Perovskite X-ray area array detector and preparation method thereof

Abstract

According to the perovskite X-ray area array detector and the preparation method, the perovskite X-ray area array detector comprises the top electrode, the crystalline perovskite layer, the amorphous perovskite layer and the circuit board which are sequentially arranged from top to bottom, and the amorphous perovskite layer is arranged between the crystalline perovskite layer and the circuit board, so that stress from the outside or the inside can be effectively absorbed and dispersed; in addition, the amorphous perovskite has good carrier mobility, carriers are allowed to be effectively transmitted in the amorphous perovskite, and the negative effect that charge transmission is damaged does not exist. Besides, the amorphous perovskite has relatively large ion migration activation energy, so that good stability is shown, the defects of the prior art are overcome, the sensitivity and the spatial resolution of the perovskite X-ray area array detector are greatly improved, and the imaging quality is remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of X-ray detection technology, and in particular to a perovskite X-ray array detector and a preparation method thereof. Background Art

[0002] X-ray array detectors are the core components of digital X-ray imaging systems and have wide application value in health care, industrial non-destructive testing, security testing, etc. According to the working principle of the device, X-ray detection technology is divided into indirect and direct types. Among them, indirect X-ray detectors cause serious pixel crosstalk problems due to the light scattering of scintillators, which reduces the device sensitivity and spatial resolution. In contrast, direct X-ray detectors have the advantages of high sensitivity and high spatial resolution. Therefore, direct X-ray detectors are an efficient and reliable solution to improve the quality of X-ray imaging. Perovskite has become a highly competitive semiconductor material for direct X-ray detectors due to its high X-ray absorption capacity, excellent charge transport phenomenon, and circuit-compatible large-area preparation methods. It is recognized as the next generation of X-ray detection technology in academia and industry. However, the performance of the perovskite X-ray array detector obtained by the current research is far from the theoretical prediction. The obtained image is blurred and the details are difficult to distinguish. This is mainly because the thermal expansion coefficient between perovskite and TFT or CMOS circuit boards is quite different, which leads to the generation and accumulation of interface stress, further causing random generation of interface defects and fracture of the active layer, which ultimately leads to uneven imaging and impaired charge collection.

[0003] like Figure 1 As shown in the figure, the thermal expansion coefficient between the perovskite and the TFT or CMOS circuit board in the prior art is relatively large, resulting in stress mismatch between the perovskite and the circuit board. This will increase serious interface defects, thereby causing damage to charge collection and further deteriorating the imaging quality of the perovskite X-ray array detector. Although a high-viscosity polymer layer is inserted between the perovskite layer and the pixel circuit to effectively buffer stress and promote electrical connection, due to the poor conductivity of the polymer, an overly thick gradual layer will hinder carrier transport, thereby rapidly deteriorating the performance of the X-ray detector. Therefore, this strategy still has limitations in the preparation of high-performance perovskite X-ray array detectors. Summary of the invention

[0004] In view of this, it is necessary to provide a high-performance perovskite X-ray array detector and a preparation method thereof to address the technical defects of the current perovskite X-ray array detector, which has the need to improve the detection performance.

[0005] To solve the above problems, this application adopts the following technical solutions:

[0006] One of the purposes of the present application is to provide a perovskite X-ray array detector, comprising a top electrode, a crystalline perovskite layer, an amorphous perovskite layer and a circuit board arranged in sequence from top to bottom.

[0007] In some of the embodiments, the amorphous perovskite layer contains all perovskite materials with long-range disordered structures, and the perovskite material includes amorphous iodine bismuth methyl triphenyl phosphine or amorphous SrTiO3.

[0008] In some embodiments, the crystalline perovskite layer comprises at least one of an inorganic perovskite or an organic inorganic perovskite or a halide perovskite or a complex cation perovskite or a complex halogen perovskite, the crystalline perovskite layer comprises at least one of an inorganic perovskite or an organic inorganic perovskite or a halide perovskite or a complex cation perovskite or a complex halogen perovskite, the crystalline perovskite layer comprises CsPbBr3 or MAPbBr3 or Cs x MA 1-x PbBr3, the MA is CH3NH3.

[0009] In some embodiments, the crystalline perovskite layer is a polycrystalline film or a single crystal.

[0010] In some embodiments, the top electrode comprises one of a metal electrode, a semiconductor electrode, a carbon material electrode, or a composite material electrode.

[0011] In some of the embodiments, the circuit board is a TFT circuit board or a CMOS circuit board or a conductive glass or silicon wafer.

[0012] The second object of the present application is to provide a method for preparing the perovskite X-ray array detector, comprising the following steps:

[0013] forming an amorphous perovskite layer on the upper surface of the circuit board;

[0014] forming a crystalline perovskite layer on the upper surface of the amorphous perovskite layer;

[0015] A top electrode is formed on the upper surface of the crystalline perovskite layer.

[0016] In some embodiments, the step of forming an amorphous perovskite layer on the upper surface of the circuit board further includes the following steps:

[0017] After the perovskite material is heated and melted, bubbles are removed in a vacuum environment, and then heated and melted again to form an ionic liquid;

[0018] Add the ionic liquid dropwise onto the upper surface of the circuit board and distribute it evenly;

[0019] The ionic liquid is cooled on the upper surface of the circuit board to form the amorphous perovskite layer.

[0020] In some embodiments, the step of forming a crystalline perovskite layer on the upper surface of the amorphous perovskite layer specifically includes the following steps:

[0021] preparing a crystalline perovskite layer raw material into a slurry;

[0022] Transferring the slurry onto the amorphous perovskite layer and distributing it evenly;

[0023] The slurry is annealed to form the crystalline perovskite layer.

[0024] In some embodiments, the step of forming a top electrode on the upper surface of the crystalline perovskite layer specifically includes the following steps:

[0025] An electrode is evaporated on the upper surface of the crystalline perovskite layer to form the top electrode.

[0026] This application adopts the above technical solution, and its beneficial effects are as follows:

[0027] The perovskite X-ray array detector and preparation method provided by the present application include a top electrode, a crystalline perovskite layer, an amorphous perovskite layer and a circuit board arranged in sequence from top to bottom. The present application arranges an amorphous perovskite layer between the crystalline perovskite layer and the circuit board, which can not only effectively absorb and disperse stress from the outside or inside, and play a role in buffering stress, but also the amorphous perovskite has good carrier mobility, allowing carriers to be effectively transmitted inside it, without the negative impact of impaired charge transmission. In addition, amorphous perovskite has a large ion migration activation energy, thereby showing good stability, overcoming previous technical defects, greatly improving the sensitivity and spatial resolution of the perovskite X-ray array detector, and significantly improving the imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 Schematic diagram of the principle of the stress mismatch problem faced by perovskite X-ray detectors provided by existing technology.

[0030] Figure 2 It is a schematic diagram of the structure of the perovskite X-ray array detector provided in Example 1 of the present invention.

[0031] Figure 3It is a flow chart of the steps of the method for preparing the perovskite X-ray array detector provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0032] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0033] In the description of the present application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0036] Example 1

[0037] See also Figure 2 , is a schematic diagram of the structure of the perovskite X-ray array detector provided in an embodiment of the present application, including a top electrode 110, a crystalline perovskite layer 120, an amorphous perovskite layer 130 and a circuit board 140 arranged in sequence from top to bottom. The technical solution implemented is described in detail below.

[0038] In this embodiment, the amorphous perovskite layer 130 includes all perovskite materials with a long-range disordered structure.

[0039] In some embodiments, the perovskite material includes amorphous iodine bismuth methyl triphenyl phosphine or amorphous SrTiO3.

[0040] It can be understood that the perovskite material provided in this embodiment is not limited to the above materials. The perovskite oxide with disordered crystal structure is selected, which often shows ion dislocation, defects, etc., and can effectively absorb and disperse stress from the outside or inside, and play a role in buffering stress. Moreover, the disordered amorphous perovskite has good carrier mobility, allowing carriers to be effectively transported inside it, without the negative impact of impaired charge transport. In addition, the disordered amorphous perovskite has a large ion migration activation energy, thereby showing good stability.

[0041] In this embodiment, the crystalline perovskite layer 120 comprises at least one of inorganic perovskite, organic inorganic perovskite, halide perovskite, composite cation perovskite, or composite halogen perovskite, and the crystalline perovskite layer comprises CsPbBr3, MAPbBr3, or Cs x MA 1-x PbBr3, the MA is CH3NH3.

[0042] It is understood that the crystalline perovskite layer 120 is not limited to the above materials, and generally has a crystal structure of ABX3, which is an important inorganic material. The A position is generally a monovalent alkali metal ion (such as Cs + , K + , Rb + 、Na + etc.), the B position is a divalent metal ion (such as Pb 2+ Sn 2+ ,Ge 2+ etc.), X is a monovalent halogen ion (such as I - Br - , Cl - wait).

[0043] In addition, composite cation perovskite refers to a perovskite compound containing two or more cations. The chemical structure of composite cation perovskite still maintains the general formula of perovskite ABX3, but the A position and / or B position are occupied by two or more different cations. Due to the diversity and adjustability of cations, composite cation perovskites have richer physical and chemical properties, such as adjustable optoelectronic properties, higher stability and more functional characteristics.

[0044] Furthermore, the crystalline perovskite layer 120 may be a polycrystalline film or a single crystal.

[0045] In this embodiment, the top electrode 110 includes one of a metal electrode, a semiconductor electrode, a carbon material electrode, or a composite material electrode.

[0046] In this embodiment, the circuit board 140 is a TFT circuit board or a CMOS circuit board or a conductive glass or silicon wafer.

[0047] It should be noted that: in the existing scheme, a high-viscosity polymer layer is generally inserted between the perovskite layer and the pixel circuit to effectively buffer stress and promote electrical connection. However, due to the poor conductivity of the polymer, an overly thick polymer interface layer will cause the carriers to encounter a large resistance during transmission, thereby affecting the performance of the device; and the present application sets an amorphous perovskite layer between the crystalline perovskite layer and the circuit board. Due to its amorphous structure, the amorphous perovskite layer usually has good flexibility and deformability. This characteristic enables the amorphous perovskite layer to effectively absorb and disperse stress from the outside or inside, thereby playing a role in buffering stress; secondly, amorphous perovskite has good carrier mobility, allowing carriers to be effectively transmitted inside it, and there is no negative impact of impaired charge transfer; finally, amorphous perovskite has a large ion migration activation energy and exhibits good stability, thereby greatly improving the sensitivity and spatial resolution of the perovskite X-ray array detector, and significantly improving the imaging quality.

[0048] Example 2

[0049] See also Figure 3 , which is a step flow chart of the method for preparing the perovskite X-ray array detector provided in this embodiment, includes the following steps S110 to S130, and its specific implementation scheme is described in detail below.

[0050] Step S110: forming an amorphous perovskite layer on the upper surface of the circuit board.

[0051] In this embodiment, the step of forming an amorphous perovskite layer on the upper surface of the circuit board also includes the following steps: heating and melting the perovskite material, removing bubbles in a vacuum environment, and heating and melting it again to form an ionic liquid; dripping the ionic liquid onto the upper surface of the circuit board and evenly distributing it; and cooling the ionic liquid on the upper surface of the circuit board to form the amorphous perovskite layer.

[0052] Step S120: forming a crystalline perovskite layer on the upper surface of the amorphous perovskite layer.

[0053] In this embodiment, the step of forming a crystalline perovskite layer on the upper surface of the amorphous perovskite layer specifically includes the following steps: preparing a crystalline perovskite layer raw material into a slurry; transferring the slurry onto the amorphous perovskite layer and distributing it evenly; and annealing the slurry to form the crystalline perovskite layer.

[0054] Step S130: forming a top electrode on the upper surface of the crystalline perovskite layer.

[0055] In this embodiment, the step of forming a top electrode on the upper surface of the crystalline perovskite layer specifically includes the following steps: evaporating an electrode on the upper surface of the crystalline perovskite layer to form the top electrode.

[0056] The preparation method of the perovskite X-ray array detector provided in the above embodiment of the present application is to set an amorphous perovskite layer between the crystalline perovskite layer and the circuit board. The amorphous perovskite layer usually has good flexibility and deformability due to its amorphous structure. This property enables the amorphous perovskite layer to effectively absorb and disperse stress from the outside or inside, thereby playing a role in buffering stress; secondly, the amorphous perovskite has good carrier mobility, allowing carriers to be effectively transmitted inside it without the negative impact of impaired charge transfer; finally, the amorphous perovskite has a large ion migration activation energy and exhibits good stability, thereby greatly improving the sensitivity and spatial resolution of the perovskite X-ray array detector and significantly improving the imaging quality.

[0057] The above are only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A perovskite X-ray array detector, characterized in that: It includes a top electrode, a crystalline perovskite layer, an amorphous perovskite layer and a circuit board which are arranged in sequence from top to bottom.

2. The perovskite X-ray array detector according to claim 1, characterized in that: The amorphous perovskite layer contains all perovskite materials with long-range disordered structures, and the perovskite material includes amorphous iodine bismuth methyl triphenyl phosphine or amorphous SrTiO3.

3. The perovskite X-ray array detector according to claim 1, characterized in that: The crystalline perovskite layer comprises at least one of an inorganic perovskite, an organic inorganic perovskite, a halide perovskite, a composite cation perovskite, or a composite halogen perovskite, and the crystalline perovskite layer comprises CsPbBr3 or MAPbBr3 or Cs x MA 1-x PbBr3, the MA is CH3NH3.

4. The perovskite X-ray array detector according to claim 1, characterized in that: The crystalline perovskite layer is a polycrystalline film or a single crystal.

5. The perovskite X-ray array detector according to claim 1, characterized in that: The top electrode comprises one of a metal electrode, a semiconductor electrode, a carbon material electrode, or a composite material electrode.

6. The perovskite X-ray array detector according to claim 1, characterized in that: The circuit board is a TFT circuit board or a CMOS circuit board or a conductive glass or silicon wafer.

7. A method for preparing a perovskite X-ray array detector as claimed in claim 1, characterized in that: The steps include: forming an amorphous perovskite layer on the upper surface of the circuit board; forming a crystalline perovskite layer on the upper surface of the amorphous perovskite layer; A top electrode is formed on the upper surface of the crystalline perovskite layer.

8. The method for preparing the perovskite X-ray array detector according to claim 7, characterized in that: The step of forming an amorphous perovskite layer on the upper surface of the circuit board also includes the following steps: After the perovskite material is heated and melted, bubbles are removed in a vacuum environment, and then heated and melted again to form an ionic liquid; Add the ionic liquid dropwise onto the upper surface of the circuit board and distribute it evenly; The ionic liquid is cooled on the upper surface of the circuit board to form the amorphous perovskite layer.

9. The method for preparing the perovskite X-ray array detector according to claim 7, characterized in that: The step of forming a crystalline perovskite layer on the upper surface of the amorphous perovskite layer specifically includes the following steps: preparing a crystalline perovskite layer raw material into a slurry; Transferring the slurry onto the amorphous perovskite layer and distributing it evenly; The slurry is annealed to form the crystalline perovskite layer.

10. The method for preparing the perovskite X-ray array detector according to claim 7, characterized in that: The step of forming a top electrode on the upper surface of the crystalline perovskite layer specifically includes the following steps: An electrode is evaporated on the upper surface of the crystalline perovskite layer to form the top electrode.

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