CN115988888A - Perovskite-based coaxial fibrous X-ray detector and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of X-ray detectors, in particular to a perovskite-based coaxial fibrous X-ray detector and a preparation method thereof. The perovskite-based coaxial fibrous X-ray detector sequentially comprises a metal conductive fiber, an electron transport layer, a lead-based perovskite polycrystalline film, a hole transport layer and a metal electrode from inside to outside; the lead-based perovskite polycrystalline film is MAPbBr ₃ The thickness of the polycrystalline film is 50-100 mu m. The invention adopts the metal conductive fiber as the substrate to design a coaxial structure, can be bent, can be used in flexible devices,the applicability is stronger; using MAPbBr ₃ The perovskite polycrystalline film is used as a light absorption layer, the high atomic number of the material is beneficial to the efficient absorption of X rays, the carrier mobility is high, the photoresponse is fast, and the sensitivity of the device is high. After being integrated, a plurality of fibrous X-ray detectors can also form plane imaging, and the operability is strong.

Description

Perovskite-based coaxial fibrous X-ray detector and preparation method thereof

Technical Field

The invention relates to the technical field of X-ray detectors, in particular to a perovskite-based coaxial fibrous X-ray detector and a preparation method thereof.

Background

In radiation detection, different human tissues and materials absorb X-rays to different degrees. For a direct detector, when X-rays are radiated to a direct detection material, electron-hole pairs are generated, the electrons and the holes form current under the action of an external bias voltage electric field, then the current is integrated on a TFT (thin film transistor) panel or other reading systems to form stored charges, and the X-ray dose of each point can be known by reading the charge amount through equipment. People can diagnose some diseases invisible to naked eyes or detect the nature, size and distribution of various macroscopic or microscopic defects in the workpiece through the change and distribution of the X-ray intensity. The conventional CdTe/CZT detector is applied to CT imaging through a splicing method, but has no advantages in large area and fast imaging, and cannot be used for flat detection imaging of digital radiation imaging. Other conventional materials such as alpha-Se, hgI ₂ ,PbI ₂ And the like have various problems such as large leakage current and many defects.

High resolution scintillation imaging screens or direct conversion detectors based on metal halide perovskites are promising candidates for such applications due to their heavy atom composition (e.g., pb ²⁺ 、Bi ³⁺ ，I ^- ) Having a high absorption cross section for X-rays; in addition, the materials can be processed by solution at low temperature, and have the advantages of adjustable band gap, nearly uniform photoluminescence quantum yield, low trap density, high carrier mobility, rapid optical response and the like.

At present, most of high-performance perovskite X-ray detectors are made of single crystal materials, and although the perovskite single crystal-based X-ray detectors have good X-ray response performance, the preparation of large single crystals and the processing of wafers thereof are challenging due to the fragile characteristic of single crystals, and large-area rapid imaging cannot be achieved. Therefore, from the practical application point of view, the preparation of high-performance perovskite polycrystal (thick film) is expected to provide a key material base for X-ray large-area rapid imaging. A fibrous X-ray detector based on the perovskite polycrystalline film is also rarely reported, and has great innovative significance.

Disclosure of Invention

In order to overcome the technical problems, the invention provides a perovskite-based coaxial fibrous X-ray detector and a preparation method thereof, and MAPbBr is adopted ₃ The perovskite polycrystalline film is a light absorption layer, and can meet the requirement of high sensitivity.

The invention provides a perovskite-based coaxial fibrous X-ray detector which sequentially comprises a metal conductive fiber, an electron transport layer, a lead-based perovskite polycrystalline film, a hole transport layer and a metal electrode from inside to outside; the lead-based perovskite polycrystalline film is MAPbBr ₃ The thickness of the polycrystalline film is 50-100 mu m.

Preferably, the metal conductive fiber is a titanium wire with the purity of 99%.

Preferably, the material of the electron transport layer is titanium dioxide.

Preferably, the material of the hole transport layer is poly [ bis (4-phenyl) (2, 4, 6-trimethylphenyl) amine ].

Preferably, the metal electrode is a gold electrode.

The invention also provides a preparation method of the perovskite-based coaxial fibrous X-ray detector, which comprises the following steps:

s1, preparing the electron transport layer on the surface of the conductive metal fiber;

s2, obtaining the MAPbBr on the electron transport layer by a direct electrifying heating and dropping coating method ₃ A polycrystalline thin film;

s3, in the MAPbBr ₃ The hole transport film is prepared on the polycrystalline film by dip coating and re-annealingConveying a layer;

and S4, preparing the metal electrode on the hole transport layer in a manner of sputtering by using a metal spraying instrument.

Preferably, the step S2 specifically includes:

weighing MABr and PbBr according to a molar ratio of 1 ₂ Dissolving the mixed precursor solution in an organic solvent filtered by a filter head to obtain a mixed precursor solution stock solution;

stirring the mixed precursor solution stock solution at the temperature of 60 ℃ for 1-2h until the mixed precursor solution is fully dissolved to obtain a clear and transparent mixed precursor solution;

electrifying and heating the metal conductive fiber by using a direct-current power supply, and directly dripping the mixed precursor solution on the surface of the electron transport layer;

in order to avoid solvent residue, the device is dried in vacuum for about 10-15min and then annealed for 1h at 100 ℃ to obtain MAPbBr ₃ A polycrystalline thin film.

Preferably, the direct current power supply is keithley2400, and the electrifying current is 0.3A-0.36A.

Preferably, the organic solvent is N, N-dimethylformamide.

Preferably, when the metal conductive fiber is a titanium wire with a purity of 99%, and the material of the electron transport layer is titanium dioxide, the step S1 specifically includes:

and putting the conductive metal fiber into a muffle furnace, and preparing the electron transport layer in a heating mode.

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

the perovskite-based coaxial fibrous X-ray detector adopts the metal conductive fiber as the substrate to be designed into a coaxial structure, can be bent, can be used in flexible devices, and has stronger applicability; using MAPbBr ₃ The perovskite polycrystalline film is used as a light absorption layer, the high atomic number of the material is beneficial to the efficient absorption of X rays, the carrier mobility is high, the photoresponse is fast, and the sensitivity of the device is high. After being integrated, a plurality of fibrous X-ray detectors can also form plane imaging, and the operability is strong.

Perovskite-based coaxiality of the present inventionThe preparation method of the fibrous X-ray detector has simple process steps, cheap raw materials and MAPbBr ₃ The perovskite polycrystalline film can be prepared in a large scale by the solvent volatilization principle, and is simple and efficient.

Drawings

FIG. 1 is a schematic structural view of a perovskite-based coaxial fiber X-ray detector of the present invention;

FIG. 2 is an SEM image of a MAPbBr3 polycrystalline thin film prepared in step S2 of example 1 of the present invention;

FIG. 3 is an XRD pattern of a MAPbBr3 polycrystalline thin film prepared in step S2 of example 1 of the present invention;

FIG. 4 is a graph of X-ray response of a perovskite-based coaxial fiber X-ray detector prepared in example 1 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. The following is a description of the preferred embodiments of the present invention, and it should be noted that, for those skilled in the art, various modifications and embellishments can be made without departing from the principle of the embodiments of the present invention, and these modifications and embellishments are also regarded as the scope of the present invention.

As shown in fig. 1, the invention provides a perovskite-based coaxial fibrous X-ray detector, which sequentially comprises a metal conductive fiber, an electron transport layer, a lead-based perovskite polycrystalline thin film, a hole transport layer and a metal electrode from inside to outside; the lead-based perovskite polycrystalline film is MAPbBr ₃ The thickness of the polycrystalline film is 50-100 mu m.

The metal conductive fiber is preferably a titanium wire with the purity of 99% (a thin oxide layer is attached to the surface), the electron transport layer is preferably titanium dioxide, the hole transport layer is preferably poly [ bis (4-phenyl) (2, 4, 6-trimethylphenyl) amine ], and the metal electrode is preferably a gold electrode.

The invention also provides a preparation method of the perovskite-based coaxial fibrous X-ray detector, which comprises the following steps:

s1, preparing the electron transport layer on the surface of the conductive metal fiber;

s2, obtaining the MAPbBr on the electron transport layer by a direct electrifying heating and dropping coating method ₃ A polycrystalline thin film;

s3, in the MAPbBr ₃ Preparing the hole transport layer on the polycrystalline film in a dip-coating and annealing mode;

and S4, preparing the metal electrode on the hole transport layer in a manner of sputtering by using a metal spraying instrument.

Wherein, the step S2 specifically comprises:

weighing MABr and PbBr according to a molar ratio of 1 ₂ Dissolving the mixed precursor solution in an organic solvent filtered by a filter head to obtain a mixed precursor solution stock solution;

stirring the mixed precursor solution stock solution at the temperature of 60 ℃ for 1-2h until the mixed precursor solution is fully dissolved to obtain a clear and transparent mixed precursor solution;

electrifying and heating the metal conductive fiber by using a direct-current power supply, and directly dripping the mixed precursor solution on the surface of the electron transport layer;

in order to avoid solvent residue, the device is dried in vacuum for about 10-15min and then annealed at 100 ℃ for 1h to obtain the MAPbBr ₃ A polycrystalline thin film.

The direct current power supply is keithley2400, and the current is preferably 0.3-0.36A. The organic solvent is preferably N, N-dimethylformamide.

When the metal conductive fiber is a titanium wire with the purity of 99% and the material of the electron transmission layer is titanium dioxide, the step S1 specifically comprises the following steps:

and putting the conductive metal fiber into a muffle furnace, and preparing the electron transport layer in a heating mode.

Example 1

The perovskite-based coaxial fibrous X-ray detector is prepared by the following steps:

s1: sequentially cleaning a metal titanium wire with the thickness of about 100 mu m by using deionized water, acetone and ethanol, and finally performing ultrasonic treatment in water for 10min;

and (3) putting the treated metal titanium wire into a muffle furnace, heating to 650 ℃, keeping for 30s, and then quickly taking out, wherein the titanium wire is blue, namely, a layer of titanium dioxide is covered on the titanium wire to be used as an electron transport layer.

S2: according to the mol ratio of 1:1 weighing raw materials MABr and PbBr ₂ Dissolving the mixed solution in filtered N, N-dimethylformamide to obtain a mixed precursor solution stock solution;

stirring the stock solution at the temperature of 60 ℃ for 1h until the stock solution is fully dissolved to obtain a clear and transparent precursor solution (the concentration is 1 mol/L);

electrifying and heating the titanium wire by using a keithley2400 direct current power supply (the current is about 0.3A), and directly dripping the mixed precursor solution on the surface of the titanium dioxide;

transferring the mixture into a vacuum oven for vacuumizing, pumping away residual organic solvent N, N-dimethylformamide, and then annealing the mixture for 1 hour at 100 ℃ to obtain MAPbBr with the thickness of about 80 mu m ₃ A polycrystalline thin film.

S3: will produce MAPbBr ₃ Titanium wire dip coating of polycrystalline films onto poly [ bis (4-phenyl) (2, 4, 6-trimethylphenyl) amine]Then, annealing is performed at a temperature of 100 ℃ for 30min to prepare a hole transport layer.

S4: and preparing a gold electrode on the hole transport layer by sputtering with a gold spraying instrument.

FIG. 2 shows MAPbBr prepared in step S2 of this example ₃ In the SEM image of the polycrystalline film, it can be seen that the grain growth size is large, the interconnection is tight, and the number of defects is small.

FIG. 3 shows MAPbBr prepared in step S2 of this example ₃ XRD pattern of polycrystalline film, from which it can be seen that the position of each peak is associated with MAPbBr ₃ And (4) completely inosculating.

Fig. 4 is an X-ray response performance diagram of the perovskite-based coaxial fiber X-ray detector prepared in this embodiment, and it can be seen from the diagram that the device has better stability and response capability under the continuous action of X-rays.

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

the perovskite-based coaxial fibrous X-ray detector adopts metal conductive fibers as a substrate and is designed intoThe coaxial structure can be bent, can be used in a flexible device and has stronger applicability; using MAPbBr ₃ The perovskite polycrystalline film is used as a light absorption layer, the high atomic number of the material is beneficial to the efficient absorption of X rays, the carrier mobility is high, the photoresponse is fast, and the sensitivity of the device is high. After the plurality of fibrous X-ray detectors are integrated, plane imaging can be formed, and operability is high.

The preparation method of the perovskite-based coaxial fibrous X-ray detector has the advantages of simple process steps, cheap raw materials and MAPbBr ₃ The perovskite polycrystalline film can be prepared in a large scale by the solvent volatilization principle, and is simple and efficient.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A perovskite-based coaxial fibrous X-ray detector is characterized by sequentially comprising a metal conductive fiber, an electron transport layer, a lead-based perovskite polycrystalline film, a hole transport layer and a metal electrode from inside to outside; the lead-based perovskite polycrystalline film is MAPbBr ₃ The thickness of the polycrystalline film is 50-100 mu m.

2. The perovskite-based coaxial fibrous X-ray detector of claim 1, wherein the metallic conductive fibers are titanium wires having a purity of 99%.

3. The perovskite-based coaxial fibrous X-ray detector of claim 1, wherein the electron transport layer is titanium dioxide.

4. The perovskite-based coaxial fibrous X-ray detector of claim 1, wherein the hole transport layer is poly [ bis (4-phenyl) (2, 4, 6-trimethylphenyl) amine ].

5. The perovskite-based coaxial fibrous X-ray detector of claim 1, wherein the metal electrode is a gold electrode.

6. Method for producing a perovskite-based coaxial fibrous X-ray detector according to any of the claims 1 to 5, comprising the steps of:

s1, preparing the electron transport layer on the surface of the conductive metal fiber;

s2, obtaining the MAPbBr on the electron transport layer by a direct electrifying heating and dropping coating method ₃ A polycrystalline thin film;

s3, in the MAPbBr ₃ Preparing the hole transport layer on the polycrystalline film in a dip-coating and annealing mode;

and S4, preparing the metal electrode on the hole transport layer in a manner of sputtering by using a metal spraying instrument.

7. The method for preparing a perovskite-based coaxial fibrous X-ray detector according to claim 6, wherein the step S2 is specifically:

weighing MABr and PbBr according to a molar ratio of 1 ₂ Dissolving the mixed precursor solution in an organic solvent filtered by a filter head to obtain a mixed precursor solution stock solution;

stirring the mixed precursor solution stock solution at the temperature of 60 ℃ for 1-2h until the mixed precursor solution is fully dissolved to obtain a clear and transparent mixed precursor solution;

electrifying and heating the metal conductive fiber by using a direct-current power supply, and directly dripping the mixed precursor solution on the surface of the electron transport layer;

in order to avoid solvent residue, the device is dried in vacuum for about 10-15min and then annealed at 100 ℃ for 1h to obtain the MAPbBr ₃ Polycrystalline filmAnd (3) a membrane.

8. The method of claim 7, wherein the dc power source is keithley2400 and the current is 0.3A-0.36A.

9. The method of preparing a perovskite-based coaxial fibrous X-ray detector as claimed in claim 7, wherein the organic solvent is N, N-dimethylformamide.

10. The method according to claim 6, wherein the metallic conductive fiber is a titanium wire with a purity of 99%, and when the electron transport layer is made of titanium dioxide, the step S1 is specifically as follows:

and putting the conductive metal fiber into a muffle furnace, and preparing the electron transport layer in a heating mode.

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