阅读说明：本技术 一种应用于x射线成像的透明钙钛矿/聚合物闪烁屏的制备方法 (Preparation method of transparent perovskite/polymer scintillation screen applied to X-ray imaging ) 是由 杨智 郭威 汪敏强 于 2021-10-19 设计创作，主要内容包括：本发明公开了一种应用于X射线成像的透明钙钛矿/聚合物闪烁屏的制备方法,包括以下步骤：将透明聚合物基底浸入钙钛矿的DMF溶液,然后装入反应釜中；将反应釜在60～200℃下反应10～6000min,然后将透明聚合物基底经异丙醇浸泡后干燥,最后将多片透明聚合物基底热压或粘结的方式叠放制成厚闪烁屏。本发明制备的柔性大面积闪烁屏具有高光子产额、高透光率、高成像分辨率和可调发光波长。开发的浸染工艺重复性高、可靠性强、适合于大面积均匀钙钛矿闪烁屏的制备,有望应用于曲面X射线成像,以降低边缘成像畸变。(The invention discloses a preparation method of a transparent perovskite/polymer scintillation screen applied to X-ray imaging, which comprises the following steps: immersing a transparent polymer substrate into a DMF solution of perovskite, and then filling the solution into a reaction kettle; and (3) reacting the reaction kettle at 60-200 ℃ for 10-6000 min, soaking the transparent polymer substrate in isopropanol, drying, and finally stacking a plurality of transparent polymer substrates in a hot pressing or bonding mode to prepare the thick scintillation screen. The flexible large-area scintillation screen prepared by the invention has high photon yield, high light transmittance, high imaging resolution and adjustable luminescence wavelength. The developed dip dyeing process has high repeatability and strong reliability, is suitable for preparing large-area uniform perovskite scintillation screens, and is expected to be applied to curved surface X-ray imaging so as to reduce edge imaging distortion.)

1. A preparation method of a transparent perovskite/polymer scintillation screen applied to X-ray imaging is characterized by comprising the following steps:

immersing a transparent polymer substrate into a DMF solution of perovskite, and then filling the solution into a reaction kettle; and (3) reacting the reaction kettle at 60-200 ℃ for 10-6000 min, soaking the transparent polymer substrate in isopropanol, drying, and finally stacking a plurality of transparent polymer substrates in a hot pressing or bonding mode to prepare the thick scintillation screen.

2. The method according to claim 1, wherein the perovskite is MAPbBr₃、(PEA)₂PbI₄、(PEA)₂PbBr₄、CsCu₂I₃、Cs₃Cu₂I₅Or Rb₂CuBr₃。

3. The method for preparing a transparent perovskite/polymer scintillation screen applied to X-ray imaging according to claim 1, wherein the concentration of the DMF solution of the perovskite is 0.01-1 mol/L.

4. The method of claim 1, wherein the transparent polymer substrate is polyethylene terephthalate, polyimide, polystyrene or polycarbonate.

5. The method for preparing a transparent perovskite/polymer scintillation screen applied to X-ray imaging according to claim 1, characterized in that the thickness of the transparent polymer substrate is 0.001-10 mm.

6. The method for preparing a transparent perovskite/polymer scintillation screen applied to X-ray imaging according to claim 1, wherein the area of the polymer substrate is 1-400 cm²。

7. The preparation method of the transparent perovskite/polymer scintillation screen applied to X-ray imaging according to claim 1, wherein the temperature of isopropanol is 80 ℃ and the soaking time is 1-60 min.

8. The preparation method of the transparent perovskite/polymer scintillation screen applied to X-ray imaging according to claim 1, characterized in that the drying temperature is 80 ℃ and the drying time is 30-300 min.

Technical Field

The invention belongs to the field of high-energy ray detection, and particularly relates to a preparation method of a transparent perovskite/polymer scintillation screen applied to X-ray imaging.

Background

The digital X-ray imaging technology plays a great role in the fields of medicine, security inspection, industrial nondestructive inspection, industrial flaw detection and the like. X-ray imaging is based on the high penetration of X-rays on the one hand and on the difference in density and thickness of the measured substances on the other hand. Compared with direct detection, the indirect detection mode based on the scintillator can utilize a mature CCD imaging device, so that the performance of the scintillation screen is a key factor for determining the imaging quality. In a conventional X-ray scintillation screen, a reflective layer, a cesium iodide scintillator layer, and a barrier layer are sequentially deposited on a glass substrate, for example, in chinese patent CN103744104A, "X-ray cesium iodide scintillation screen". However, cesium iodide belongs to an ionic crystal, is easy to deliquesce, and has high packaging requirements. In addition, high temperature conditions are required for crystal growth, and flexible screens are difficult to achieve. At present, the large-area flexible scintillation screen is difficult to manufacture and has poor long-term stability.

Disclosure of Invention

The invention aims to provide a preparation method of a transparent perovskite/polymer scintillation screen applied to X-ray imaging, and the prepared flexible large-area scintillation screen has high photon yield, high light transmittance, high imaging resolution and adjustable luminescence wavelength. The dip dyeing process developed by the invention is characterized in that a polymer substrate is soaked in a high-temperature and high-pressure perovskite precursor solution, perovskite can permeate into polymer molecular pores, and then the perovskite is crystallized under the action of a counter solvent, so that in-situ compounding of the perovskite and the polymer is realized. The process has high repeatability and strong reliability, and is suitable for preparing large-area uniform perovskite scintillation screens.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a transparent perovskite/polymer scintillation screen applied to X-ray imaging comprises the following steps:

immersing a transparent polymer substrate into a DMF solution of perovskite, and then filling the solution into a reaction kettle; and (3) reacting the reaction kettle at 60-200 ℃ for 10-6000 min, soaking the transparent polymer substrate in isopropanol, drying, and finally stacking a plurality of transparent polymer substrates in a hot pressing or bonding mode to prepare the thick scintillation screen.

Further, the perovskite is MAPbBr₃、(PEA)₂PbI₄、(PEA)₂PbBr₄、CsCu₂I₃、Cs₃Cu₂I₅Or Rb₂CuBr₃。

Furthermore, the concentration of the DMF solution of the perovskite is 0.01-1 mol/L.

Further, the transparent polymer substrate is polyethylene terephthalate, polyimide, polystyrene, or polycarbonate.

Further, the transparent polymer substrate has a thickness of 0.001 to 10 mm.

Further, the area of the polymer substrate is 1-400 cm²。

Furthermore, the temperature of the isopropanol is 80 ℃, and the soaking time is 1-60 min.

Further, the drying temperature is 80 ℃, and the drying time is 30-300 min.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, based on the dip-dyeing principle, a polymer substrate is soaked in a high-temperature high-pressure perovskite precursor liquid, the polymer is swelled to a certain extent, then the perovskite can permeate into polymer molecular pores, and then the perovskite is crystallized under the action of an anti-solvent, so that the in-situ compounding of the perovskite and the polymer is realized. When the perovskite/polymer composite film is dried, the polymer undergoes deswelling, so that the perovskite is firmly embedded into the polymer. The polymer is a framework of the scintillation screen, the embedded perovskite can emit light under X-ray radiation, and meanwhile, the polymer can remarkably reduce the probability that the perovskite is in contact with air humidity, so that the stability of the scintillation screen is greatly improved. The perovskite/polymer scintillation screen prepared by the method has high transparency, and the photon yield of X-ray radiation can be improved through multilayer superposition; the perovskite prepared by the dip-dyeing method is uniformly distributed in the polymer, and the uniformity of a two-dimensional plane is very helpful for obtaining high imaging spatial resolution; the method is suitable for preparing large-area scintillation screens, and has process amplification and repeatability; the flexible scintillation screen can be bent at will, and can realize curved surface X-ray imaging; the perovskite/polymer scintillation screen has high environmental and working stability and can meet the requirements of engineering use.

Drawings

FIG. 1 is a schematic diagram of the structure of a transparent perovskite/polymer scintillation screen.

FIG. 2 is a 0.1mm thick PET substrate dip-dyed at various concentrations of MAPbBr₃Transmittance spectrum of the scintillation screen.

FIG. 3 is a 0.1mm thick PET substrate dip-dyed at various concentrations of MAPbBr₃Fluorescence spectrum of scintillation screen.

FIG. 4 is a graph showing the change of the long-term soaking transmittance and fluorescence spectrum of a transparent perovskite/polymer scintillation screen in water.

Fig. 5 is an X-ray image of a transparent perovskite/polymer scintillation screen.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

A preparation method of a transparent perovskite/polymer scintillation screen applied to X-ray imaging comprises the following steps:

1) immersing a transparent polymer substrate into 0.01-1 mol/L perovskite DMF solution, and putting the solution into a reaction kettle;

wherein the transparent polymer substrate is polyethylene terephthalate (PET), Polyimide (PI) or Polystyrene (PS), Polycarbonate (PC). The transparent polymer substrate has a thickness of 0.001 to 10mm and an area of 1 to 400cm²。

2) Transferring the reaction kettle to a constant temperature box, and reacting for 10-6000 min at 60-200 ℃;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 1-60 min;

4) taking out the transparent polymer substrate, and drying in a thermostat at 80 ℃ for 30-300 min;

5) and stacking a plurality of transparent polymer substrates in a hot pressing or bonding mode to manufacture the thick scintillation screen.

The perovskite component is (PEA)₂PbI₄、(PEA)₂PbBr₄、CsCu₂I₃、Cs₃Cu₂I₅Or Rb₂CuBr₃。

Example 1

1) Mixing 0.1mm thick and 4cm in area²The transparent PET substrate of (2) was immersed in 0.3mol/L MAPbBr₃Putting the DMF solution into a 50ML reaction kettle;

2) transferring the reaction kettle to a thermostat at 180 ℃ for reaction for 120 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 15 min;

4) taking out the transparent polymer substrate and drying in a thermostat at 80 ℃ for 120 min.

5) 2 pieces of PET substrate were bonded into a 0.2mm thick transparent perovskite/polymer scintillation screen.

Example 2

1) Mixing 0.1mm thick and 100cm area²The transparent PET substrate of (2) is dipped into 0.3mol/L of (PEA)₂PbI₄Putting the DMF solution into a 200ML reaction kettle;

2) transferring the reaction kettle to a thermostat at 180 ℃ for reaction for 240 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 15 min;

4) taking out the transparent polymer substrate and drying in a thermostat at 80 ℃ for 120 min.

5) The 3 sheets of PET substrate were bonded into a 0.3mm thick transparent perovskite/polymer scintillation screen.

Example 3

1) Mixing 0.1mm thick and 100cm area²The transparent PET substrate of (2) was immersed in 0.1mol/L CsCu₂I₃Putting the DMF solution into a 200ML reaction kettle;

2) transferring the reaction kettle to a constant temperature box at 160 ℃ for reaction for 100 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 30 min;

4) taking out the transparent polymer substrate and drying in a thermostat at 80 ℃ for 120 min.

5) 2 pieces of PET substrate were bonded into a 0.2mm thick transparent perovskite/polymer scintillation screen.

Example 4

1) Mixing 0.2mm thick and 100cm area²The transparent PET substrate of (2) is immersed in 0.1mol/L Cs₃Cu₂I₅Putting the DMF solution into a 200ML reaction kettle;

2) transferring the reaction kettle to a 200 ℃ thermostat to react for 100 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 30 min;

4) taking out the transparent polymer substrate and drying in a thermostat at 80 ℃ for 100 min.

5) 4 sheets of PET substrate were bonded into a 0.8mm thick transparent perovskite/polymer scintillation screen.

Example 5

1) Mixing 1mm thick and 20cm in area²The transparent PET substrate of (2) is immersed in 0.1mol/L of Rb₂CuBr₃Putting the DMF solution into a 50ML reaction kettle;

2) transferring the reaction kettle to a thermostat at 180 ℃ for reaction for 100 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 30 min;

4) taking out the transparent polymer substrate and drying in a thermostat at 80 ℃ for 120 min.

5) 2 pieces of PET substrate were bonded into a 2mm thick transparent perovskite/polymer scintillation screen.

FIG. 1 shows the structure of the perovskite/polymer scintillation screen, perovskite nanocrystals are uniformly distributed in the polymer, the uniformity of a two-dimensional imaging plane of the scintillation screen is ensured, and the high imaging spatial resolution is obtained on the premise. The quantity of perovskite nanocrystals in the transparent scintillation screen is small, so that the photon yield under X-ray radiation is low, and the superposition of multiple layers of thin screens is an important means for improving the photon yield.

As can be seen from fig. 2, the visible light transmittance of the 0.1mm pet substrate is 80%,by increasing MAPbBr₃The concentration of the perovskite precursor liquid is from 0.2M to 0.6M, and the transmittance at 500nm is increased from 20% to 72%. Increasing from 0.4M to 0.6M the transmittance curves were approximately the same, indicating that the swelling of the polymer was close to saturation, resulting in the same degree of perovskite crystallization.

As can be seen from FIG. 3, the scintillation screen prepared by using the low concentration of 0.2mol/L precursor solution has two independent fluorescence peaks of 490nm and 535nm, the scintillation screen prepared by using the concentration of 0.3mol/L has two independent fluorescence peaks of 480nm and 530nm, which indicates that the perovskite nanocrystals prepared by the dip dyeing process are not uniformly distributed in the thickness direction of the polymer substrate, the long-wave fluorescence 530nm is originated from the perovskite with large particle size on the surface of the polymer, and the short-wave fluorescence 480nm and 490nm is originated from the perovskite with small particle size in the interior of the polymer (the luminescence blue shift caused by quantum size effect). It is demonstrated that the perovskite grain size decreases gradually from the surface to the interior of the polymer, due to the fact that surface perovskites can crystallize rapidly and the interior crystallizes slowly during the anti-solvent crystallization process. As the concentration of the precursor liquid is increased, two fluorescence peaks are gradually combined to form a fluorescence peak of 505nm, and the perovskite precursor liquid is reduced in the amount and depth of being immersed into the polymer substrate due to the fact that the swelling rate of the PET substrate is reduced as the concentration of the precursor liquid is increased, and the perovskite with uniformly distributed longitudinal size and amount is obtained. In addition, different concentrations of MAPbBr₃The scintillating screens of perovskites have approximately comparable fluorescence intensities, attributed to MAPbBr₃The perovskite has only 10nm Stokes shift, so that self-absorption is strong and surface luminescence is dominant.

As can be seen from FIG. 4, the transmittance and fluorescence intensity of the perovskite/polymer scintillation screen maintain extremely small fluctuation during 100 days of soaking in water, which indicates that the polymer can be used as a waterproof barrier to fully protect the moisture-sensitive perovskite.

As can be seen from FIG. 5, the perovskite/polymer scintillation screen enables X-ray imaging of a metal spring mounted in an opaque plastic canister, taking advantage of the different penetration capabilities of X-rays through different density materials, while demonstrating the planar uniformity of the scintillation screen.

Example 6

1) Mixing 0.01mm thick and 1cm area²The transparent PI substrate is immersed in 0.001mol/L Rb₂CuBr₃Putting the DMF solution into a 50ML reaction kettle;

2) transferring the reaction kettle to a 200 ℃ thermostat for reaction for 10 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 50 min;

4) taking out the transparent polymer substrate and drying the transparent polymer substrate in a thermostat at 80 ℃ for 30 min.

5) 2 pieces of PET substrate were hot pressed into a 0.2mm thick transparent perovskite/polymer scintillation screen.

Example 7

1) Mixing 1mm thick and 400cm in area²Is dipped into 10mol/L (PEA)₂PbI₄Putting the DMF solution into a 50ML reaction kettle;

2) transferring the reaction kettle to a constant temperature box at 60 ℃ for 6000 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 40 min;

4) taking out the transparent polymer substrate and drying in a thermostat at 80 ℃ for 300 min.

5) 2 pieces of PET substrate were bonded into a 0.2mm thick transparent perovskite/polymer scintillation screen.

Example 8

1) Mixing 0.05mm thick and 200cm area²The transparent PC substrate of (2) is immersed in 0.5mol/L of (PEA)₂PbI₄Putting the DMF solution into a 50ML reaction kettle;

2) transferring the reaction kettle to a 120 ℃ thermostat to react for 3000 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 1 min;

4) taking out the transparent polymer substrate and drying in a thermostat at 80 ℃ for 200 min.

5) 2 pieces of PET substrate were bonded into a 0.2mm thick transparent perovskite/polymer scintillation screen.

Example 9

1) Mixing the mixture to obtain a mixture with a thickness of 0.7mm and an area of 50cm²The transparent PI substrate of (2) is immersed in 5mol/L of (PEA)₂PbI₄Putting the DMF solution into a 50ML reaction kettle;

2) transferring the reaction kettle to a constant temperature box at 150 ℃ for reaction for 50 min;

3) taking out the transparent polymer substrate and soaking the transparent polymer substrate in isopropanol at the temperature of 80 ℃ for 60 min;

4) taking out the transparent polymer substrate, and drying in a thermostat at 80 ℃ for 70 min.

5) 2 pieces of PET substrate were bonded into a 0.2mm thick transparent perovskite/polymer scintillation screen.

The flexible large-area scintillation screen prepared by the invention has high photon yield, high light transmittance, high imaging resolution and adjustable luminescence wavelength. The developed dip dyeing process has high repeatability and strong reliability, is suitable for preparing large-area uniform perovskite scintillation screens, and is expected to be applied to curved surface X-ray imaging so as to increase the uniform imaging field of view.