CN110400813A - An X-ray digital image detector based on perovskite material - Google Patents

Abstract

The invention discloses an X-ray digital image detector based on a perovskite material and a preparation method thereof, wherein the X-ray digital detector includes a scintillation layer arranged on a detection unit, and the scintillation layer material is Pb or Inorganic perovskite materials of Au. The present invention replaces the CsI material that is easy to absorb moisture and deliquescence in the scintillation layer or the GOS material that is easy to form the light expansion phenomenon into an inorganic perovskite material containing Pb or Au, so that the production process is simpler, the production cost is lower, and the environment is environmentally friendly. , equipment requirements are lower, and a composite film with better water resistance is used as a waterproof layer, so that the X-ray digital image detector will not affect the image resolution due to moisture in the air; and the inorganic calcium containing Pb or Au The titanium ore material has a strong absorption of X-rays, which improves the conversion efficiency of X-rays, thereby improving the luminous efficiency of the scintillation layer, thereby improving image quality.

Description

An X-ray digital image detector based on perovskite material

technical field

The invention relates to the field of photodetectors, in particular to an X-ray digital image detector based on a perovskite material.

Background technique

since Since the discovery of X-rays in 1985, X-rays have played an important role in many fields such as medicine, biology, material science, industry and safety inspection.

The X-ray detector is a key component of the X-ray machine, and the commonly used X-ray detector is an indirect flat panel detector (Flat Panel Detector, FPD). The X-ray detector mainly includes a substrate, a plurality of detection units arranged on the substrate, and a scintillation layer arranged on the detection units, and each detection unit is composed of a thin film transistor (TFT) and a photosensitive layer. The principle of the X-ray detector is that after the scintillation layer is irradiated by X-rays, the X-ray photons will be converted into visible light, and then the photosensitive layer will convert the visible light into an image electrical signal, and then the electrical signal will be collected by a thin-film transistor (TFT) with a gating function. , and obtain a digital image.

At present, the scintillation layer materials are mainly cesium iodide (CsI) and gadolinium oxysulfide (GOS). CsI materials are generally made into crystal column screens by high-temperature crystallization methods to improve resolution, but because CsI materials are hygroscopic materials, they will absorb moisture in the air and deliquesce, greatly reducing image resolution, and the existing X-ray scintillation screen package The method has low efficiency, complex operation and poor effect. The cost of GOS material is low and the conversion efficiency is high. However, due to the granular shape of GOS, the light expansion is serious, and the scintillation layer made of GOS is too thin, otherwise the resolution will be reduced.

Therefore, the prior art still needs to be improved and developed.

Contents of the invention

In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide an X-ray digital image detector based on perovskite materials, aiming to solve the problems of scintillators in existing X-ray detectors that are prone to moisture absorption and deliquescence, and are prone to light expansion. Phenomenon, which leads to the problem that the image resolution of the X-ray detector is reduced.

Technical scheme of the present invention is as follows:

An X-ray digital image detector based on a perovskite material, comprising a silicon-based substrate, several detection units arranged on the silicon-based substrate, and a scintillation layer arranged on the detection units, wherein the scintillation layer The material is an inorganic perovskite material containing Pb or Au.

In the X-ray digital image detector based on perovskite material, the scintillation layer material is one or more of CsPbBr ₃ , CsAuBr ₃ , CsPbCl ₃ , CsAuCl ₃ , CsPbI ₃ and CsAuI ₃ .

In the X-ray digital image detector based on perovskite material, the thickness of the scintillation layer is 100 μm.

In the X-ray digital image detector based on perovskite material, a waterproof layer is arranged on the scintillation layer, and a protective cover is arranged on the waterproof layer.

In the X-ray digital image detector based on perovskite material, the waterproof layer material is a composite film.

The X-ray digital image detector based on perovskite material, wherein, the composite film material is polyethylene (PE), polypropylene (PP), polystyrene, polyvinyl chloride (PVC), polyester (PET ), two or more of metal foils.

In the X-ray digital image detector based on perovskite material, a protection layer is further arranged between the detection unit and the scintillation layer, and the protection layer is an ITO thin film.

In the X-ray digital image detector based on perovskite material, the detection unit includes a thin film transistor and a photosensitive structure electrically connected to the thin film transistor.

The X-ray digital image detector based on perovskite material, wherein the photosensitive structure includes a sensing electrode, a photodiode, and a driving electrode, wherein the connecting wire material between the sensing electrode and the driving electrode can be Mo , Al, Ag, wherein the insulating material between the sensing electrode and the driving electrode can be SiN _x , SiO ₂ or PI thin film, wherein the sensing electrode and the source or drain in the thin film transistor electrical connection.

A method for preparing an X-ray digital image detector based on a perovskite material, comprising the steps of:

Several detection units are prepared on a silicon-based substrate, the detection units include a thin film transistor, a photosensitive structure electrically connected to the thin film transistor, and a protective layer arranged above the thin film transistor and the photosensitive structure, and the protective layer is A layer of ITO thin film;

preparing a layer of scintillation layer on the surface of the protective layer, the material of the scintillation layer is an inorganic perovskite material containing Pb or Au;

preparing a waterproof layer on the surface of the scintillation layer;

A protective cover plate is arranged on the surface of the waterproof layer to obtain the X-ray digital image detector based on the perovskite material.

The advantage of the present invention is: the X-ray digital image detector based on the perovskite material provided by the present invention, by changing the CsI material that is easy to absorb moisture and the GOS material with serious light expansion in the scintillation layer to the inorganic perovskite containing Pb or Au Mineral materials make the production process simpler, the production cost is lower, the requirements for equipment and the environment are lower, and the composite film with better waterproofness is used as the waterproof layer, so that the X-ray digital image detector will not be affected by the moisture in the air. and affect the image quality; and the inorganic perovskite material containing Pb or Au has a strong absorption of X-rays, which improves the conversion efficiency of X-rays, thereby improving the image quality.

Description of drawings

Fig. 1 is a schematic structural diagram of an X-ray digital image detector based on a perovskite material provided by the present invention.

FIG. 2 is a schematic structural diagram of an X-ray digital image detector based on a perovskite material provided by the present invention.

FIG. 3 is a flow chart of a preferred embodiment of a method for manufacturing an X-ray digital image detector based on a perovskite material provided by the present invention.

Detailed ways

The present invention provides an X-ray digital image detector based on a perovskite material and a preparation method thereof. In order to make the purpose, technical solution and effect of the present invention clearer and clearer, the present invention will be further described in detail below. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Please refer to Fig. 1 and Fig. 2, the present invention provides a kind of X-ray digital image detector based on perovskite material, as shown in the figure, described X-ray digital detector comprises silicon-based substrate 11, is arranged on silicon-based substrate Several detection units 10 on 11, and a scintillation layer 14 disposed on the detection units 10, wherein the material of the scintillation layer 14 is an inorganic perovskite material containing Pb or Au.

Specifically, the materials used in the scintillation layer in traditional X-ray digital image detectors are CsI and GOS. The CsI material is a hygroscopic material that absorbs moisture in the air and deliquesces, while the GOS material is a granular material whose light The expansion phenomenon is relatively serious, both of which will greatly reduce the image resolution, and the existing X-ray scintillation layer packaging method has low efficiency and complicated operation. In this embodiment, the CsI material that is easy to absorb moisture or the GOS material that is easy to form the light expansion phenomenon in the scintillation layer 14 is replaced by an inorganic perovskite material containing Pb or Au, because the inorganic perovskite can be used in a lower temperature environment It is processed from liquid, which makes its production process simpler, lower production cost, lower requirements on the environment and equipment, and uses a composite film with better waterproof performance as the waterproof layer, so that the X-ray digital image detector will not be damaged due to Moisture in the air affects the image quality; and the inorganic perovskite material containing Pb or Au has a strong absorption of X-rays, which improves the conversion efficiency of X-rays, thereby improving the luminous efficiency of the scintillation layer, and then improving image quality .

In a preferred embodiment, the material of the scintillation layer 14 is one or more of CsPbBr ₃ , CsAuBr ₃ , CsPbCl ₃ , CsAuCl ₃ , CsPbI ₃ and CsAuI ₃ , but not limited thereto. The inorganic perovskite nanocrystal scintillator containing cesium and lead atoms or cesium and gold atoms exhibits strong X-ray absorption and strong radioluminescence properties. Unlike previous scintillator materials, inorganic perovskite materials can be processed from liquids in a lower temperature environment, and their luminescent spectra can be adjusted by changing the anion components in the colloid; further, the inorganic calcium containing Pb or Au Titanium materials have a strong absorption of X-rays, which improves the conversion efficiency of X-rays, thereby improving the luminous efficiency of scintillators; these characteristics indicate that flexible and highly sensitive X-ray digital images can be manufactured using inorganic perovskite nanocrystal materials detector.

In a preferred embodiment, as shown in FIG. 2 , it includes a waterproof layer 15 disposed on the scintillation layer 14 , and a protective cover 16 disposed on the waterproof layer 15 . By preparing a waterproof layer on the scintillating layer, water in the air can be prevented from affecting the properties of the scintillating layer, thereby affecting image resolution. Preferably, the material of the waterproof layer is a transparent material. More preferably, the waterproof layer is a composite film, and the composite film material is polyethylene (PE), polypropylene (PP), polystyrene, polyvinyl chloride (PVC), polyester (PET), metal foil two or more of. The scintillation layer can be protected from damage by arranging a protective cover plate on the waterproof layer. Preferably, the protective cover is a carbon fiber plate or a plastic plate.

In a preferred implementation manner, as shown in FIG. 2 , a protective layer 29 is further provided between the detection unit 10 and the scintillation layer 14 , and the protective layer 29 is an ITO thin film. The protective layer is mainly used to protect the capacitance in the photoelectric conversion device and the metal leads in the circuit.

In a preferred implementation manner, as shown in FIG. 2 , the detection unit 10 includes a thin film transistor 12 and a photosensitive structure 13 electrically connected to the thin film transistor 12 . The thin film transistor 12 includes a gate 21, an insulating layer 25 disposed above the gate 21, an active layer 22 disposed above the insulating layer 25, a first electrode disposed above the active layer 22 24 and a second electrode 23; wherein, the first electrode 24 is a source or a drain, the second electrode 23 is connected to an external data line, and the gate 21 is used to control the turning on of the thin film transistor 12 or off; the amount of charges transmitted by the thin film transistors 12 of different detection units 10 through the second electrode 23 is proportional to the dose of X-rays at different positions, so that digital image signals of X-rays can be acquired.

Preferably, the insulating layer 25 is a PVX film; the active layer 22 is an a-Si:H film.

Preferably, as shown in FIG. 2 , the photosensitive structure 13 includes a sensing electrode 26, a photodiode 27, and a driving electrode 28, wherein the sensing electrode 26 is electrically connected to the source or drain of the thin film transistor 12 . Preferably, the driving electrodes 28 and the sensing electrodes 26 are made of indium tin oxide or metal molybdenum or aluminum, which are prepared by magnetron sputtering and solution methods. Specifically, the driving electrode 28 is used to apply a voltage to the photodiode 27 , and charge is formed in the photodiode 27 , and the charge moves and is received by the sensing electrode 26 . When the scintillation layer is irradiated by X-rays, it will convert the X-ray photons into visible light, and then the photodiode will convert the visible light into an image electrical signal, and then collect the electrical signal by a thin-film transistor (TFT) with a gate control function, and obtain a digital image image.

Further, the present invention also provides a method for preparing an X-ray digital image detector based on a perovskite material, wherein, as shown in Figure 3, the steps include:

S10. Prepare several detection units on a silicon-based substrate, the detection units include a thin film transistor, a photosensitive structure electrically connected to the thin film transistor, and a protective layer disposed above the thin film transistor and the photosensitive structure;

S20. Prepare a scintillator layer on the surface of the protective layer, and the material of the scintillator layer is an inorganic perovskite material containing Pb or Au;

S30. Prepare a waterproof layer on the surface of the scintillation layer;

S40, setting a layer of protective cover on the surface of the waterproof layer to manufacture the X-ray digital image detector based on perovskite material.

Specifically, the grid 21, the driving electrode 28 and the sensing electrode 26 are formed on the silicon base substrate by the method of measurement and control sputtering, and the target material of the magnetron sputtering is Mo or Al. A dielectric thin film is formed on the silicon-based substrate of the sensing electrode 26, and the dielectric thin film includes a-Si:H thin film and PVX thin film, and the a-Si:H thin film is the core thin film of the active layer 22 and is the source-drain electrode Conductive channel between 24; The main effect of described PVX thin film is as the insulating layer 25 between gate 21 and active layer 22, and the protective layer between source drain electrode 24 metals and active layer 22; The source and drain electrodes are prepared by magnetron sputtering on the silicon-based substrate, and a photodiode is added as a photosensitive layer on the silicon-based substrate forming a dielectric thin film; a protective layer 29 is added on the formed dielectric thin-film silicon-based substrate; Spin-coat an inorganic perovskite material containing Pb or Au on the 29 as a scintillation layer through a uniform glue process; sputter a layer of composite film on the scintillation layer as a waterproof layer; add a layer of protective cover on the waterproof layer plate, that is, the X-ray digital image detector based on the perovskite material of the present invention is produced.

In summary, the X-ray digital image detector based on the perovskite material provided by the present invention is replaced by the inorganic perovskite containing Pb or Au by replacing the CsI material which is easy to absorb moisture and deliquescence in the scintillation layer and the GOS material with serious light diffusion. Mineral materials make the production process simpler, the cost is lower, the requirements for equipment and the environment are lower, and the composite film with better waterproofness is used as the waterproof layer, so that the X-ray digital image detector will not be damaged by moisture in the air. affect the image resolution; and the inorganic perovskite material containing Pb or Au has a strong absorption of X-rays, which improves the conversion efficiency of X-rays, thereby improving the luminous efficiency of the scintillation layer, thereby improving image quality.

It should be understood that the application of the present invention is not limited to the above examples, and those skilled in the art can make improvements or transformations according to the above descriptions, and all these improvements and transformations should belong to the protection scope of the appended claims of the present invention.

Claims (8)

1. An X-ray digital image detector based on a perovskite material, comprising a silicon-based substrate, several detection units arranged on the silicon-based substrate, and a scintillation layer arranged on the detection unit, is characterized in that, The scintillation layer material is an inorganic perovskite material containing Pb or Au. 2. the X-ray digital image detector based on perovskite material according to claim 1, is characterized in that, described scintillation layer material is CsPbBr ₃ , CsAuBr ₃ , CsPbCl ₃ , CsAuCl ₃ , CsPbI ₃ and CsAuI ₃ one or more. 3 . The X-ray digital image detector based on perovskite material according to claim 1 , wherein a waterproof layer is arranged on the scintillation layer, and a protective cover is arranged on the waterproof layer. 4 . 4. according to the described X-ray digital image detector based on perovskite material of claim 3, it is characterized in that, described waterproof layer is composite film, and described composite film material is polyethylene (PE), polypropylene (PP) , polystyrene, polyvinyl chloride (PVC), polyester (PET), two or more of metal foil. 5 . The X-ray digital image detector based on perovskite material according to claim 1 , wherein a protective layer is further arranged between the detection unit and the scintillation layer, and the protective layer is an ITO thin film. 6 . The X-ray digital image detector based on perovskite material according to claim 1 , wherein the detection unit comprises a thin film transistor and a photosensitive structure electrically connected to the thin film transistor. 7. The X-ray digital image detector based on perovskite material according to claim 6, wherein the photosensitive structure comprises a sensing electrode, a photodiode and a driving electrode, wherein the sensing electrode and the thin film The source or drain electrical connection in a transistor. 8. A method for preparing an X-ray digital image detector based on a perovskite material, comprising the steps of: Several detection units are prepared on the first substrate, and the detection units include a thin film transistor, a photosensitive structure electrically connected to the thin film transistor, and a layer of ITO thin film arranged above the thin film transistor and the photosensitive structure as The protective layer; preparing a layer of scintillation layer on the surface of the protective layer, the material of the scintillation layer is an inorganic perovskite material containing Pb or Au; preparing a waterproof layer on the surface of the scintillation layer; A protective cover plate is arranged on the surface of the waterproof layer to obtain the X-ray digital image detector based on the perovskite material.