阅读说明：本技术 一种铯铅卤素钙钛矿厚膜及其制备与应用 (Cesium-lead halogen perovskite thick film and preparation and application thereof ) 是由 牛广达 唐江 潘伟程 杨波 于 2019-09-09 设计创作，主要内容包括：本发明属于以半导体材料制备的辐射探测技术领域,公开了一种铯铅卤素钙钛矿厚膜及其制备与应用,其中制备方法具体是：(1)将铯铅卤素钙钛矿材料分散在基底上,然后加热使温度升至铯铅卤素钙钛矿的熔点以上,直至铯铅卤素钙钛矿完全熔化成液态；(2)将石英片覆盖在液态的钙钛矿材料上,使被石英片覆盖的液态钙钛矿材料在所述基底上均匀分散；(3)将温度以0.1～5℃/min的速率缓慢降低进行冷却,然后将石英片揭掉,即可得到粘连在基底上的钙钛矿厚膜。本发明通过对制备方法的整体工艺流程设计(包括温度控制程序)等进行改进,能够获得高性能、取向一致、稳定的、高灵敏度大面积厚膜,解决现有技术存在的工艺复杂、灵敏度低、取向不一致等问题。(The invention belongs to the technical field of radiation detection prepared from semiconductor materials, and discloses a cesium-lead halogen perovskite thick film, and preparation and application thereof, wherein the preparation method specifically comprises the following steps: (1) dispersing a cesium-lead halogen perovskite material on a substrate, and then heating to raise the temperature to be higher than the melting point of the cesium-lead halogen perovskite until the cesium-lead halogen perovskite is completely melted into a liquid state; (2) covering the quartz plate on the liquid perovskite material to uniformly disperse the liquid perovskite material covered by the quartz plate on the substrate; (3) and slowly reducing the temperature at the speed of 0.1-5 ℃/min for cooling, and then removing the quartz plate to obtain the perovskite thick film adhered on the substrate. According to the invention, through improving the whole process flow design (including a temperature control program) and the like of the preparation method, the thick film with high performance, consistent orientation, stability, high sensitivity and large area can be obtained, and the problems of complex process, low sensitivity, inconsistent orientation and the like in the prior art are solved.)

1. A preparation method of a cesium-lead halogen perovskite thick film is characterized by comprising the following steps:

(1) placing the cesium-lead halogen perovskite material on a substrate, and then heating to raise the temperature to be higher than the melting point of the cesium-lead halogen perovskite until the cesium-lead halogen perovskite is completely melted into a liquid state;

(2) keeping the temperature above the melting point of the cesium-lead halogen perovskite, covering a quartz plate on a liquid perovskite material, and uniformly dispersing the liquid perovskite material covered by the quartz plate on the substrate;

(3) and slowly reducing the temperature at the speed of 0.1-5 ℃/min for cooling, then removing the quartz plate, and obtaining a perovskite thick film adhered on the substrate by using the inertia between the quartz plate and the cesium lead halogen perovskite, wherein the perovskite thick film is the cesium lead halogen perovskite thick film with the thickness of not less than 1 um.

2. A preparation method of a cesium-lead halogen perovskite thick film is characterized by comprising the following steps:

(1) placing cesium-lead halogen perovskite materials on a quartz plate with a groove, heating to enable the temperature to rise to be higher than the melting point of the cesium-lead halogen perovskite until the cesium-lead halogen perovskite is completely melted into a liquid state, and completely filling the groove of the quartz plate with the liquid perovskite materials;

(2) keeping the temperature above the melting point of the cesium-lead halogen perovskite, covering the substrate on the liquid perovskite material, and uniformly dispersing the liquid perovskite material in a groove space formed by surrounding the substrate and the quartz plate;

(3) and slowly reducing the temperature at the speed of 0.1-5 ℃/min for cooling, then taking down the quartz plate, and obtaining the perovskite thick film adhered on the substrate by using the inertia between the quartz plate and the cesium lead halogen perovskite, wherein the perovskite thick film is the cesium lead halogen perovskite thick film with the thickness of not less than 1 um.

3. The method of preparing a cesium lead halide perovskite thick film as claimed in claim 1 or 2, wherein in said step (1), step (1) is carried outThe cesium lead halogen perovskite is cesium lead iodide CsPbI₃Cesium lead bromide CsPbBr₃Cesium lead chloride CsPbCl₃Or cesium lead iodide bromide CsPbI_xBr_(3-x)(ii) a Preferably, the cesium lead iodide bromide CsPbI_xBr_(3-x)Middle, 0<x<3。

4. The method of making a cesium lead halide perovskite thick film of claim 1 or 2, wherein said substrate is an FTO transparent conductive glass substrate, or a boron nitride substrate.

5. The method of preparing a thick cesium lead halide perovskite film as claimed in claim 1, wherein said quartz plate used in said step (2) has a surface polished to have a clean and smooth surface.

6. A thick cesium lead halide perovskite film produced by the production method according to any one of claims 1 to 5.

7. The cesium lead halogen perovskite thick film of claim 6, wherein the surface roughness of the cesium lead halogen perovskite thick film is less than 100nm and the grains are greater than 50 um.

8. The cesium lead halogen perovskite thick film of claim 6, wherein the area of the cesium lead halogen perovskite thick film is not less than 2.5cm x 2.5 cm.

9. Use of a thick cesium lead halide perovskite film as claimed in any one of claims 6 to 8 in radiation detection.

Technical Field

The invention belongs to the technical field of radiation detection prepared from semiconductor materials, and particularly relates to a cesium-lead halogen perovskite thick film, and preparation and application thereof, wherein the quasi-single-crystal cesium-lead halogen perovskite thick film prepared by the preparation method can be particularly applied to a radiation detector as a functional material.

Background

Radiation imaging detectors are widely used in medical health, public safety, high-end manufacturing industries and other industries. Detectors for detecting radioactive rays are generally of the type gas detectors, scintillation detectors, semiconductor detectors, etc., wherein the best energy resolution is obtained by the semiconductor detectors. Since X-rays have a refractive index of 1, which makes it difficult to focus X-rays, a large-area thick semiconductor film matching the imaging size is required.

In recent years, a series of advances are made in the field of X-ray detection due to the advantages of high X-ray absorption coefficient, high carrier collection efficiency and the like of organic-inorganic hybrid lead-based perovskite semiconductors (Nature 550, 87-91,2017; Nat. photon11,436,2017), high-sensitivity X-ray detection is realized, but the stability of the material is reduced due to the existence of organic ions, and the stability of the material is improved due to the fact that the cesium ions are replaced by the discovered cesium ions for cesium lead halogen calcium titanium ore. However, the process for preparing the thick cesium-lead halogen perovskite film has the problems of insufficient thickness, too small crystal grains, inconsistent orientation and the like, and the application of the cesium-lead halogen perovskite in the radiation imaging field is limited.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention aims to provide a cesium-lead halogen perovskite thick film and preparation and application thereof, wherein the overall process flow design (including a temperature control program) of the preparation method is improved, so that the quasi-single crystal cesium-lead halogen perovskite thick film with high performance, consistent orientation, stability, high sensitivity and large area can be obtained, and the problems of complex process, low sensitivity, inconsistent orientation and the like in the prior art are solved. The prepared cesium-lead halogen perovskite has large-size crystal grains (with quasi-single crystal characteristics) which are penetrated up and down and consistent orientation, and ensures efficient transmission of current carriers during radiation detection application of the thick film.

To achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a thick cesium lead halide perovskite film, comprising the steps of:

(1) placing the cesium-lead halogen perovskite material on a substrate, and then heating to raise the temperature to be higher than the melting point of the cesium-lead halogen perovskite until the cesium-lead halogen perovskite is completely melted into a liquid state;

(2) keeping the temperature above the melting point of the cesium-lead halogen perovskite, covering a quartz plate on a liquid perovskite material, and uniformly dispersing the liquid perovskite material covered by the quartz plate on the substrate;

(3) and slowly reducing the temperature at the speed of 0.1-5 ℃/min for cooling, then removing the quartz plate, and obtaining a perovskite thick film adhered on the substrate by using the inertia between the quartz plate and the cesium lead halogen perovskite, wherein the perovskite thick film is the cesium lead halogen perovskite thick film with the thickness of not less than 1 um.

According to another aspect of the present invention, there is provided a method for preparing a thick cesium lead halide perovskite film, comprising the steps of:

(1) placing cesium-lead halogen perovskite materials on a quartz plate with a groove, heating to enable the temperature to rise to be higher than the melting point of the cesium-lead halogen perovskite until the cesium-lead halogen perovskite is completely melted into a liquid state, and completely filling the groove of the quartz plate with the liquid perovskite materials;

(2) keeping the temperature above the melting point of the cesium-lead halogen perovskite, covering the substrate on the liquid perovskite material, and uniformly dispersing the liquid perovskite material in a groove space formed by surrounding the substrate and the quartz plate;

(3) and slowly reducing the temperature at the speed of 0.1-5 ℃/min for cooling, then taking down the quartz plate, and obtaining the perovskite thick film adhered on the substrate by using the inertia between the quartz plate and the cesium lead halogen perovskite, wherein the perovskite thick film is the cesium lead halogen perovskite thick film with the thickness of not less than 1 um.

As a further preferred aspect of the present invention, in the step (1), the cesium lead halogen perovskite is cesium lead iodide CsPbI₃Cesium lead bromide CsPbBr₃Cesium lead chloride CsPbCl₃Or cesium lead iodide bromide CsPbI_xBr_(3-x)(ii) a The cesium lead iodide bromide CsPbI_xBr_(3-x)Middle, 0<x<3。

As a further preferable aspect of the present invention, the substrate is an FTO transparent conductive glass substrate, or a boron nitride substrate.

As a further preferable aspect of the present invention, the surface of the quartz plate used in the step (2) is polished to have a clean and smooth surface.

According to another aspect of the present invention, the present invention provides a thick cesium lead halide perovskite film prepared by the above preparation method.

As a further preferred aspect of the present invention, the surface roughness of the thick cesium lead halogen perovskite film is less than 100nm, and the crystal grain is greater than 50 um.

As a further preferred aspect of the present invention, the area of the thick cesium lead halide perovskite film is not less than 2.5cm × 2.5 cm.

According to a further aspect of the invention, the invention provides the use of a thick cesium lead halide perovskite film as described above in radiation detection.

Compared with the prior art, the technical scheme of the invention has the advantages that the overall process flow design of the preparation method is controlled, the thickness of the film can be changed by changing the quality of the raw material cesium-lead halogen perovskite material (such as cesium-lead halogen perovskite powder), and the solvent is prevented from being used by melting, shaping and solidifying, so that air holes caused in the solvent volatilization process are avoided. Finally, a flat surface is obtained by applying a quartz plate of inert material. The cesium-lead halogen perovskite prepared by the method has large-size crystal grains penetrating up and down and consistent orientation, and ensures efficient transmission of current carriers during radiation detection application of the thick film.

Multi-selection MAPbI for perovskite radiation detection₃When organic and inorganic hybrid perovskite is adopted, the thick film is mostly prepared by a solution method, so that the problem of pores caused by solvent volatilization exists in the preparation of the thick film, and CsPbBr is used₃The represented cesium-lead halogen perovskite is mainly used for high-energy gamma radiation detection in the growth crystal test, and CsPbBr is utilized in the invention₃Has the characteristic of melting point, is matched with an inert quartz plate, and uses CsPbBr₃The melting recrystallization shaping method avoids the use of solvent, prepares a thick film with large area (the area is especially not less than 2.5cm multiplied by 2.5cm, even can reach 20cm multiplied by 20cm), and the obtained thick film can be further used for radiation detection.

According to the invention, the quartz plate is used as an inert material, and the adhesion between the quartz plate and the thick film of the perovskite can be avoided by utilizing the inertia between the quartz plate and the cesium-lead halogen perovskite. And other materials, such as mica, BN, graphite, etc., with CsPbBr₃The typical cesium lead halogen perovskites have adhesion to each other and do not exhibit inertness, and therefore cannot be used.

By using the method, the thick cesium-lead halogen perovskite film with the thickness of more than 1um, particularly the thick cesium-lead halogen perovskite film with the thickness of more than 50um can be obtained under the condition of ensuring sufficient raw materials, and the thick cesium-lead halogen perovskite film also has the characteristics of roughness of less than 100nm, crystal grains of more than 50um and consistent orientation, and particularly has a great application prospect in the field of radiation detection.

Drawings

Fig. 1 is a surface atomic force microscope for preparing a thick film according to the present invention, thereby obtaining surface roughness.

Fig. 2 is a schematic view of a cross-sectional scanning electron microscope for making thick films according to the present invention.

Figure 3 is an X-ray diffraction of thick films made according to the present invention.

Fig. 4 is an X-ray detection IT curve of a radiation detector made in accordance with the present invention.

Figure 5 is a plot of photocurrent at different voltages for a radiation detector made in accordance with the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The preparation method of the cesium-lead halogen perovskite thick film comprises the steps of uniformly dispersing a cesium-lead halogen perovskite raw material on a substrate, heating the substrate to a temperature above the melting point of perovskite, covering a clean and smooth quartz plate on the perovskite after the perovskite is completely melted, cooling the whole body, and slightly taking away the quartz plate to obtain the cesium-lead halogen perovskite thick film.

The following are specific examples: