, centrifuge at 6000 rpm for 6 min, collect the precipitate and disperse it in toluene, then centrifuge at 9000 rpm for 4 min, collect the supernatant to obtain a Cs 3 Cu 2 I 5 nanocrystal solution;

[0048] S3 First dissolve 1.8 g of EVA in 8 mL of toluene to obtain a colloidal EVA organic solution, and then disperse it in the Cs 3 Cu 2 I 5 nanocrystal solution obtained in S2. Control the volume ratio of the EVA organic solution and the Cs 3 Cu 2 I 5 nanocrystal solution to be 0.8:3.0, mix them to obtain a cesium copper iodide nanocrystal-embedded polymer composite material. When in use, transfer the cesium copper iodide nanocrystal-embedded polymer composite material to a petri dish and slowly evaporate it at room temperature in a fume hood, then a nanocrystal-embedded polymer composite film for X-ray scintillator imaging can be prepared.

[0049] Example 5: A preparation method of cesium copper iodide nanocrystal-embedded polymer composite material disclosed by the present invention, which is different from Example 1 in that

[0050] S1 Add 0.20 g of cuprous iodide, 2.00 g of zinc iodide, 0.70 mL of oleic acid, 1.20 mL of oleylamine and 12 mL of octadecene into a reaction vessel and mix. After exhausting to vacuum, first heat to 105 °C. After the temperature is stable, then heat to 180 °C until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution;

[0051] S2 Mix 0.80 g of cesium carbonate, 2.80 mL of oleic acid and 5 mL of octadecene. First heat to 100 °C under a nitrogen atmosphere and stir for 35 min, then continue to heat to 140 °C and stir to obtain a cesium oleate precursor solution; Add 2 mL of the cesium oleate precursor solution preheated to 135 °C into the copper iodide precursor solution obtained in S1. After reacting for 20 s, stir vigorously and cool to 10 °C in an ice-water bath, centrifuge at 8000 rpm for 5 min, collect the precipitate and disperse it in toluene, then centrifuge at 6000 rpm for 6 min, collect the supernatant to obtain a Cs 3 Cu 2 I 5 nanocrystal solution;

[0052] S3 First dissolve 2.1 g of EVA in 15 mL of toluene to obtain a colloidal EVA organic solution, and then disperse it in the Cs 3 Cu 2 I 5 nanocrystal solution obtained in S2, control the volume ratio of the EVA organic solution to the Cs 3 Cu 2 I 5 nanocrystal solution to be 0.9:5.0, mix to obtain a cesium copper iodide nanocrystal-embedded polymer composite material. When in use, transfer the cesium copper iodide nanocrystal-embedded polymer composite material to a petri dish and slowly evaporate it at room temperature in a fume hood to obtain a nanocrystal-embedded polymer composite film for X-ray scintillator imaging.

[0053] Example 6: A preparation method of cesium copper iodide nanocrystal-embedded polymer composite material disclosed by the present invention, which is different from Example 1 in that

[0054] S1 Add 0.12 g of cuprous iodide, 0.10 g of zinc iodide, 1.00 mL of oleic acid, 0.80 mL of oleylamine and 18 mL of octadecene into a reaction vessel and mix. After exhausting to vacuum, first heat to 100 °C. After the temperature is stable, then heat to 150 °C until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution;

[0055] S2 Mix 0.65 g of cesium carbonate, 3.50 mL of oleic acid, and 10 mL of octadecene. First, heat the mixture to 130 °C under a nitrogen atmosphere and stir for 40 min. Then, continue to heat to 160 °C and stir to obtain a cesium oleate precursor solution. Add 2 mL of the preheated cesium oleate precursor solution (heated to 100 °C) to the copper iodide precursor solution obtained in S1. After reacting for 35 s, stir vigorously and cool to 30 °C in an ice-water bath. Centrifuge at 10000 rpm for 3 min, collect the precipitate, disperse it in octane, and then centrifuge at 8000 rpm for 5 min. Collect the supernatant to obtain a Cs 3 Cu 2 I 5 nanocrystal solution;

[0056] S3 First, dissolve 2.2 g of EVA in 5 mL of octane to obtain a colloidal EVA organic solution, and then disperse it in the Cs 3 Cu 2 I 5 nanocrystal solution obtained in S2. Control the volume ratio of the EVA organic solution to the Cs 3 Cu 2 I 5 nanocrystal solution to be 1.1:4.0, and mix to obtain a cesium copper iodide nanocrystal-embedded polymer composite material. When in use, transfer the cesium copper iodide nanocrystal-embedded polymer composite material to a petri dish and slowly evaporate it at room temperature in a fume hood to obtain a nanocrystal-embedded polymer composite film for X-ray scintillator imaging.

[0057] Example 7: A preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material disclosed in the present invention. The difference from Example 1 is that

[0058] S1 Add 0.18 g of cuprous iodide, 1.25 g of zinc iodide, 0.90 mL of oleic acid, 1.10 mL of oleylamine, and 20 mL of octadecene to a reaction vessel and mix. After evacuating to vacuum, first heat to 125 °C. After the temperature stabilizes, then heat to 165 °C until the cuprous iodide is completely dissolved to obtain a copper iodide precursor solution;

[0059] S2 Mix 0.75 g of cesium carbonate, 3.00 mL of oleic acid, and 7 mL of octadecene. First, heat the mixture to 140 °C under a nitrogen atmosphere and stir for 20 min. Then, continue to heat to 170 °C and stir to obtain a cesium oleate precursor solution. Add 2 mL of the preheated cesium oleate precursor solution (heated to 140 °C) to the copper iodide precursor solution obtained in S1. After reacting for 40 s, stir vigorously and cool to 25 °C in an ice-water bath. Centrifuge at 7000 rpm for 4 min, collect the precipitate, disperse it in octane, and then centrifuge at 7000 rpm for 5 min. Collect the supernatant to obtain a Cs 3 Cu 2 I5 Nanocrystalline solution;

[0060] S3 First, dissolve 1.9 g of EVA in 12 mL of octane to obtain a colloidal EVA organic solution, and then disperse it in the Cs 3 Cu 2 I 5 nanocrystalline solution, and control the volume ratio of the EVA organic solution to Cs 3 Cu 2 I 5 nanocrystalline solution to be 1.0:2.5, mix them to obtain a cesium copper iodide nanocrystal-embedded polymer composite material. When in use, transfer the cesium copper iodide nanocrystal-embedded polymer composite material to a petri dish and slowly evaporate it at room temperature in a fume hood to obtain a nanocrystal-embedded polymer composite film for X-ray scintillator imaging.

[0061] Example 8: A preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material disclosed in the present invention, which is different from Example 1 in that,

[0062] S1 Add 0.16 g of cuprous iodide, 1.80 g of zinc iodide, 0.80 mL of oleic acid, 0.80 mL of oleylamine and 16 mL of octadecene to a reaction vessel and mix them. After evacuating to vacuum, first heat up to 130 °C. After the temperature is stable, then heat up to 175 °C until the cuprous iodide is completely dissolved to obtain a copper iodide precursor solution;

[0063] S2 Mix 0.70 g of cesium carbonate, 3.20 mL of oleic acid and 9 mL of octadecene. First, heat up to 125 °C under a nitrogen atmosphere and stir for 30 min, then continue to heat up to 165 °C and stir to obtain a cesium oleate precursor solution; add 2 mL of the preheated cesium oleate precursor solution to the copper iodide precursor solution obtained in S1. After reacting for 25 s, stir vigorously and cool down to 25 °C in an ice-water bath, centrifuge at 8000 rpm for 4 min, collect the precipitate and disperse it in cyclohexane, then centrifuge at 8000 rpm for 3 min, collect the supernatant to obtain Cs 3 Cu 2 I 5 nanocrystalline solution;

[0064] S3 First, dissolve 2.0 g of EVA in 6 mL of cyclohexane to obtain a colloidal EVA organic solution, and then disperse it in the Cs 3 Cu 2 I 5 nanocrystalline solution, and control the EVA organic solution and Cs 3 Cu 2 I 5The volume ratio of the nanocrystal solution is 1.2:3.5. After mixing, a cesium copper iodide nanocrystal-embedded polymer composite material is obtained. When in use, the cesium copper iodide nanocrystal-embedded polymer composite material is transferred to a petri dish and slowly evaporated at room temperature in a fume hood, and a nanocrystal-embedded polymer composite film for X-ray scintillator imaging can be prepared.

[0065] Performance detection test

[0066] The liquid sample of the prepared cesium copper iodide nanocrystal-embedded polymer composite material is analyzed by transmission electron microscopy (TEM), where Figure 3 is the TEM image of the zinc-free doped cesium copper iodide nanocrystals (Un-doped) prepared in Example 2, Figure 4 is the TEM image of the zinc-doped cesium copper iodide nanocrystals (Zn 2+ doped) prepared in Example 3. The average particle sizes of the undoped and Zn-doped cesium copper iodide nanocrystals are calculated to be 27.2 nm and 16.5 nm respectively by particle size analysis software (DigitalMicrograph). 2+ The average particle sizes of the undoped and Zn-doped cesium copper iodide nanocrystals are calculated to be 27.2 nm and 16.5 nm respectively by particle size analysis software (DigitalMicrograph).

[0067] Under excitation at a wavelength of 290 nm, the photoluminescence quantum efficiency is obtained by a HAMAMATSU Quantaurus-QY spectrometer equipped with an integrating sphere. The radioluminescence spectrum is obtained by an X-ray imaging optical system equipped with an X-ray source (Amptek Mini X with an Ag target and a maximum power output of 4 W). The X-ray response intensity is checked and collected by an Ocean spectrometer (QEPro). The X-ray dose rate is changed by adjusting the current of the X-ray tube from 5 μA to 79 μA and calibrated by a high-sensitivity X-ray ion chamber dosimeter (Radcal Corporation). The object and the scintillator wafer are placed perpendicular to the incident X-ray, and the scintillator is fixed behind the object. A reflector is used to deflect the optical path by 90° to reduce the negative impact of direct X-ray radiation on the camera. To collect X-ray images, a CMOS camera (Photometrics 95B) with 1200×1200 pixels and a pixel size of 11 μm is equipped.

[0068] The preferred embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Any experimental and technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning or limited experiments should be within the protection scope determined by the claims.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A preparation method of cesium copper iodide nanocrystal-embedded polymer composite material, characterized in that: It includes the following steps, S1: After mixing cuprous iodide, zinc iodide, oleic acid, oleylamine and octadecene, heat up to completely dissolve cuprous iodide to obtain a copper iodide precursor solution; In the copper iodide precursor solution obtained in S1, add the preheated cesium oleate precursor solution. After the reaction ends, through post-treatment, a Cs 2+ Cu 2 I 5 nanocrystal solution doped with Zn ions is obtained. 2+ ions 3 Cu 2 I 5 ; S3 the Cs obtained in S2 3 Cu 2 I 5 A nanocrystalline solution is added with an EVA organic solution and mixed to obtain a cesium copper iodide nanocrystal-embedded polymer composite material; In the S1, the mass-volume ratio of cuprous iodide, zinc iodide, oleic acid, oleylamine and octadecene is (0.10~0.20) g:(0.10~2.55) g:(0.60~1.00) mL:(0.80~1.20) mL:(10~20) mL; In the S2, the cesium oleate precursor solution is prepared from raw materials including cesium carbonate, oleic acid and octadecene; In the S2, the mass-volume ratio of cesium carbonate, oleic acid and octadecene is (0.60~0.80) g:(2.50~3.50) mL:(5~10) mL; In S3, the organic solvent is toluene, octane or cyclohexane, and the mass-volume ratio of EVA to the organic solvent is (1.8~2.2) g : (5~15) mL. The volume ratio of the EVA organic solution to the Cs 3 Cu 2 I 5 nanocrystal solution is (0.8~1.2) : (1.0~5.0); In the step S3, first, EVA is dissolved in an organic solvent to obtain a colloidal EVA organic solution, and then it is dispersed in the Cs 3 Cu 2 I 5 nanocrystal solution and mixed to obtain a cesium copper iodide nanocrystal-embedded polymer composite material; During use, transfer the cesium copper iodide nanocrystal-embedded polymer composite material to a petri dish and slowly evaporate it at room temperature in a fume hood to obtain a nanocrystal-embedded polymer composite film for X-ray scintillator imaging; The contact angle of the composite film > 100°, and the PLQY under excitation at a wavelength of 290 nm > 65%, and the fluorescence decay lifetime is 3.7 μs, which is suitable for applications in the direction of X-ray detection; The composite film can distinguish a test area with a spatial resolution as high as 15.7 lp mm under X-ray irradiation at 50 keV -1 and has a detection limit of 0.31 μGy air s -1 .

2. The preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material according to claim 1, characterized in that: In the S1, add cuprous iodide, zinc iodide, oleic acid, oleylamine and octadecene into a reaction vessel and mix. After exhausting, first heat up to 100~130 °C. After the temperature is stable, then heat up to 150~180 °C until cuprous iodide is completely dissolved to obtain a copper iodide precursor solution.

3. The preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material according to claim 1, characterized in that: In the S2, the preparation process of the cesium oleate precursor solution includes mixing cesium carbonate, oleic acid and octadecene, first heating up to 100~140 °C under a nitrogen atmosphere and stirring for 20~40 min, and then continuing to heat up to 130~170 °C and stirring to obtain a cesium oleate precursor solution.

4. The preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material according to claim 1, characterized in that: In S2, into the copper iodide precursor solution obtained in S1, add the cesium oleate precursor solution preheated to 100~140 °C. After reacting for 20~40 s, stir and cool down to 10~30 °C, centrifuge to collect the precipitate and disperse it in an organic solvent, and then centrifuge again to collect the supernatant to obtain the Cs 3 Cu 2 I 5 nanocrystal solution.

5. The preparation method of a cesium copper iodide nanocrystal-embedded polymer composite material according to claim 4, characterized in that: In the S2, control the centrifugation speed to be 6000~10000 rpm / min and the time to be 3~6 min, and the organic solvent is toluene, octane or cyclohexane.

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