阅读说明：本技术 ZnO-Ga聚合物闪烁转换屏的制备方法 (Preparation method of ZnO-Ga polymer scintillation conversion screen ) 是由 李乾利 杨道龙 张志军 赵景泰 杨云凌 袁瑞 杨雪纯 周玉 于 2019-09-02 设计创作，主要内容包括：本发明公开了一种ZnO-Ga聚合物闪烁转换屏的制备方法,能制备超快ZnO-Ga闪烁转换屏。本发明利用水热反应法制备ZnO-Ga纳米晶,然后主要采用树脂、聚苯乙烯或有机玻璃作为有机体材料,使ZnO-Ga纳米晶通过与有机体材料的结合,制备ZnO-Ga聚合物闪烁体。利用本发明方法获得ZnO-Ga闪烁体没有缺陷发光,慢成分,发光衰减时间在几十纳秒,只有禁带边超快发光,其发光衰减时间达到亚纳秒。同时,其厚度和直径尺寸能根据实际需要方便调控,适应性强,应用广泛。本发明方法不仅制备过程简单、成本低廉、制备周期短,而且具有良好的闪烁发光性能以及能制备出各种尺寸和不同厚度的闪烁转换屏的优势。(The invention discloses a preparation method of a ZnO-Ga polymer scintillation conversion screen, which can be used for preparing an ultrafast ZnO-Ga scintillation conversion screen. The invention utilizes a hydrothermal reaction method to prepare ZnO-Ga nanocrystals, and then mainly adopts resin, polystyrene or organic glass as an organic material, so that the ZnO-Ga nanocrystals are combined with the organic material to prepare the ZnO-Ga polymer scintillator. The ZnO-Ga scintillator obtained by the method has no defect luminescence and slow components, the luminescence decay time is dozens of nanoseconds, only the forbidden band edge emits ultrafast luminescence, and the luminescence decay time reaches subnanoseconds. Meanwhile, the thickness and the diameter of the composite material can be conveniently regulated and controlled according to actual needs, and the composite material is strong in adaptability and wide in application. The method has the advantages of simple preparation process, low cost, short preparation period, good scintillation luminescence property and capability of preparing scintillation conversion screens with various sizes and different thicknesses.)

1. A preparation method of a ZnO-Ga polymer scintillation conversion screen is characterized by comprising the following steps: the method comprises the following steps:

1) preparing ZnO-Ga nanocrystalline powder:

ga (NO) with a certain molar mass₃)₃·xH₂O and Zn (NO)₃)·6H₂O and C₆H₁₂N₁₄Dissolving in deionized water respectively, mixing to obtain reactant solution, and making Ga (NO)₃)₃、Zn(NO₃) And C₆H₁₂N₁₄The total molar concentration of the solute is 0.01-0.5 mol/L; then introducing the mixed solution into a hydrothermal reaction kettle, putting the reaction kettle into a heat preservation box, heating to 95-150 ℃, carrying out hydrothermal reaction for 6-20 h, and preparing the ZnO-Ga single crystal nanorod by using a hydrothermal reaction method;

2) multistage annealing treatment of ZnO-Ga nanocrystalline powder: the method comprises the following steps:

2-1) carrying out first high-temperature annealing treatment on the ZnO-Ga single crystal nanorod prepared by the hydrothermal reaction method in the step 1) in air, wherein the annealing temperature is controlled to be 500-1000 ℃, and the annealing treatment time is 5-30 h;

2-2) then putting the ZnO-Ga single crystal nanorod subjected to air annealing treatment in the step 2-1) into a hydrogen-argon mixed gas for secondary high-temperature annealing treatment, controlling the annealing temperature to be 500-1000 ℃, and annealing for 1-5 h to obtain ZnO-Ga single crystal nanorod powder;

3) preparing a ZnO-Ga polymer scintillation conversion screen:

mixing the ZnO-Ga single crystal nanorod powder obtained in the step 2-2) with an organic material and a curing agent, and controlling the content ratio of the ZnO-Ga single crystal nanorod powder in the mixture to be 0.1-50 wt%; firstly, uniformly mixing the mixture by using a magnetic stirrer; removing bubbles in the mixture by using a vacuum drying oven; filling the mixture into a mold with a set inner diameter, putting the connected mold into a drying box, curing, and demolding to prepare the ZnO-Ga polymer scintillator; and finally, cutting the prepared ZnO-Ga polymer scintillator into sheets by using a wire cutting machine, and polishing to obtain the ZnO-Ga polymer scintillation conversion screen with the required thickness.

2. The method for preparing a ZnO-Ga polymer scintillation conversion screen of claim 1, wherein the method comprises the following steps: and 3) obtaining the ZnO-Ga polymer scintillation conversion screen with the thickness not less than 0.5 mm.

3. The method for preparing a ZnO-Ga polymer scintillation conversion screen of claim 1, wherein the method comprises the following steps: and 3) obtaining the circular ZnO-Ga polymer scintillation conversion screen with the diameter not less than 50 mm.

4. The method for preparing a ZnO-Ga polymer scintillation conversion screen of claim 1, wherein the method comprises the following steps: in the step 3), the ZnO-Ga single crystal nanorod powder obtained in the step 2-2) is mixed with the resin and the curing agent, and the content ratio of the ZnO-Ga single crystal nanorod powder in the mixture is controlled to be 12.5-50 wt%.

5. The method for preparing a ZnO-Ga polymer scintillation conversion screen of claim 1, wherein the method comprises the following steps: in the step 3), the organic material is resin, polystyrene or organic glass.

6. The method for preparing a ZnO-Ga polymer scintillation conversion screen of claim 1, wherein the method comprises the following steps: in the step 1), heating is controlled to 120-150 ℃, a hydrothermal reaction is carried out for 12-20 h, and the ZnO-Ga single crystal nanorod is prepared by a hydrothermal reaction method.

Technical Field

The invention relates to a preparation method of a scintillation material, in particular to a preparation method of a ZnO-Ga scintillation conversion screen with quick response, which is applied to the technical field of scintillation detection and imaging.

Background

The scintillating material is a material that emits ultraviolet or visible light by absorbing energetic particles or rays. In the fields of high-energy physics, space physics, nuclear medicine imaging, oil well detection, safety inspection, industrial CT, life science and the like, a scintillation conversion screen composed of a scintillation material is a core device for realizing detection and imaging of X rays, gamma rays or high-energy particles. The main indexes for evaluating the performance of the scintillation screen comprise light yield, decay time, spatial resolution, cut-off power, radiation hardness and the like. The acquisition of the ultrafast scintillation screen with the subnanosecond-level decay time is a long-sought target of people so as to meet the requirements of ultrafast scintillation detection and imaging in the future.

ZnO is a novel wide-band-gap direct transition semiconductor material, and the exciton oscillator intensity coupling enhancement effect in the range of multiple primitive cells in the material enables the light-emitting decay time to be in a subnanosecond level, so that ZnO is one of scintillation materials with the highest decay speed. ZnO exists in nature stably, and has no toxicity and odor, melting point of 1975 deg.C, and density of 5.606g/cm 3. The band gap width at room temperature was 3.37eV, and the exciton confinement energy was 60 meV. ZnO has excellent optical performance at room temperature, and can improve the luminous performance of ZnO due to large exciton confinement energy and radiation resistance intensity, such as Ga and In, and is expected to be used for various radiation detections. The ideal ZnO material is a room temperature scintillator with high speed and high light output efficiency, has stronger radiation resistance than GaAs and GaN, can be used in a strong radiation environment, and particularly has ultrashort scintillation decay time, which is always the focus of nuclear science research. The ZnO material has extremely important practical value as the next generation ultrafast scintillator.

Although the current hydrothermal method can grow good large-sized ZnO-Ga crystals, it is difficult to produce single crystals with sufficiently large crystal size and good performance due to the crystal habit of ZnO-Ga. Large size single crystal material growth often requires special expensive equipment that not only needs to withstand high temperatures, high pressures, but also special metals to protect the liner from the mineralizer. Meanwhile, the ZnO-Ga crystal growth process is very complex, the growth period is too long due to slow growth speed, a large amount of time is needed to obtain the crystal meeting the requirements, even about months, the manufacturing cost is very expensive, the rejection rate is high, and the requirement of industrial production cannot be met. In addition, the ZnO-Ga material has serious self-absorption problem, and if a large ZnO-Ga crystal is directly used for scintillation detection and imaging, the self-absorption of the ZnO-Ga crystal can cause the luminous efficiency to be greatly reduced. A method for eliminating ZnO self-absorption is to use the ZnO as a hundred micron thin sheet. However, the ZnO-Ga crystal is difficult and expensive to process because the crystal is generally very brittle, which causes the crystal to be easily broken by the polishing process. In contrast, the general ZnO — Ga thin film preparation method includes, for example: the ZnO-Ga film obtained by a magnetron sputtering method, a pulse laser deposition method and the like is usually between dozens of nanometers and dozens of micrometers, and the scintillation property is poor, so that the ZnO-Ga film with high quality in the order of hundreds of micrometers is difficult to obtain.

Disclosure of Invention

In order to solve the problems of the prior art, the invention aims to overcome the defects of the prior art and provide a preparation method of a ZnO-Ga polymer scintillation conversion screen. The ZnO-Ga scintillator obtained by the method has no defect, no luminescence, slow component, and the luminescence decay time of dozens of nanoseconds, only the forbidden band edge emits ultrafast light, and the luminescence decay time reaches subnanosecond, and the quality is high. Meanwhile, the thickness and the diameter of the ZnO-Ga polymer scintillation conversion screen prepared by the invention can be conveniently regulated and controlled according to actual needs, and the ZnO-Ga polymer scintillation conversion screen has strong adaptability and wide application.

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

a preparation method of a ZnO-Ga polymer scintillation conversion screen comprises the following steps:

1) preparing ZnO-Ga nanocrystalline powder:

ga (NO) with a certain molar mass₃)₃·xH₂O and Zn (NO)₃)·6H₂O and C₆H₁₂N₁₄Dissolving in deionized water respectively, mixing to obtain reactant solution, and making Ga (NO)₃)₃、Zn(NO₃) And C₆H₁₂N₁₄The total molar concentration of the solute is 0.01-0.5 mol/L; then introducing the mixed solution into a hydrothermal reaction kettle, putting the reaction kettle into a heat preservation box, heating to 95-150 ℃, carrying out hydrothermal reaction for 6-20 h, and preparing the ZnO-Ga single crystal nanorod by using a hydrothermal reaction method; as the preferred technical scheme of the invention, the heating is controlled to 120-150 ℃, the hydrothermal reaction is carried out for 12-20 h, and the ZnO-Ga single crystal nanorod is prepared by using a hydrothermal reaction method;

2) multistage annealing treatment of ZnO-Ga nanocrystalline powder: the method comprises the following steps:

2-1) carrying out first high-temperature annealing treatment on the ZnO-Ga single crystal nanorod prepared by the hydrothermal reaction method in the step 1) in air, wherein the annealing temperature is controlled to be 500-1000 ℃, and the annealing treatment time is 5-30 h;

2-2) then putting the ZnO-Ga single crystal nanorod subjected to air annealing treatment in the step 2-1) into a hydrogen-argon mixed gas for secondary high-temperature annealing treatment, controlling the annealing temperature to be 500-1000 ℃, and annealing for 1-5 h to obtain ZnO-Ga single crystal nanorod powder;

3) preparing a ZnO-Ga polymer scintillation conversion screen:

mixing the ZnO-Ga single crystal nanorod powder obtained in the step 2-2) with an organic material and a curing agent, and controlling the content ratio of the ZnO-Ga single crystal nanorod powder in the mixture to be 0.1-50 wt%; firstly, uniformly mixing the mixture by using a magnetic stirrer; removing bubbles in the mixture by using a vacuum drying oven; filling the mixture into a mold with a set inner diameter, putting the connected mold into a drying box, curing, and demolding to prepare the ZnO-Ga polymer scintillator; and finally, cutting the prepared ZnO-Ga polymer scintillator into sheets by using a wire cutting machine, and polishing to obtain the ZnO-Ga polymer scintillation conversion screen with the required thickness. Preferably, the ZnO-Ga polymer scintillation conversion screen with the thickness of not less than 0.5mm is obtained. The circular ZnO-Ga polymer scintillation conversion screen with the diameter of not less than 50mm is preferably obtained. As a preferable technical scheme of the invention, the ZnO-Ga single crystal nanorod powder obtained in the step 2-2) is mixed with the resin and the curing agent, and the content ratio of the ZnO-Ga single crystal nanorod powder in the mixture is controlled to be 12.5-50 wt%. The organic material is preferably resin, polystyrene or organic glass.

Compared with the prior art, the invention has the following obvious and prominent substantive characteristics and remarkable advantages:

1. the method of the invention uses a hydrothermal reaction method to prepare ZnO-Ga nanocrystalline, then mainly uses resin, polystyrene or organic glass as organic material, so that the ZnO-Ga nanocrystalline is combined with the organic material to prepare ZnO-Ga polymer scintillator, then the ZnO-Ga polymer scintillator is cut into slices by a wire cutting machine, and then the slices are polished to obtain the ZnO-Ga polymer scintillation conversion screen, and the preparation method has the advantages of simple process, low cost, short preparation period, easy realization and suitability for popularization and application;

2. the ZnO-Ga polymer scintillation conversion screen prepared by the method has good scintillation luminescence performance, and the method can prepare the scintillation conversion screens with various sizes and different thicknesses;

3. the method adopts the multi-stage annealing treatment of ZnO-Ga nanocrystalline powder; firstly, improving the crystallization performance of ZnO-Ga nanocrystalline powder through air annealing; then, by annealing with hydrogen-argon mixture, the ultra-fast component (forbidden band edge) luminescence of the material is improved, and the slow component (defect) luminescence of the material is reduced; thereby realizing the optimization of the scintillation property of the ZnO-Ga nanocrystalline powder and obtaining the ZnO-Ga monocrystalline nanorod powder with excellent scintillation property.

Drawings

FIG. 1 is an SEM image of ZnO-Ga single crystal nanorod powder prepared by a method in an embodiment of the invention.

FIG. 2 is an XRD pattern of ZnO-Ga single crystal nanorod powder prepared by a method in an embodiment of the invention.

FIG. 3 is a diagram of a ZnO-Ga polymer scintillation conversion screen prepared by a method in an embodiment of the invention.

FIG. 4 is a transmittance spectrum of a ZnO-Ga polymer scintillation conversion screen prepared by a method in an embodiment of the invention.

FIG. 5 is an X-ray excitation emission spectrum of a ZnO-Ga polymer scintillation conversion screen prepared by a method in an embodiment of the invention.

FIG. 6 is a luminescence decay time spectrum of a ZnO-Ga polymer scintillation conversion screen prepared by a method in an embodiment of the invention.

FIG. 7 is an SEM image of ZnO-Ga single crystal nanorod powder prepared by the second method in the example of the invention.

FIG. 8 is a diagram of a ZnO-Ga polymer scintillation conversion screen prepared by the second method in the embodiment of the invention.

FIG. 9 is a diagram of a ZnO-Ga polymer scintillation conversion screen prepared by a tetragonal method in accordance with an embodiment of the present invention.

FIG. 10 is a diagram of a ZnO-Ga polymer scintillation conversion screen prepared by the fifth method in the embodiment of the invention.

Detailed Description

The above-described scheme is further illustrated below with reference to specific embodiments, which are detailed below: