KR101839692B1 - X-ray detector having photoconductor comprising perovskite compound - Google Patents

Abstract

The present invention discloses an x-ray detector with a photoconductor comprising a perovskite compound. An X-ray detector according to an embodiment of the present invention includes a substrate; A first electrode formed on the substrate; A photoconductor layer formed on the first electrode and generating electron-hole pairs by an incident X-ray; And a second electrode formed on the photoconductor layer, wherein the photoconductor layer comprises a perovskite compound represented by the following formula (1).
[Chemical Formula 1]
A ₃ M ₂ X ₉
Wherein A is a monovalent cation, M is a trivalent metal cation, and X is a monovalent anion.

Description

X-RAY DETECTOR HAVING PHOTOCONDUCTOR COMPRISING PEROVSKITE COMPOUND INCLUDING POROUS BITE COMPOUND

The present invention relates to an x-ray detector with a photoconductor comprising a perovskite compound.

Recently, X-ray detectors are becoming an important medical device for diagnosing patients' diseases. As a result, the phase of x-ray detectors in the medical device industry is increasing day by day. Accordingly, techniques for high reliability X-ray detectors have been developed in order to accurately and quickly diagnose a patient's disease.

The x-ray detector outputs the x-ray image taken by the x-ray or the x-ray perspective image as a digital signal. Such an X-ray detector is divided into a direct method (direct conversion method) and an indirect method (indirect conversion method).

The direct method converts an X-ray directly into a charge in a photoconductor (photoconductor), an indirect method converts an X-ray into a visible light from a scintillator, and converts the converted visible light into a photoelectric conversion And is converted into electric charge through a device.

The indirect method is a method of converting an X-ray into a visible light through mutual reaction with a scintillator, which causes scattering of light, resulting in lower resolution. On the other hand, the direct method has advantages of excellent image resolution, excellent conversion efficiency and collection efficiency by detecting direct converted battery signals, and it is possible to reduce radiation (x-ray) exposure to a patient and to easily manufacture a large- have.

A direct x-ray detector includes a photoconductor layer that generates electron-hole pairs by x-ray irradiation, and a plurality of pixel electrodes formed at the bottom of the photoconductor layer and receiving charge from the photoconductor.

Photoconductor materials used in such direct x-ray detectors should have high x-ray absorbance, low leakage current, good charge collection rate, and fast signal response characteristics. These properties depend on the physical properties of the material such as atomic number, bandgap energy, efficient electron-hole generation energy (W), charge mobility and lifetime.

That is, the band gap energy of the photoconductor is advantageously larger in order to reduce the thermal leakage current, and the lower the X-ray energy required to generate the electron-hole pairs, the higher the sensitivity. Also, the charge mobility and lifetime of the photoconductor are good enough to exhibit excellent characteristics such as the collection efficiency of charge generated in the photoconductor and the time response characteristic.

To date, photoconductor materials commercialized in direct-mode x-ray detectors include amorphous selenium (a-Se) and CdTe. A typical example of this is a-Se, which can easily and quickly perform a deposition process, has a small dark current, and has a large resistivity. However, there is a disadvantage in that the electron-hole generating energy (W) is high and the operating voltage is high, so that breakdown and lifetime of the device, low sensitivity, and charge trap phenomenon occur.

In addition, photoconductor materials reported so far such as HgI ₂ , PbI ₂ , and CdZnTe are difficult to manufacture in a large area, and have limitations in electrical operation characteristics and reliability of the device.

For this reason, direct x-ray detectors are required to have thicker photoconductor layers to increase x-ray absorption. However, due to crack and uniformity in the manufacture of thick films, deterioration of the performance of the X-ray detector and an increase in the process cost due to long processing time have been caused.

 In addition, it takes a long time to mass production, and there is a drawback that it lacks the technology that can be manufactured in a reproducible manner. In order to overcome this disadvantage, it is very important to fabricate a thick, high-reproducibility photoconductor layer.

Korean Patent Laid-Open No. 10-2006-0075922, "X-ray detector and analyzing apparatus using the same" Japanese Patent No. 4683719, "Oxide phosphor and radiation detector using it and X-ray CT apparatus"

An embodiment of the present invention seeks to provide an x-ray detector having a photoconductor comprising a perovskite compound.

Also, an embodiment of the present invention is directed to providing an x-ray system comprising an x-ray detector with a photoconductor comprising a perovskite compound.

An X-ray detector according to an embodiment of the present invention includes a substrate; A first electrode formed on the substrate; A photoconductor layer formed on the first electrode and generating electron-hole pairs by an incident X-ray; And a second electrode formed on the photoconductor, wherein the photoconductor layer comprises a perovskite compound represented by the following formula (1).

[Chemical Formula 1]

A ₃ M ₂ X ₉

(In the formula 1,

A is a monovalent cation,

M is a trivalent metal cation,

X is a monovalent anion.)

And A is straight or branched chain alkyl group, a C _{1 ~ 24} amine (-NH _3), hydroxyl groups (-OH), cyano group (-CN), a halogen group, a nitro group (-NO), a methoxy group (-OCH ₃ ) or imidazolium group substituted linear or branched C _{1 ~ 24} ^{alkyl, Li +, Na +, K} +, Rb +, Cs +, Fr +, Cu (I) +, Ag (I) + and Au ( I) ⁺ . ≪ / RTI >

Wherein M is a ^{3 +} In, Bi ^{+ 3,} Co ^{+ 3,} Sb ^{+ 3,} Ni ^{+ 3,} Al ^{+ 3,} Ga ^{+ 3,} Tl ^{+ 3,} Sc ^{+ 3,} Y ^3+, La ^{+ 3,} Ce ^{+ 3} , Fe ^3+, Ru ^{+ 3,} Cr ^{+ 3,} may include at least one selected from the group consisting of V ³⁺ and Ti ^{+ 3.}

The X may include at least one selected from the group consisting of F ^- , Cl ^- , Br ^- , I ^- , SCN ^- and BF ₄ ^- .

The perovskite compound may be nanocrystalline particles.

The particle size of the nanocrystalline particles may range from 1 nm to 500 nm.

The trap density of the photoconductor layer may be between 10 ⁸ cm ^-2 and 10 ¹⁶ cm ^-2 .

The photoconductor layer may further comprise a trap healing material.

The trapping healing material may include at least one selected from the group consisting of graphene quantum dots, fullerene (C ₆₀ ), derivatives thereof, and the like.

The photoconductor layer may further comprise an organic binder.

Wherein the organic binder is selected from the group consisting of polyvinyl butyral resin, polyvinyl chloride resin, acrylic resin, phenoxy resin, polyester resin, polyvinyl formal resin, polyamide resin, polystyrene resin, polycarbonate resin, polyvinyl acetate resin, polyurethane A resin, and an epoxy resin.

The perovskite compound and the organic binder may be contained in the photoconductor layer in a weight ratio of 90:10 to 10:90.

The photoconductor further comprises an inorganic binder.

The inorganic binder may include at least one selected from the group consisting of TiO ₂ nanoparticles, SiO ₂ nanoparticles, Al ₂ O ₃ nanoparticles, VO ₂ nanoparticles, layered compounds, metal alkoxides, and metal halides.

The perovskite compound and the inorganic binder may be contained in the photoconductor layer in a weight ratio of 90:10 to 10:90.

The particle size of the inorganic binder may range from 1 nm to 100 nm.

The thickness of the photoconductor layer may range from 1 [mu] m to 1,000 [mu] m.

The first electrode may be formed of one selected from the group consisting of Al, Ag, Au, Cu, Pd, Pt, ITO, AZO, And at least one selected from the group consisting of tin oxide (FTO), carbon nanotube (CNT), graphene, and polyethylene dioxythiophene: polystyrene sulfonate (PEDOT: PSS).

The second electrode may be formed of at least one selected from the group consisting of Al, Ag, Au, Cu, Pd, Pt, ITO, AZO, And at least one selected from the group consisting of tin oxide (FTO), carbon nanotube (CNT), graphene, and polyethylene dioxythiophene: polystyrene sulfonate (PEDOT: PSS).

And an electron transport layer between the first electrode and the second electrode.

The electron transport layer may comprise a metal oxide.

And may further include a hole-transporting layer between the first electrode and the second electrode.

The hole transporting layer may include at least one selected from the group consisting of a thiophene series, a paraphenylene vinylene series, a carbazole series, and a triphenylamine series.

The substrate may comprise any one selected from the group consisting of glass, quartz, silicon, and plastic.

The substrate may be an array substrate comprising a thin film transistor (TFT), a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

An X-ray system according to an embodiment of the present invention includes an X-ray generator for generating an X-ray; An X-ray detector for detecting the X-ray; A driving unit for driving the X-ray detector; And a data processing unit for processing the X-ray detection voltage.

The x-ray system according to an embodiment of the present invention may be a diffraction analysis apparatus (XRD).

The x-ray system according to an embodiment of the present invention may be a non-destructive inspection apparatus.

According to the embodiment of the present invention, since the perovskite compound is used as the material of the photoconductor layer, the manufacturing process of the X-ray detector can be simplified and the manufacturing cost can be reduced.

Also, according to the embodiment of the present invention, the photoconductor layer can have both the advantages of the organic material and the advantages of the inorganic material, so that the thick film is easily manufactured, the reproducibility is high, and the durability is excellent.

In addition, according to the embodiment of the present invention, the perovskite compound has excellent sensitivity, light absorption characteristics, time resolution, and low resistance to X-rays due to its fast response speed.

Further, according to the embodiment of the present invention, the adhesive force with the substrate can be improved by mixing the perovskite compound and the inorganic binder having excellent adhesive strength.

In addition, according to the embodiment of the present invention, it is possible to realize a high-resolution X-ray image and moving image by implementing a direct type X-ray detector having a photoconductor layer including a perovskite compound.

1 is a cross-sectional view of an X-ray detector according to an embodiment of the present invention.
2 shows a structure of a perovskite compound represented by Chemical Formula 1 according to an embodiment of the present invention.
3 is a plan view of an X-ray detector according to an embodiment of the present invention.
FIGS. 4A through 4F are cross-sectional views of a heterojunction X-ray detector according to an embodiment of the present invention.
5 illustrates an x-ray system including an x-ray detector according to an embodiment of the present invention.
6 is an image showing an X-ray diffraction (XRD) analysis apparatus according to an embodiment of the present invention.
7 is an image showing an application field of the nondestructive inspection apparatus according to the embodiment of the present invention.
8 is an X-ray diffraction (XRD) analysis graph of a photoconductor layer comprising the perovskite compound prepared in Example 1. FIG.
9 is a scanning electron microscope (SEM) image of a photoconductor layer comprising the perovskite compound prepared in Example 1. Fig.
FIGS. 10A and 10B are graphs showing the relationship between the Cs ₃ Pb ₂ I ₉ prepared in Example 1 and Comparative Example 1 Ray detectors with a photoconductor layer comprising perovskite compound and CdTe, respectively.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and accompanying drawings, but the present invention is not limited to or limited by the embodiments.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

As used herein, the terms "embodiment," "example," "side," "example," and the like should be construed as advantageous or advantageous over any other aspect or design It does not.

Also, the term 'or' implies an inclusive or 'inclusive' rather than an exclusive or 'exclusive'. That is, unless expressly stated otherwise or clear from the context, the expression 'x uses a or b' means any of the natural inclusive permutations.

Also, the phrase "a" or "an ", as used in the specification and claims, unless the context clearly dictates otherwise, or to the singular form, .

It will also be understood that when an element such as a film, layer, region, configuration request, etc. is referred to as being "on" or "on" another element, And the like are included.

Hereinafter, an X-ray detector according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a cross-sectional view of an X-ray detector according to an embodiment of the present invention.

Referring to FIG. 1, an x-ray detector 100 includes a substrate 110, a first electrode 120, a photoconductor layer 130, and a second electrode 140.

The X-ray detector 100 according to the embodiment of the present invention may be of the Schottky type.

The substrate 110 may be an array substrate comprising a thin film transistor (TFT), a charge coupled device (CCD), or a complementary metal-oxide semiconductor (CMOS) have.

The X-ray detector 100 is widely used not only for medical use but also for industrial use. For medical use, the X-ray detector 100 is not greatly influenced by the external environment.

The CCD array substrate has a longer lifetime and excellent temperature variation as compared with the detector using another array substrate, and is advantageous for imaging the non-destructive inspection field and the fine image structure.

The CMOS array substrate is mainly used for dental and mammography (breast cancer) because it can acquire high-speed image without residual image, low power consumption, high productivity and economical efficiency, and can design a highly integrated and high resolution sensor. In addition, the CMOS array substrate can be used as a single photon counting detector in the future because it can perform high-speed high-speed processing. However, since the CMOS substrate is manufactured based on silicon (Si), it is difficult to manufacture the CMOS substrate in a large area.

The TFT array substrate can be widely used as a detector for chest and industrial because it is easy to fabricate a large area. In describing the X-ray detector 100 according to the embodiment of the present invention, a TFT array substrate is exemplarily described as the substrate 110, but the present invention is not limited thereto.

The substrate 110 may be formed of an insulating material. The substrate 110 may be formed of, for example, glass, quartz, silicon, or plastic.

For example, plastic substrates can be used in flexible or bendable x-ray detectors. In addition, the silicon substrate can be used for a bendable x-ray detector when the thickness is reduced to 100 μm or less.

A first electrode (120) is formed on the substrate (110). Specifically, the first electrode 120 may be formed on an interlayer insulating layer (not shown) formed to conformally cover the substrate 110 on which the thin film transistor (not shown) and the capacitor (not shown) are formed have.

The first electrode 120 may be a plurality of pixel electrodes. Specifically, the first electrode 120 may be formed on the substrate 110 in units of a plurality of pixels to form a pixel array constituting an X-ray image.

The first electrode 120 may be formed of a conductive material having excellent electrical characteristics.

The first electrode 120 may be formed of a metal such as aluminum (Al), silver (Ag), gold (Au), copper (Cu), palladium (Pd), platinum (Pt), indium tin oxide ), Indium Zinc Oxide (IZO), Aluminum Zinc Oxide (AZO), Fluorine Tin Oxide (FTO), Carbon Nano Tube (CNT), graphene ) And polyethylene dioxythiophene: polystyrene sulfonate (PEDOT: PSS).

A photoconductor layer 130 is formed on the first electrode 120.

The photoconductor layer 130 passes through the second electrode 140 and generates electron-hole pairs by an X-ray incident on the photoconductor layer 130. The amount of electron-hole pairs depends on the amount of energy of the x-rays absorbed in the photoconductor layer 130.

Photoconductor layer 130 includes a perovskite compound. Specifically, the photoconductor layer 130 is a material capable of absorbing X-rays incident through the second electrode 140 and converting the X-ray into an electrical signal, and has a perovskite structure, ≪ / RTI >

The photoconductor layer 130 may include a perovskite compound represented by the following formula (1).

[Chemical Formula 1]

A ₃ M ₂ X ₉

In Formula 1, A is a monovalent cation, M is a trivalent metal cation, and X is a monovalent anion.

The A may be a monovalent organic cation, a monovalent inorganic cation or a combination thereof.

Specifically, the perovskite compound may be an organic / inorganic hybrid perovskite compound or an inorganic metal halide perovskite compound according to the type of A in the formula (1) ).

More specifically, when A in the general formula (1) is a monovalent organic cation, the perovskite compound is an organic or inorganic hybrid perovskite compound composed of an organic substance A and inorganic substances M and X, Lt; / RTI > On the other hand, when A in the general formula (1) is a monovalent inorganic cation, the perovskite compound may be an inorganic metal halide perovskite compound composed of inorganic substances A, M, and X and entirely composed of inorganic substances.

In the case of organic and hybrid perovskite compounds, it is easy to manufacture into thick film due to both the advantages of organic materials and the advantage of minerals, and it is highly reproducible and improves the durability and stability of X-rays .

On the other hand, when the perovskite compound is an inorganic metal halide perovskite compound, it can be easily produced into a thick film like the organic hybrid perovskite compound and has high reproducibility. In addition, the perovskite compound of the inorganic metal halide has an advantage that the durability and the stability are higher than that of the organic hybrid perovskite because no organic material is used.

The monovalent organic cation is a linear or branched C _{1 to} C ₂₄ alkyl, an amine group (-NH ₃ ), a hydroxyl group (-OH), a cyano group (-CN), a halogen group, a nitro group (-NO) -OCH ₃ ), or straight or branched C _{1 to} C ₂₄ alkyl substituted with an imidazolium group, or combinations thereof.

The monovalent inorganic cation may be Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Fr ⁺ , Cu (I) ⁺ , Ag (I) ⁺ , Au (I) ⁺ or combinations thereof.

Wherein M is a ^{3 +} In, Bi ^{+ 3,} Co ^{+ 3,} Sb ^{+ 3,} Ni ^{+ 3,} Al ^{+ 3,} Ga ^{+ 3,} Tl ^{+ 3,} Sc ^{+ 3,} Y ^3+, La ^{+ 3,} Ce ^{+ 3 , Fe 3+, Ru 3 +,} Cr 3 +, V 3+, Ti 3 + or a combination thereof.

Wherein X is ^{F -, Cl -, Br -} , I -, SCN -, BF 4 - or a combination thereof.

The structure of the perovskite compound represented by Formula 1 will be described with reference to FIG.

2 shows a structure of a perovskite compound represented by Chemical Formula 1 according to an embodiment of the present invention.

Referring to FIG. 2, the perovskite compound represented by Formula 1 according to an embodiment of the present invention may have a hexagonal structure and may be composed of a unit cell U, For example, it may have an A ₃ M ₂ X ₉ chemical structure in which organic and inorganic materials are mixed.

Specifically, when A is Cs, M is Pb, and X is I, the perovskite compound may have a chemical structure of Cs ₃ Pb ₂ I ₉ . In addition, when X is combined with Br or Cl in addition to I, the perovskite compound is chemically bonded to Cs ₃ Pb ₂ (I _1-x Br _x ) ₉ or Cs ₃ Pb ₂ (I _1-x Cl _x ) ₉ Structure. Where x is 0 < x < 1.

The perovskite compound may be included in the photoconductor layer 130 in the form of a plurality of nanocrystalline particles (hereinafter referred to as perovskite nanocrystalline particles).

The particle size of the perovskite compound, that is, the size of the perovskite nanocrystalline particles can be in the range of 1 nm to 900 nm, and preferably in the range of 1 nm to 500 nm.

When the size of the perovskite nanocrystalline particles is less than 1 nm, the band gap changes due to the particle size, the distribution of the particle size is difficult to control, and the fine adjustment is required, which is disadvantageous to mass production .

When the size of the perovskite nanocrystalline particles exceeds 900 nm, there is a problem that the efficiency is reduced by thermal ionization at room temperature and delamination of the charge carrier. Also, it is difficult to manufacture due to the difficulty of coating, and it is not applicable to flexible X-ray detector.

The perovskite nanocrystalline particles may have a core-shell structure.

The perovskite nanocrystalline grains of a core-shell structure surround a first perovskite nanocrystal particle core and a first perovskite nanocrystalline particle core and include a shell comprising second perovskite nanocrystalline particles . Here, the first perovskite nanocrystal grains and the second perovskite nanocrystal grains may be different from each other.

The perovskite nanocrystalline particles may further comprise an organic ligand formed on the surface of the perovskite nanocrystal particle so as to surround the surface of the perovskite nanocrystalline particles.

The organic ligand may comprise an alkyl halide, and the alkyl halide may be a structure of alkyl-G. Here, the halogen element corresponding to G may include F, Cl, Br or I.

Further, the alkyl (alkyl) structure is a primary alcohol having a structure as acyclic alkyl _{(acyclic alkyl), C n H} 2n + 1 OH having the structure _{C n H 2n +1 (primary alcohol} ), secondary alcohols (secondary alcohol Tertiary alcohols, alkylamines having a structure of alkyl-N (ex. Hexadecyl amine, 9-octadecenylamine, 1-amino-9-octadecene (C ₁₉ H ₃₇ N) But are not limited to, p-substituted aniline, phenyl ammonium, or fluorine ammonium.

The trap density of the photoconductor layer 130 may be between 10 ⁸ cm ^-2 and 10 ¹⁶ cm ^-2 .

The amorphous selenium (a-Se) photoconductor layer used in the conventional direct conversion X-ray detector has a high trap density, so a high voltage must be applied in order to operate the X-ray detector. If the applied voltage is high, an unreasonable electric field is applied to the X-ray detector, and the life of the detector is reduced.

However, the photoconductor layer 130 used in the X-ray detector of the present invention can improve the drivability by reducing the trap density.

If the trap density is less than 10 ⁸ cm ^-2 , the photoconductor layer 130 is difficult to manufacture due to its material characteristics, and when it exceeds 10 ¹⁶ cm ^-2 , the photoconductor layer 130 operates with a high efficiency photoconductor layer 130 there is a problem.

The photoconductor layer 130 may further include a trap healing material.

When the photoconductor layer 130 further includes a trap healing material, the photoconductor layer 130 may have a trap density of 10 ⁷ cm ^-2 to 10 ¹⁵ cm ^-2 , have. Further, as the trap density is reduced, electrons and holes can be moved quickly without being caught by the trap, and can be implemented as a video X-ray image sensor.

The trapping healing material may comprise at least one selected from the group consisting of graphene quantum dots, fullerene (C ₆₀ ), derivatives thereof, and the like.

The particle size of the trapping healing material may range from 1 nm to 500 nm.

The photoconductor layer 130 may further comprise an organic binder.

The organic binder may be included in the photoconductor layer 130 along with the perovskite compound to improve the flexibility of the photoconductor layer 130.

Future devices are demanding flexible devices. However, conventionally used X-ray detectors are not easily bendable, and there is a problem that they are not operated due to damage of the X-ray detector at the moment of bending. Especially, in the case of a detector used in a dentistry, a flexible X-ray detector is required according to a human oral structure.

Flexible X-ray detectors can not only reduce the patient's pain but also enable high-performance images by allowing the user to take images at various angles (in the case of hard detectors, parts that can not be photographed).

The x-ray detector of the present invention includes an organic binder that can enhance solubility in the photoconductor layer 130, thereby facilitating the manufacture of a flexible x-ray detector.

The organic binder includes, for example, polyvinyl butyral resin, polyvinyl chloride resin, acrylic resin, phenoxy resin, polyester resin, polyvinyl formal resin, polyamide resin, polystyrene resin, polycarbonate resin, polyvinyl acetate resin , A polyurethane resin, an epoxy resin, or a combination thereof.

The photoconductor layer 130 may include a perovskite compound and an organic binder in a weight ratio of 90:10 to 10:90.

The photoconductor layer 130 absorbs the x-rays to generate electrons and holes. When the organic binder is contained in the photoconductor layer 130 in excess of the above-mentioned weight ratio, electrons and holes generated in the photoconductor layer The resolution and resolution are lowered, which may deteriorate the performance of the X-ray detector.

The photoconductor layer 130 may further include an inorganic binder.

The adhesion of the material of the photoconductor layer 130 to the substrate is important so that the adhesion between the photoconductor layer 130 and the substrate 110 can be improved when the photoconductor layer 130 further includes an inorganic binder .

Specifically, the inorganic binder may be included in the photoconductor layer 130 together with the perovskite compound to improve the adhesion of the photoconductor layer 130. More specifically, the photoconductor layer 130 includes an inorganic binder together with the perovskite compound, so that the adhesion between the perovskite compound and the inorganic binder is improved, and the adhesion between the substrate 110 and the photoconductor layer 130 is improved, Can be improved.

The inorganic binder may include at least one selected from the group consisting of TiO ₂ nanoparticles, SiO ₂ nanoparticles, Al ₂ O ₃ nanoparticles, VO ₂ nanoparticles, layered compounds, metal alkoxides, and metal halides.

In the photoconductor layer 130, the perovskite compound and the inorganic binder may be contained in a weight ratio of 90:10 to 10:90.

When the inorganic binder is contained in the photoconductor layer 130 in excess of the above-mentioned weight ratio, the amount of electrons and holes generated in the photoconductor layer is reduced, resulting in degraded resolution and resolution, thereby deteriorating the performance of the x- .

The particle size of the inorganic binder may range from 1 nm to 100 nm.

When the particle size of the inorganic binder is less than 1 nm, there is a problem in controlling uniform particles. When the particle size of the inorganic binder is more than 100 nm, scattering of the X-rays is made large and it is difficult to realize a high resolution image.

The photoconductor layer 130 may be formed on the substrate 110 through a solution coating method and a deposition method using a perovskite compound solution in which a perovskite compound is dissolved in a solvent.

The solution coating method includes, for example, spin coating, spray coating, ultra-spray coating, electrospin coating, slot die coating, gravure coating, A roll coating, a dip coating, a shear coating, a screen printing, an inkjet printing, or a nozzle printing, .

The deposition method may be performed by, for example, sputtering, atomic layer deposition (ALD), chemical vapor deposition (CVD), thermal evaporation, co-evaporation, or the like, at a reduced pressure, Plasma enhanced chemical vapor deposition (PECVD), and the like.

Preferably, the photoconductor layer 130 is formed by a solution process, which simplifies the manufacturing process and can reduce manufacturing costs.

The photoconductor layer 130 should be made of a thick film to absorb the high energy x-rays.

When the photoconductor layer 130 is formed of a sufficiently thick thick film, even if electrons and holes are generated by X-ray absorption, electrons or holes can not be formed as a first electrode (pixel electrode) 120 without an external applied voltage, An electric field is formed by a high applied voltage so that electrons or holes can be collected toward the first electrode (pixel electrode) 120.

The photoconductor layer 130 may be formed relatively thick with a thickness ranging from 1 [mu] m to 1,000 [mu] m.

If the thickness of the photoconductor layer 130 exceeds 1,000 占 퐉, there is a disadvantage that the photoconductor layer 130 is peeled off from the substrate 110 or adhered to the substrate 110. If the thickness of the photoconductor layer 130 is less than 1 占 퐉 , The amount of absorption of the X-ray is small and the signal is weak to the noise level.

On the other hand, as compared with the photoconductor layer of the X-ray detector according to the embodiment of the present invention, the light absorption layer of the solar cell generates electron-hole pairs by the light in the visible ray region instead of the X-ray, It moves naturally. Since the thickness of the light absorption layer of the solar cell is thin film relative to the photoconductor layer of the X-ray detector, the diffusion distance is long, so that electrons and holes can reach the electrode without trapping in the light absorption layer.

The mobility of the charge generated in the photoconductor layer 130 is very important to realize a high-resolution X-ray image and a moving image.

In the case of the direct type x-ray detector up to now, the charge generated in the photoconductor layer 130 is trapped in the trap and the speed of moving to the pixel array is slow, so that the x-ray moving image sensor can not be manufactured. Further, in order to transfer the trapped trapped charge to each pixel, a high applied voltage is required, and there is a disadvantage that image information generated in each pixel and information transferred thereafter are overlapped or a high voltage is required.

According to an embodiment of the present invention, since the photoconductor layer 130 is formed including the perovskite compound, it is possible to prevent the delay in the time that the charge generated in the photoconductor layer 130 is trapped in the trap And thus has excellent sensitivity, light absorption characteristics and time resolution for X-ray, and can have a low resistance characteristic.

A second electrode (140) is formed on the photoconductor layer (130).

The second electrode 140 may be a common electrode.

The second electrode 140 may be formed of a conductive material having excellent electrical characteristics.

The second electrode 140 may be formed of, for example, aluminum, silver, gold, copper, palladium, platinum, indium tin oxide ), Indium Zinc Oxide (IZO), Aluminum Zinc Oxide (AZO), Fluorine Tin Oxide (FTO), Carbon Nano Tube (CNT), graphene ) And polyethylene dioxythiophene: polystyrene sulfonate (PEDOT: PSS).

According to one aspect of the present invention, the second electrode 140 may be formed using the same or different materials as the first electrode 120.

Hereinafter, the structure of the second electrode 140 will be described in more detail with reference to FIG.

3 is a plan view of an X-ray detector according to an embodiment of the present invention.

3, a first electrode 120 is formed on a substrate 110, a photoconductor layer 130 is formed on the first electrode 120, a second electrode 140 is formed on the photoconductor layer 130, (130).

The first electrode 120 may have a plurality of pixel electrode structures and the second electrode 140 may have a single electrode structure that covers the first electrode 120.

According to one aspect of the present invention, the second electrode 140 may be formed to have a size equal to or smaller than the photoconductor layer 130. If the size of the second electrode 140 is larger than the size of the substrate 110, a current may flow to the side of the substrate 110 to cause a short.

Hereinafter, the operation of the X-ray detector 100 according to the embodiment of the present invention will be described. In describing the operation of the X-ray detector 100 according to the embodiment of the present invention, a thin film transistor (TFT) array substrate is exemplarily described as the substrate 110, but the present invention is not limited thereto.

The second electrode 140 is supplied with a voltage from a voltage supply source. Specifically, a positive (+) voltage or negative (-) voltage is applied from the voltage supply in consideration of the electron / hole mobility of the photoconductor layer 130 material or the ratio of the photo current to the dark current, And supply a positive (+) or negative (-) voltage to the second electrode 140.

When an X-ray passing through the second electrode 140 is absorbed by the photoconductor layer 130, an electron-hole pair is generated in the photoconductor layer 130. The amount of electron-hole pairs depends on the energy of the x-rays absorbed in the photoconductor layer 130.

A voltage is applied between the second electrode 140 and the first electrode 120 to generate a potential difference between the second electrode 140 and the first electrode 120 after the electron- The electron-hole pairs generated in the photoconductor layer 130 due to the potential difference between the second electrode 140 and the first electrode 120 are applied to the second electrode 140 and the first electrode 120 ).

For example, when a negative voltage is applied to the second electrode 140, the holes generated in the photoconductor layer 130 move toward the second electrode 140, 1 electrode (120). On the other hand, when a positive voltage is applied to the second electrode 140, the electrons generated in the photoconductor layer 130 move toward the second electrode 140 and the holes move toward the first electrode 120 do.

That is, electron-hole pairs are formed on the photoconductor layer 130 formed with the second electrode 140 by photoelectric effect when the X-ray is irradiated, and an electric field is formed by the voltage supplied to the second electrode 140 So that electrons or holes can be collected in the first electrode 120.

Charges (electrons or holes) transferred to the first electrode 120 are stored in a capacitor (not shown) formed on the substrate 110, and charges are stored in the capacitor to store the detection voltage of the X-ray.

That is, as the photoconductor layer 130 is irradiated with X-rays, a predetermined voltage is formed on a capacitor (not shown), and a predetermined voltage applied to the capacitor varies depending on the amount of X-rays irradiated to the photoconductor layer 130 This predetermined voltage can be read as an electrical signal by the operation of a thin film transistor (TFT) (not shown) formed on the substrate 110.

Specifically, when an electric signal is inputted to the thin film transistor formed on the substrate 110 and the thin film transistor is turned on, the electric charge stored in the capacitor is transmitted to the signal processing unit (not shown) through the drain electrode of the thin film transistor, The processor can implement an image by measuring the x-ray transmittance of the measurement object with the amount of charge.

The X-ray detector 100 according to the embodiment of the present invention has high sensitivity and high performance and is applicable to a medical X-ray detector for chest or dental use, an industrial X-ray defect detector, an X-ray spectrometer or a high resolution X- It is possible.

In addition, the X-ray detector 100 according to the embodiment of the present invention recognizes an image of a local region that can not be recognized by a conventional indirect X-ray detector, thereby obtaining an image of high resolution through radiography, It can be used for structural analysis.

Up to now, the Schottky type X-ray detector has been described with reference to FIG. Hereinafter, the X-ray detector of the heterojunction type will be described with reference to FIGS. 4A to 4F.

FIGS. 4A through 4F are cross-sectional views of a heterojunction X-ray detector according to an embodiment of the present invention.

4A is a cross-sectional view of a PN type X-ray detector according to an embodiment of the present invention.

4A, the x-ray detector 200a includes a substrate 210, a first electrode 220, an electron transport layer 250, a photoconductor layer 230, and a second electrode 240.

4A has the same components as those of FIG. 1 (Schottky type) except that the electron transport layer 250 is formed between the first electrode 220 and the photoconductor layer 230, so that detailed A description thereof will be omitted.

The electron transporting layer 250 may be formed of, for example, titanium oxide (TiO _x ), zinc oxide (ZnO _x ), indium oxide (InO _x ), tin oxide (SnO _x ), tungsten oxide (WO _x ), niobium oxide _x), molybdenum oxide (MoO _x), magnesium oxide (MgO _x), zirconium oxide (ZrO _x), strontium oxide (SrO _x), lanthanum oxide (LaO _x), vanadium oxide (VO _x), aluminum oxide (AlO _x ), yttrium oxide (YO _x), scandium oxide (which may be formed to include a ScO _x), gallium oxide (GaO _x), indium oxide (InO _x), mixtures thereof, or their complexes.

The electron transport layer 250 may be formed through various solution coating methods and deposition methods using a solution.

The solution coating method includes, for example, spin coating, spray coating, ultra-spray coating, electrospin coating, slot die coating, gravure coating, A roll coating, a dip coating, a shear coating, a screen printing, an inkjet printing, or a nozzle printing, .

The deposition method may be performed by, for example, sputtering, atomic layer deposition (ALD), chemical vapor deposition (CVD), thermal evaporation, co-evaporation, or the like, at a reduced pressure, Plasma enhanced chemical vapor deposition (PECVD), and the like.

The electron transport layer 250 is a layer that moves electrons to the photoconductor layer 230 so that electrons are effectively transferred to the photoconductor layer 230 and the density of holes and electrons in the photoconductor layer 230 is balanced So that the efficiency can be improved.

The electron transport layer 250 allows the electrons generated in the photoconductor layer 230 to be smoothly transferred to the first electrode 220 or the second electrode 240 and thereby reduce the dark current .

4B is a cross-sectional view of an X-ray detector according to an embodiment of the present invention.

Referring to FIG. 4B, the X-ray detector 200b includes a substrate 210, a first electrode 220, a photoconductor layer 230, an electron transport layer 250, and a second electrode 240.

Figure 4b has the same components as Figure 1 (Schottky) except that an electron transport layer 250 is formed between the photoconductor layer 230 and the second electrode 240, A description thereof will be omitted.

The electron transport layer 250 allows the electrons generated in the photoconductor layer 230 to be smoothly transferred to the first electrode 220 or the second electrode 240 and thereby reduce the dark current as compared with the Schottky type .

4C is a cross-sectional view of a PIN type X-ray detector according to an embodiment of the present invention.

Referring to FIG. 4C, the X-ray detector 200c includes a substrate 210, a first electrode 220, an electron transport layer 250, a photoconductor layer 230, a hole transport layer 260, and a second electrode 240 ).

4C has the same components as those of FIG. 4A except that the hole transport layer 260 is further formed between the photoconductor layer 230 and the second electrode 240. Therefore, detailed description of the overlapping components is omitted .

The hole transport layer 260 may be formed to include at least one of thiophene, paraphenylene vinylene, carbazole, or triphenylamine material, for example.

The hole transport layer 260 may be formed by various solution coating methods and deposition methods using a solution.

The solution coating method includes, for example, spin coating, spray coating, ultra-spray coating, electrospin coating, slot die coating, gravure coating, A roll coating, a dip coating, a shear coating, a screen printing, an inkjet printing, or a nozzle printing, .

The deposition method may be performed by, for example, sputtering, atomic layer deposition (ALD), chemical vapor deposition (CVD), thermal evaporation, co-evaporation, or the like, at a reduced pressure, Plasma enhanced chemical vapor deposition (PECVD), and the like.

The hole transport layer 260 is a layer that moves holes to the photoconductor layer 230 so that the holes are effectively transferred to the photoconductor layer 230 and the density of holes and electrons is balanced in the photoconductor layer 230 So that the efficiency can be improved.

The hole transport layer 260 allows the holes generated in the photoconductor layer 230 to smoothly move to the first electrode (or the second electrode), and to reduce the dark current as compared with the Schottky type.

4D is a cross-sectional view of an NIP type X-ray detector according to an embodiment of the present invention.

4D, the X-ray detector 200d includes a substrate 210, a first electrode 220, a hole transport layer 260, a photoconductor layer 230, an electron transport layer 250, and a second electrode 240 ).

4D has the same components as those of FIG. 4B except that a hole transport layer 260 is additionally formed between the first electrode 220 and the photoconductor layer 230. Therefore, a detailed description of the overlapping components is omitted .

The NIP type X-ray detector according to the embodiment of the present invention can reduce the dark current as compared with the Schottky type, PN type and NP type.

4E is a cross-sectional view of a PIP type X-ray detector according to an embodiment of the present invention.

4E, the X-ray detector 200e includes a substrate 210, a first electrode 220, a hole transport layer 260, a photoconductor layer 230, a hole transport layer 260, and a second electrode 240 ).

4E has the same components as those of FIG. 4C except that the hole transport layer 260 is formed between the first electrode 220 and the photoconductor layer 230 instead of the electron transport layer 250. Therefore, A detailed description of the elements will be omitted.

The PIP type X-ray detector according to the embodiment of the present invention can reduce the dark current as compared with the Schottky type, PN type and NP type.

FIG. 4F shows a cross-sectional view of an X-ray detector according to an embodiment of the present invention of the NIN type.

4f, the x-ray detector 200f includes a substrate 110, a first electrode 220, an electron transport layer 250, a photoconductor layer 230, an electron transport layer 250, and a second electrode 240 ).

4F has the same components as those of FIG. 4A except that the electron transport layer 250 is further formed between the photoconductor layer 230 and the second electrode 240. Therefore, detailed description of the overlapping components is omitted .

The NIN type X-ray detector according to the embodiment of the present invention can reduce the dark current as compared with the Schottky type, PN type and NP type.

Hereinafter, an X-ray system including an X-ray detector according to an embodiment of the present invention will be described with reference to FIG.

5 illustrates an x-ray system including an x-ray detector according to an embodiment of the present invention.

FIG. 5 illustrates the use of an X-ray system according to an embodiment of the present invention in a medical field, but the present invention is not limited thereto and can be applied to various fields such as a semiconductor field or an industrial field.

5, an X-ray system 300 includes an X-ray generator 310 for generating an X-ray 311, an X-ray detector 100 for detecting an X-ray, a driving unit 320 for driving the X-ray detector 100, A data processing unit 330 for processing the X-ray detection voltage of the detector 100, a video signal output unit 340 for outputting a video output signal in accordance with the X-ray detection voltage, and a display device 350 for outputting video in accordance with the video signal .

The X-ray 311 generated in the X-ray generator 310 can be irradiated onto the region to be inspected 361 of the patient 360. The x-ray transmitted through the inspected region 361 of the patient 360 can be irradiated to the x-ray detector 100. [

The X-ray generator 310 is a polychromatic system which is effective for measuring a fluorescent light or the like and may be arranged in any one of linear, circular, arc-shaped, or combinations thereof depending on the type of the object to be imaged and the usage environment of the X- And the array density can be adjusted.

Also, the x-ray generator 310 may be one unit x-ray generator or a plurality of unit x-ray generators, and may be a gentry x-ray generator.

The x-ray generator 310 may include a cathode electrode, an emitter, an anode electrode, a gate electrode, a focusing electrode, and one or more insulating pillars. Also, the x-ray generator 310 may be operated in vacuum.

The cathode electrode is located on a substrate formed of glass, metal, quartz, silicon or alumina, and an emitter in the form of a point light source and / or a surface light source is disposed on the cathode electrode.

The emitter serves to emit electrons and may have a point light source shape. Such an emitter in the form of a point light source is not particularly limited in its shape as long as the tip at which electrons are emitted has a pointed shape. Preferably, however, it may be any one of a conical shape, a tetragonal shape, a cylindrical shape with a pointed tip and a polyhedral shape with a pointed tip.

In addition, the type of the emitter is not particularly limited, but a conductive material composed of a metal or a carbon-based material may be used.

On the other hand, the emitter can be a surface light source type emitter as well as a point light source type in accordance with the performance of the desired x-ray generator or the like. In this case, the emitter in the form of a surface light source may be a silicon, A carbon structure or metal formed thereon may be used.

The anode electrode may be formed on the emitter, and the anode electrode may be formed with an electrode and / or a DC power supply for applying power.

The anode electrode material may generally comprise copper, tungsten, manganese, maldives, or a combination thereof. In the case of thin film x-rays, the anode electrode may be formed of a metal thin film.

With this configuration, when the emitter emits electrons, the emitted electrons can collide with the metal constituting the anode electrode, and then generate the X-rays while reflecting or passing through the metal.

The X-ray detector 100 may provide the X-ray detection voltage corresponding to the intensity of the provided X-ray 311 to the display device 350 via the data processing unit 330 and the video signal output unit 340.

The x-ray detector 100 comprises a photoconductor layer comprising a perovskite compound according to an embodiment of the present invention.

Since the X-ray detector 100 has the same components as those of FIG. 1, detailed description of the redundant components will be omitted.

The display device 350 can display an x-ray image corresponding to a video signal in real time. For example, the display device 350 may include a liquid crystal display (LCD).

Hereinafter, an X-ray diffraction (XRD) analysis apparatus including an X-ray detector according to an embodiment of the present invention will be described with reference to FIG.

6 is an image showing an X-ray diffraction (XRD) analysis apparatus according to an embodiment of the present invention.

An x-ray detector according to embodiments of the present invention may be used in an x-ray diffraction (XRD) analyzer.

6, an X-ray diffraction (XRD) analyzer 400 includes an X-ray generator 420 for irradiating an X-ray and an X-ray detector 430 for detecting an X-ray reflected or diffracted against the inspected object 410 .

The subject 410 may be spaced apart from the X-ray detector 430 by a predetermined distance and the X-ray generator 420 and the X-ray detector 430 may be arranged to have a predetermined angle around the subject 410. However, the predetermined distance and angle may be changed according to the type of X-ray system and the use environment.

Since the X-ray generator 420 has the same components as those of FIG. 5, detailed description of the overlapping components will be omitted.

X-ray detector 430 comprises a photoconductor layer comprising a perovskite compound according to an embodiment of the present invention. Since the X-ray detector 430 has the same components as those of FIG. 1, detailed description of the redundant components will be omitted.

The X-ray diffraction (XRD) analyzer 400 includes the X-ray detector 430 according to the embodiment of the present invention, thereby improving the durability and stability of the X-ray.

In addition, the X-ray diffraction (XRD) analyzer 400 recognizes an image of a local area by using the X-ray detector 430 according to an embodiment of the present invention, thereby obtaining a high-resolution image through X-ray imaging, It can be used for analysis and can improve performance.

Also, the X-ray diffraction (XRD) analyzer 400 can obtain the pattern from a plurality of diffraction peaks having different intensities by recording the intensity of the diffracted X-ray while changing the angle of the X-ray to the sample to be measured. Through this, the composition of the material can be analyzed and the orientation of the material can be measured and analyzed.

Hereinafter, an application field of the nondestructive inspection apparatus including the X-ray detector according to the embodiment of the present invention will be described with reference to FIG.

7 is an image showing an application field of the nondestructive inspection apparatus according to the embodiment of the present invention.

The nondestructive inspection apparatus according to an embodiment of the present invention includes an x-ray generator for irradiating x-rays and an x-ray detector according to an embodiment of the present invention for detecting x-rays transmitted through the inspected object.

Since the X-ray generator has the same components as those of FIG. 5, detailed description of the redundant components will be omitted.

The x-ray detector is placed on the opposite side of the x-ray generator across the inspected object.

The x-ray detector comprises a photoconductor layer comprising a perovskite compound according to an embodiment of the present invention.

Since the X-ray detector has the same components as those of FIG. 1, a detailed description of the overlapping components will be omitted.

The nondestructive inspection apparatus according to the embodiment of the present invention includes the x-ray detector according to the embodiment of the present invention, thereby improving the durability and stability of the x-ray.

In addition, the nondestructive inspection apparatus according to the embodiment of the present invention recognizes an image of a local area by using an X-ray detector according to an embodiment of the present invention, thereby obtaining a high-resolution image through X-ray imaging, And it is possible to improve the performance.

On the other hand, various structures (semiconductor materials, petroleum piping, tools, structures, repair inspection, etc.) are rapidly becoming large-sized, high-pressure or high-speed, bringing about a great change in its quality and scale, It is becoming a problem.

Since all materials can not be permanently bonded, their lifespan can not be permanent, so they not only have defects in the material but also affect the life of the material as defects occur and grow during and during processing.

The nondestructive inspection apparatus according to an embodiment of the present invention can provide data to determine how much defects exist in such a structure and how harmful the defects are in their use conditions. That is, by checking the state of the structure using the non-destructive testing apparatus according to the embodiment of the present invention, it is possible to prolong the lifetime by recording in advance a defect or the like which is deemed to be harmful.

The X-ray detector according to the embodiment of the present invention is applied in different fields depending on the tube voltage. The tube voltage and spatial resolution according to the application fields of the X-ray detector are shown in Table 1 below.

Applications Tube Voltage (kpV) Spatial resolution (lp / mm) Crystallography 8-20 10 Nondestructive inspection 30-600 5-10 thorax 80-150 ~ 6 Mommo 20-30 15-20 Dental 50-70 7-10 Micro CT 24-50 20

Referring to Table 1, for example, in the case of mammomas, the tube voltage may be lowered because there is no bone. However, in the case of the thorax, the tube voltage is greatly examined because it is composed of bone and blood. Thus, depending on the application, the tube voltage is measured differently in the x-ray detector.

In addition, the thickness of the photoconductor layer will vary as the tube voltage is varied. Specifically, in order to absorb photons of a larger energy, the thickness of the photoconductor layer must be made thick, and the thickness of the photoconductor layer may vary depending on the constituent elements of the photoconductor layer.

It is ideal to absorb more than 90% of the X-rays in the photoconductor layer in order to minimize the damage of the transistors and capacitors of the array substrate due to the high energy of the X-rays, but this has a disadvantage that the thickness of the photoconductor layer becomes thick . Thus, a photoconductor layer that absorbs at least 10% should be fabricated, preferably with a thickness that has an absorption of at least 63%.

Hereinafter, examples and comparative examples of the present invention will be described. The following examples are merely examples of the present invention and the present invention is not limited to the following examples.

Example

Example  One

An X-ray detector having a Cs ₃ Bi ₂ I ₉ photoconductor layer was prepared.

A glass substrate (FTO: F-doped SnO ₂ , 8 ohms / sq, Pilkington, hereinafter referred to as FTO substrate) coated with fluorine-containing tin oxide was cut into a size of 25.times.25 mm and the end portion (10 mm) To remove the FTO.

A TiO ₂ thin film having a dense structure of about 50 nm thickness as an electron transport layer was prepared by spray pyrolysis deposition on cut and partially etched FTO substrates. Spray pyrolysis was carried out by spraying on 450 ° C FTO substrate using TAA (Titanium acetylacetonate): EtOH (1: 9 v / v%) solution.

Cs ₃ Bi ₂ I for the preparation of ₉ solution, CsI powder and BiI ₃ powder to 1: DMF (N, N, dimethyl formamide, N, N, dimethylformamide) at a molar ratio of 1: 1 into the solvent at 60 ℃ 30 Lt; / RTI &gt; The prepared Cs ₃ Bi ₂ I ₉ solution was Cs ₃ Bi ₂ I ₉ The content is 40 wt%.

Since, in which a hot plate kept at 120 ℃ (hot plate) by disposing an electron transport layer / an etched FTO substrate and spray coated with Cs ₃ Bi ₂ I ₉ solution on the electron transfer layer / etched FTO substrate about 100 ㎛ in Thick photoconductor layer.

Thereafter, a gold (Au) electrode having a thickness of about 60 nm was formed on the photoconductor layer / electron transport layer / FTO substrate using a thermal evaporator. Here, the area of the photoconductor layer was fixed at 1 cm 2.

Example  2

An X-ray detector with MA ₃ Bi ₂ I ₉ photoconductor layer was prepared.

An X-ray detector was prepared in the same manner as in Example 1 except that the material of the perovskite compound was changed to MA ₃ Bi ₂ I ₉ in Example 1.

For the preparation of the MA ₃ Bi ₂ I ₉ solution, MAI powder and BiI ₃ powder were dissolved in DMF solvent at a molar ratio of 1: 1 for 30 minutes at 60 ° C. Here, the prepared MA ₃ Bi ₂ I ₉ solution has a MA ₃ Bi ₂ I ₉ content of 40 wt%.

Comparative Example  One

An x-ray detector with a cadmium telluride (CdTe) photoconductor layer was prepared.

About 700 nm titanium (Ti) electrodes were deposited on a typical silicon (Si) substrate by sputtering. Then, a sintered high purity CdTe powder (99.99%) was formed on the Ti / Si substrate using a thermal evaporator to form a photoconductor layer having a thickness of about 160 μm. A 60 ㎚ thick Au electrode was formed on the CdTe / Ti / Si substrate using a thermal evaporator.

Character rating

Table 2 below shows the x-ray detector comprising the perovskite compound photoconductor layer according to Examples 1 to 2 and the manufacturing method conditions of the x-ray detector including the cadmium telluride (CdTe) photoconductor layer according to Comparative Example 1 .

Examples 1 to 2 Comparative Example 1 Sample preparation method Spray coating
(Spray Coating) Thermal deposition
(Thermal Evaporator) Estimated time for one process ~ 180 minutes ~ 900 minutes Process temperature 120 DEG C ~ 400 ° C Vacuum No vacuum required
(No Vacuum) High vacuum
(2 x 10 ^-5 Torr) Expected material cost Within 10 Within 1.5 million won

Referring to Table 2, by forming a photoconductor layer comprising a perovskite compound according to an embodiment of the present invention using a solution process (spray coating), a photoconductor layer including cadmiumdeluide (CdTe) It can be confirmed that the material cost can be reduced due to the short time, low temperature and vacuum process conditions.

8 is an X-ray diffraction (XRD) analysis graph of a photoconductor layer comprising the perovskite compound prepared in Example 1. FIG.

Referring to Figure 8, Cs ₃ Bi ₂ I through ₉ to the peak of (006) peak associated with the material observed, it can be seen the photoconductor layer well formed of a material of Cs ₃ Bi ₂ I ₉ structure.

In order to observe the cross section of the x-ray detector with the photoconductor layer comprising the perovskite compound prepared in Example 1, it was observed with a scanning electron microscope (SEM).

9 is a scanning electron microscope (SEM) image of a photoconductor layer comprising the perovskite compound prepared in Example 1. Fig.

Referring to FIG. 9, it can be seen that the Cs ₃ Bi ₂ I ₉ photoconductor layer prepared in Example 1 having the structure of A ₃ M ₂ X ₉ is well formed on the TiO ₂ / FTO substrate to a thickness of about 100 μm have.

Through this, it can be confirmed that high resolution image can be realized because the charge generation is smoothly performed even at low voltage and dose due to the property of the perovskite material having small electron-hole pair generation energy and low trap density.

An X-ray detector manufactured by Example 1, Example 2 and Comparative Example 1 was irradiated with an X-ray (equipment name: ORTHOCEPH-OC-100, company: Instrumentarium Imaging Dental, tube voltage: 77 kVp, tube current: 12 mA) The current density was recorded and shown in Table 3 below.

Example 1 Example 2 Comparative Example 1 Current density (A / cm ² ) in X-ray on state 33 * 10 ^-6 25 * 10 ^-6 0.047 * 10 ^-6 Current density (A / cm ² ) in X-ray off state 5 * 10 ^-6 7 * 10 ^-6 0.032 * 10 ^-6

Referring to Table 3, the x-ray detector with the photoconductor layer comprising the perovskite compound prepared in Examples 1 and 2 has the same x-ray detector as the x-ray detector with the photoconductor layer comprising the CdTe of Comparative Example 1, It can be seen that the current density was improved about 1,000 times more when irradiated.

FIGS. 10A and 10B are graphs _showing Cs ₃ Bi ₂ I ₉ Ray detectors with a photoconductor layer comprising perovskite compound and CdTe.

Specifically, Cs ₃ Bi ₂ I ₉ prepared in Example 1 Ray detector having a photoconductor layer including a perovskite compound and a photoconductor layer including a CdTe layer prepared in Comparative Example 1 was fixed at -2 V and the X-ray was irradiated for 1 second (s) and observed x-ray reactivity.

Referring to FIG. 10A, the change of the current density according to the X-ray irradiation time is shown in Example 1 (Cs ₃ Bi ₂ I ₉ In the case of the x-ray detector of the perovskite compound, the rising time of the current at the time of turning on the X-ray is very fast, and it can be confirmed that the X-ray is quickly returned to the dark current state when the X-ray is off. Thus, (MA) ₃ Pb ₂ I ₉ It can be confirmed that the trap density of the photoconductor layer including the perovskite compound is low and high resolution image without image lag can be realized.

On the other hand, in the case of the X-ray detector of Comparative Example 1 (CdTe), it can be seen that the current is sharply lowered in X-ray irradiation under the same conditions as in Example 1 (Cs ₃ Bi ₂ I ₉ perovskite compound). This is because the Cs ₃ Bi ₂ I ₉ of Example 1 Compared to the perovskite compound, the generation of electrons and holes is remarkably low, or the trap density is high, so that electrons or holes are difficult to move toward the pixel side, and current can be formed to a low level.

Referring to FIG. 10B, the current rise time and the decay time of the X-ray detector of Example 1 and Comparative Example 1 can be confirmed.

As shown in FIG. 10B, the current rise time is much slower than that of the first embodiment in Comparative Example 1, and it can be confirmed that a long time is required to return to the dark current state even when the X-ray is off. As a result, the trap density of the CdTe photoconductor layer of Comparative Example 1 is high and it can be confirmed that it is difficult to use the CdTe photoconductor layer as a moving image sensor.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

100, 200a-200f, 430: X-ray detector
110, 210: substrate
120, 220: a first electrode (pixel electrode)
130, 230: photoconductor layer
140, 240: a second electrode (common electrode)
250: electron transport layer
260: hole transport layer
300: X-ray system
310: X-ray generator
311: X-ray
320:
330: Data processor
340: Video signal output section
350: Display device
360: patient
361: the part to be examined
410:
420: X-ray generator

Claims (28)

Board;
A first electrode formed on the substrate;
A photoconductor layer formed on the first electrode and generating electron-hole pairs by an incident X-ray; And
And a second electrode formed on the photoconductor layer
/ RTI &gt;
Wherein the photoconductor layer comprises a perovskite compound represented by the following Formula 1,
Wherein the thickness of the photoconductor layer is from 1 占 퐉 to 1,000 占 퐉 and the trap density of the photoconductor layer is from 10 ⁸ cm ^-2 to 10 ¹⁶ cm ^-2 .
[Chemical Formula 1]
A ₃ M ₂ X ₉
(In the formula 1,
A is a monovalent cation,
M is a trivalent metal cation,
X is a monovalent anion.) The method according to claim 1,
And A is straight or branched chain alkyl group, a C _{1 ~ 24} amine (-NH _3), hydroxyl groups (-OH), cyano group (-CN), a halogen group, a nitro group (-NO), a methoxy group (-OCH ₃ ) or imidazolium group substituted linear or branched C _{1 ~ 24} ^{alkyl, Li +, Na +, K} +, Rb +, Cs +, Fr +, Cu (I) +, Ag (I) + and Au ( I) ^&lt; / RTI &gt; ⁺ . & Lt ^{; /} RTI &^gt; The method according to claim 1,
Wherein M is a ^{3 +} In, Bi ^{+ 3,} Co ^{+ 3,} Sb ^{+ 3,} Ni ^{+ 3,} Al ^{+ 3,} Ga ^{+ 3,} Tl ^{+ 3,} Sc ^{+ 3,} Y ^3+, La ^{+ 3,} Ce ^{+ 3} , the x-ray detector comprises at least one selected from ^{Fe 3+, Ru 3 +, Cr} 3 +, V 3+ and the group consisting of Ti ^{3 +.} The method according to claim 1,
X is at least one selected from the group consisting of F ^- , Cl ^- , Br ^- , I ^- , SCN ^- and BF ₄ ^- . The method according to claim 1,
Wherein the perovskite compound is nanocrystalline particles. 6. The method of claim 5,
Wherein the particle size of the nanocrystalline particles is in the range of 1 nm to 500 nm. delete The method according to claim 1,
Wherein the photoconductor layer further comprises a trap healing material. 9. The method of claim 8,
Wherein the trapping healing material comprises at least one selected from the group consisting of graphene quantum dots, fullerene, C ₆₀ , or derivatives thereof. The method according to claim 1,
Wherein the photoconductor layer further comprises an organic binder. 11. The method of claim 10,
Wherein the organic binder is selected from the group consisting of polyvinyl butyral resin, polyvinyl chloride resin, acrylic resin, phenoxy resin, polyester resin, polyvinyl formal resin, polyamide resin, polystyrene resin, polycarbonate resin, polyvinyl acetate resin, polyurethane A resin, and an epoxy resin. 11. The method of claim 10,
Wherein the photoconductor layer comprises the perovskite compound and the organic binder in a weight ratio of 90:10 to 10:90. The method according to claim 1,
Wherein the photoconductor layer further comprises an inorganic binder. 14. The method of claim 13,
Wherein the inorganic binder comprises at least any one selected from the group consisting of TiO ₂ nanoparticles, SiO ₂ nanoparticles, Al ₂ O ₃ nanoparticles, VO ₂ nanoparticles, layered compounds, metal alkoxides and metal halides X-ray detector. 14. The method of claim 13,
Wherein the photoconductor layer comprises the perovskite compound and the inorganic binder in a weight ratio of 90:10 to 10:90. 14. The method of claim 13,
Wherein the particle size of the inorganic binder ranges from 1 nm to 100 nm. delete The method according to claim 1,
The first electrode may be formed of one selected from the group consisting of Al, Ag, Au, Cu, Pd, Pt, ITO, AZO, Wherein at least one selected from the group consisting of tin oxide (FTO), carbon nanotube (CNT), graphene, and polyethylene dioxythiophene: polystyrene sulfonate (PEDOT: PSS) is contained. The method according to claim 1,
The second electrode may be formed of at least one selected from the group consisting of Al, Ag, Au, Cu, Pd, Pt, ITO, AZO, Wherein at least one selected from the group consisting of tin oxide (FTO), carbon nanotube (CNT), graphene, and polyethylene dioxythiophene: polystyrene sulfonate (PEDOT: PSS) is contained. The method according to claim 1,
And an electron transfer layer between the first electrode and the second electrode. 21. The method of claim 20,
Wherein the electron transport layer comprises a metal oxide. The method according to claim 1,
And a hole transport layer between the first electrode and the second electrode. 23. The method of claim 22,
Wherein the hole transporting layer comprises at least one selected from the group consisting of thiophene, paraphenylene vinylene, carbazole, and triphenylamine. The method according to claim 1,
Wherein the substrate comprises any one selected from the group consisting of glass, quartz, silicon, and plastic. The method according to claim 1,
Wherein the substrate is an array substrate comprising a thin film transistor (TFT), a charge coupled device (CCD), or a complementary metal oxide semiconductor (CMOS). An x-ray generator generating an x-ray;
An x-ray detector according to any one of claims 1 to 6, 8 to 16 and 18 to 25 for detecting the x-ray;
A driving unit for driving the X-ray detector; And
A data processor for processing the X-ray detection voltage
. &Lt; / RTI &gt; 27. The method of claim 26,
Wherein the x-ray system is an x-ray diffraction analyzer (XRD). 27. The method of claim 26,
Wherein the x-ray system is a non-destructive inspection apparatus.

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