KR101960227B1 - X-ray detector having band offset structure - Google Patents

Abstract

The present invention discloses an x-ray detector including a band offset structure. 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, the electron transport layer being formed on one side of the photoconductor layer, wherein the band gap energy of the electron transport layer is greater than the band gap energy of the photoconductor layer Ray detector that reduces a dark current by forming a barrier between the photoconductor layer and the electron transporting layer by having a value of a thickness of the electron transport layer and an X-ray system including the same.

Description

X-RAY DETECTOR HAVING BAND OFFSET STRUCTURE < RTI ID = 0.0 >

The present invention relates to an x-ray detector comprising a band offset structure.

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.

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.

On the other hand, since the current generated in the photoconductor layer is low in the x-ray detector currently used, researches for increasing the image resolution in the array substrate have been conducted.

However, there is a limitation that it can be represented only by 0 and 1, so that the image can be obtained only in the part other than the bones and bones. For example, in the case of bones, high energy (100-120 kVp) is required for detection, and tumors can be detected at a low energy of ~ 50 kVp or less.

On the other hand, in the case of a-Se which is mainly used in the photoconductor layer of the x-ray detector, the resolution is focused on the low-dose x-ray, which limits the detection of the high dose x-ray.

In addition, up to now, the direct-type X-ray detector has a problem in that, even when no light is irradiated, electrons or holes move to the electrodes and a dark current corresponding to noise occurs at a signal / noise ratio, Is low.

Therefore, it is necessary to develop a high-resolution X-ray detector that does not generate dark current when light is not irradiated.

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 is to provide an X-ray detector including a band offset structure.

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, the electron transport layer being formed on one side of the photoconductor layer, wherein the band gap energy of the electron transport layer is greater than the band gap energy of the photoconductor layer .

The band gap energy of the electron transport layer may have a large value of 0.02 eV to 0.5 eV than the band gap energy of the photoconductor layer.

And an electron transport layer or a hole transport layer formed on the other surface of the photoconductor layer. The band gap energy of the electron transport layer or the hole transport layer may have a value larger than a band gap energy of the photoconductor layer.

The band gap energy of the electron transport layer may have a large value of 0.02 eV to 0.5 eV than the band gap energy of the photoconductor layer.

The band gap energy of the hole transport layer may have a larger value of 0.02 eV to 0.5 eV than the band gap energy of the photoconductor layer.

The electron transport layer may include any one selected from the group consisting of ZnO (Zinc oxide), Phenyl-C61-butyric acid methyl ester (PCBM), Al ₂ O ₃ (Aluminum oxide), and TiO ₂ have.

Wherein the hole transport layer is selected from the group consisting of NiO (Nickel oxide), CuI (Copper (I) iodide), CuSCN (Copper (I) thiocyanate), and P3HT (Poly (3-hexylthiophene-2,5-diyl) And may include any one of them.

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

[Chemical Formula 1]

AMX ₃

Wherein A is a monovalent cation, M is a divalent metal cation, and X is a monovalent anion.

The photoconductor layer may include a perovskite compound represented by the following formula (2).

(2)

A ₃ M ₂ X ₉

Wherein A is a monovalent cation, M is a trivalent metal cation, and X is a monovalent anion.

The photoconductor layer may include a perovskite compound represented by the following formula (3).

(3)

A ₃ MX ₆

Wherein A is a monovalent cation, M is a trivalent metal cation, and X is a monovalent anion.

The photoconductor layer may include a perovskite compound represented by the following formula (4).

[Chemical Formula 4]

AM ₂ X ₇

Wherein A is a monovalent cation, M is a trivalent metal cation, and X is a monovalent anion.

The photoconductor layer may comprise a perovskite compound represented by the following formula (5).

[Chemical Formula 5]

A ₂ A ' _{n - 1} M _n X _{3n +1}

(Wherein A is a monovalent cation, A 'is a monovalent cation, M is a monovalent, divalent, trivalent or tetravalent metal cation, X is a monovalent anion, and n is at least one .)

The photoconductor layer may comprise a perovskite compound of nanocrystalline particles.

The photoconductor layer may include one selected from the group consisting of _{CdTe, PbI 2, a-Se} , PbO, HgI 2 and BiI _3.

The photoconductor layer may further comprise an organic binder.

The photoconductor further comprises an inorganic binder.

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).

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

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

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 band gap energy of the hole transport layer is greater than the band gap energy of the photoconductor layer It is characterized by large.

The band gap energy of the hole transport layer may be 0.02 eV to 0.5 eV greater than the band gap energy of the photoconductor layer

An X-ray generator for generating an X-ray according to an embodiment of the present invention includes an X-ray detector according to any one of claims 1 to 22 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 may be an x-ray diffraction analyzer (XRD).

The x-ray system may be a non-destructive testing device.

According to embodiments of the present invention, the X-ray detector forms a barrier by a band offset structure formed between the photoconductor layer and the electron transport layer or between the photoconductor layer and the hole transport layer when no light is irradiated to reduce the dark current .

Also, according to embodiments of the present invention, the X-ray detector can increase the signal / noise ratio and enable a high-resolution image to be realized.

Also, according to embodiments of the present invention, the X-ray system includes an X-ray detector capable of detecting both a high-dose X-ray and a low-dose X-ray, and can simultaneously detect bones and various organs.

Figure 1A shows a cross-sectional view of a typical x-ray detector.
1B shows an energy band diagram of the x-ray detector when no light is irradiated.
FIG. 2A is a cross-sectional view of an X-ray detector according to a first embodiment of the present invention.
FIG. 2B shows an energy band diagram of the X-ray detector according to the first embodiment of the present invention when no light is irradiated.
FIG. 2C shows an energy band diagram of the X-ray detector according to the first embodiment of the present invention when light is irradiated.
3A is a cross-sectional view of an X-ray detector according to a second embodiment of the present invention.
FIG. 3B shows an energy band diagram of the X-ray detector according to the second embodiment of the present invention when no light is irradiated.
FIG. 3C shows an energy band diagram of the X-ray detector according to the second embodiment of the present invention when light is irradiated.
4A is a cross-sectional view of an X-ray detector according to a third embodiment of the present invention.
FIG. 4B shows an energy band diagram of the X-ray detector according to the third embodiment of the present invention when no light is irradiated.
FIG. 4C shows an energy band diagram of an X-ray detector according to a third embodiment of the present invention when light is irradiated.
5A is a cross-sectional view of an X-ray detector according to a fourth embodiment of the present invention.
FIG. 5B shows an energy band diagram of the X-ray detector according to the fourth embodiment of the present invention when no light is irradiated.
FIG. 5C shows an energy band diagram of the X-ray detector according to the fourth embodiment of the present invention when light is irradiated.
6A is a cross-sectional view of an X-ray detector according to a fifth embodiment of the present invention.
6B is an energy band diagram of the X-ray detector according to the fifth embodiment of the present invention when no light is irradiated.
6C is an energy band diagram of the X-ray detector according to the fifth embodiment of the present invention when light is irradiated.
7A is a cross-sectional view of an X-ray detector according to a sixth embodiment of the present invention.
FIG. 7B shows an energy band diagram of the X-ray detector according to the sixth embodiment of the present invention when no light is irradiated.
7C shows an energy band diagram of an X-ray detector according to a sixth embodiment of the present invention when light is irradiated.
8A is a cross-sectional view of an X-ray detector according to a seventh embodiment of the present invention.
FIG. 8B shows an energy band diagram of the X-ray detector according to the seventh embodiment of the present invention when no light is irradiated.
FIG. 8C shows an energy band diagram of an X-ray detector according to a seventh embodiment of the present invention when light is irradiated.
9A is a cross-sectional view of an X-ray detector according to an eighth embodiment of the present invention.
9B shows an energy band diagram of an X-ray detector according to an eighth embodiment of the present invention when no light is irradiated.
9C shows an energy band diagram of an X-ray detector according to an eighth embodiment of the present invention when light is irradiated.
10 illustrates an x-ray system including an x-ray detector according to an embodiment of the present invention.
FIG. 11 illustrates an X-ray diffraction (XRD) analysis apparatus including an x-ray detector according to an embodiment of the present invention.
FIG. 12 illustrates an application field of a nondestructive inspection apparatus including an X-ray detector according to an embodiment of the present invention.

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.

In this specification, the photo energy band diagram shows the energy levels of the first electrode, the second electrode, the photoconductor layer, the electron transport layer, and the hole transport layer.

Figure 1A shows a cross-sectional view of a typical x-ray detector.

1A, an x-ray detector includes a substrate 10, a first electrode 20, an electron transport layer 50, a photoconductor layer 30, a hole transport layer 60 and a second electrode 40 do.

1B shows an energy band diagram of the x-ray detector according to Fig. 1A when no light is irradiated.

1B, a pair of electron-holes formed in the photoconductor layer 30 is separated into individual electrons and holes, and the separated electrons and holes move to the first electrode 20 and the second electrode 40 do. That is, the electrons move to the first electrode 20 and the holes move to the second electrode 40.

However, in the X-ray detector according to FIG. 1B, the electrons in the photoconductor layer 30 move to the first electrode 20 and the holes move to the second electrode 40 even when no light is irradiated, The dark current corresponding to the noise is generated in the ratio, and the signal / noise ratio is decreased. Therefore, the resolution of the X-ray detector is lowered.

 Therefore, the X-ray detector according to the embodiment of the present invention forms an electron transport layer or a hole transport layer containing a material having a band gap energy higher than that of the photo-conductor layer in order to prevent dark current when no light is irradiated, The signal / noise ratio can be increased to improve the resolution.

Hereinafter, an electron transport layer or a hole transport layer is formed so as to prevent a dark current, and a structural example according to the position will be described in detail with reference to FIGS. 2A to 9C.

The X-ray detector of FIGS. 2A to 9C described below may have a double hetero-junction structure.

2A to 9C described below are characterized in that the positions of the electron transport layer 150 or the hole transport layer 160 are different from each other. Therefore, the X- The electron transport layer 150 or the hole transport layer 160 may be formed on the first electrode 120, the photoconductor layer 130, the second electrode 140, the electron transport layer 150 and the hole transport layer 160, We will explain in detail the structural differences between when the light is not irradiated and when the light is irradiated.

In the X-ray detector shown in Figs. 2A to 9C described below, in order to realize a high-resolution image, the photocurrent / dark current ratio must be high, that is, the ratio of the signal value corresponding to the photocurrent to the noise value corresponding to the dark current / Noise = photocurrent / dark current) ratio should be high.

The electron transport layer 150 or the hole transport layer 160 may be formed on one side or both sides of the photoconductor layer 130 so that the electron transport layer 150 or the hole transport layer 160 may be formed on the photo- It is possible to have a band offset structure in which the band gap energy is larger than that of the contact layer and thus a barrier is formed.

The substrate 110 may be an array substrate comprising a complementary metal-oxide semiconductor (CMOS), a charge coupled device (CCD), or a thin film transistor 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 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 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. In addition, the TFT array substrate can be widely used as a detector for chest and industrial because it is easy to manufacture a large area.

In describing an X-ray detector 100 according to an embodiment of the present invention, an array substrate is exemplarily described as the substrate 110, but the present invention is not limited thereto.

The substrate 110 may be an array substrate, and the array substrate may include a thin film transistor (TFT) (not shown) and a capacitor (not shown).

A thin film transistor (TFT) (not shown) may serve as a switching element for sequentially outputting an electric signal generated in the photoconductor layer 130 to an external circuit.

In addition, a capacitor (not shown) may be provided on the substrate 110 to accumulate the converted electrical signals in the photoconductor layer 130, and a capacitor (not shown) may be provided below each thin film transistor .

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.

For example, the first electrode 120 may be a pixel electrode, but is not limited thereto.

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.

The first electrode 120 may be a pixel electrode divided into 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 nanotube (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.

The photoconductor layer 130 is a substance (x-ray absorbing material) capable of absorbing X-rays incident through the second electrode 140 and converting the X-ray into an electrical signal. The perovskite compound, CdTe , PbI ₂ , a-Se, PbO, HgI _2, and BiI ₃ .

The perovskite compound may be a compound having a perovskite structure.

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

[Chemical Formula 1]

AMX ₃

In Formula 1, A is a monovalent cation, M is a divalent 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 advantages of inorganic materials, the reproducibility is high, and the durability and stability of X-rays are improved .

On the other hand, even in the case of a perovskite compound of an inorganic metal halide, it can be easily produced in a thick film like a non-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 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 may be a ^{Pb 2 +, Sn 2 +,} Ge 2 +, Cu 2 +, Co 2 +, Ni 2 +, Ti 2 +, Zr 2 +, Hf 2 +, Rf 2 + , or a combination thereof.

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

The perovskite compound may be a perovskite compound represented by the following formula (2). That is, the photoconductor layer 130 may include a perovskite compound represented by the following formula (2).

(2)

A ₃ M ₂ X ₉

In Formula 2, 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.

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 perovskite compound may be a perovskite compound represented by the following formula (3). That is, the photoconductor layer 130 may include a perovskite compound represented by the following formula (3).

(3)

A ₃ MX ₆

In Formula 3, 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.

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 perovskite compound may be a perovskite compound represented by the following formula (4). That is, the photoconductor layer 130 may include a perovskite compound represented by the following formula (4).

[Chemical Formula 4]

AM ₂ X ₇

In Formula 4, 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.

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 perovskite compound may be a perovskite compound represented by the following formula (5). That is, the photoconductor layer 130 may include a perovskite compound represented by the following formula (5).

[Chemical Formula 5]

A ₂ A ' _{n - 1} M _n X _{3n +1}

In Formula 5, A is a monovalent cation, A 'is a monovalent cation, M is a monovalent, divalent, trivalent or tetravalent metal cation, X is a monovalent anion, and n is at least one .

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

The A or A 'may include a compound represented by the following formulas (6) to (8).

[Chemical Formula 6]

H ₃ NR-NH ₃

(7)

[Chemical Formula 8]

In the above Chemical Formulas 6 to 8, B is a nonmetal, a transition metal or a metal having a trifunctional bond or more, R to R4 are C _{2 to} C ₂₀ unsubstituted or substituted alkyl groups, and the substituent is an amino group (-NH ₃ ), A hydroxyl group (-OH), a cyano group (-CN), a halogen group, a nitro group (-NO), a methoxy group (-OCH ₃ ) or a combination thereof.

When the compound of Formula 6 to Formula 8 is included, the durability can be enhanced and the stability to light can be improved.

Wherein M is ^{Li +, Na +, K +} , Rb +, Cs +, Pb 2 +, Sn 2 +, Ge 2 +, Cu 2 +, Co 2 +, Ni 2 +, Ti 2 +, Zr 2+, ^{2 +} Hf, Rf ^{2 +,} In ^{+ 3,} 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,} Si ^{+ 4,} C ^4+, Ge ^{+ 4,} Hf ^{+ 4,} Zr ^{+ 4,} Ti ^{+ 4,} or Or a combination thereof.

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

If n is 1, the perovskite compound has a two-dimensional (2D) structure, and if n is infinite, the perovskite compound can have a three-dimensional (3D) structure.

In addition, the perovskite compound may have a two-dimensional structure and a two-dimensional or three-dimensional structure.

The perovskite compound having the structure of the formula (5) has a two-dimensional structure, so that the durability can be improved.

Further, the perovskite compound having the structure of the formula (5) has a three-dimensional structure, so that the absorption rate of X-rays can be improved.

The perovskite compound may be in the form of a plurality of nanocrystalline particles (hereinafter, referred to as perovskite nanocrystal particles). That is, the photoconductor layer 130 may comprise a perovskite compound of 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 impossible to apply to a 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 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 contain an x-ray absorbing material (e.g., 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 weight ratio described above, The amount of electrons and holes is reduced, resulting in degraded resolution and resolution, which may degrade 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.

The photoconductor layer 130 may contain an x-ray absorbing material (e.g., perovskite compound) and an inorganic binder in a weight ratio of 90:10 to 10:90.

If 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 130 is reduced, resulting in degraded resolution and resolution. As a result, It may degrade performance.

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 or a deposition method using an X-ray absorbing material-containing solution in which the X-ray absorbing material is dissolved in a solvent.

When the photoconductor layer 130 is formed using a solution coating method, the manufacturing process can be simplified and the manufacturing cost can be reduced.

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 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 by the first electrode 120 without an external applied voltage, An electric field may be formed to collect electrons or holes toward the first 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.

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.

According to one aspect of the present invention, when the photoconductor layer 130 is formed to include a perovskite compound, it is possible to prevent a delay in the time the charge generated in the photoconductor layer 130 is trapped in the trap And has a high response speed, which is excellent in sensitivity, light absorption characteristics and time resolution for an X-ray, and can have low resistance characteristics.

In addition, the x-ray detector according to the embodiment of the present invention includes the photoconductor layer 130 including the perovskite compound, so that it is possible to detect both the high dose x-rays and the low dose x- Can be detected simultaneously.

According to one aspect of the present invention, when the photoconductor layer 130 is formed to include at least one of CdTe, PbI ₂ , a-Se, PbO, HgI ₂ and BiI ₃ , The X-ray image of high efficiency can be obtained.

For example, when the chest is photographed, the contact pressure is irradiated at 100 kVp, where the photon energy generated by the metal is 0 eV to 100 eV. Among them, electrons corresponding to 50 eV are most generated at the center wavelength, and have a Gaussian distribution. However, these electrons are not all the necessary energy for chest radiography, and photon energy other than the central wavelength of 50 eV is all unnecessary energy.

In other words, these photon energies play a role of noise, which may cause degradation of resolution.

Accordingly, in the embodiment of the present invention, unnecessary energy serving as noise is absorbed by other photoelectric materials, and thus it can be used to acquire images of other organs and tumors in the human body.

A second electrode 140 is formed on the photoconductor layer 130. The second electrode 140 may be used as a common electrode, but is not limited thereto. The second electrode 140 may have a single electrode structure formed to cover the first electrode 120.

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 (Al), silver (Ag), gold (Au), copper (Cu), palladium (Pd), platinum (Pt), indium tin oxide Selected from the group consisting of oxide (IZO), aluminum zinc oxide (AZO), fluoro tin oxide (FTO), carbon nanotubes (CNT), graphene and polyethylene dioxythiophene: polystyrenesulfonate (PEDOT: PSS) And may include at least any one of them.

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.

An x-ray detector 100 according to an embodiment of the present invention includes an electron transport layer 120 formed on one side of a photoconductor layer 130. The X-ray detector 100 may include an electron transport layer 120 or a hole transport layer 140 on the other surface of the photoconductor layer 130 according to an embodiment of the present invention.

The X-ray detector 100 according to the first and second embodiments of the present invention includes an electron transport layer 150 on one side of the photoconductor layer 130 as in FIGS. 2A and 3A.

In addition, the X-ray detector 100 according to the third and fourth embodiments of the present invention includes the electron transport layer 150 on one side of the photoconductor layer 130 as shown in FIGS. 4A and 5A And a hole transport layer 150 on the other side of the photoconductor layer 130. [

The X-ray detector 100 according to the fifth embodiment of the present invention includes the electron transport layer 150 on one side of the photoconductor layer 130 as shown in FIG. 6A, And the electron transport layer 150 on the other surface.

An x-ray detector 100 according to an embodiment of the present invention includes a hole transport layer 160 formed on at least one side of a photoconductor layer 130.

The X-ray detector 100 according to the sixth and seventh embodiments of the present invention includes a hole transfer layer 150 on one side of the photoconductor layer 130 as shown in FIGS. 7A and 8A.

9A, the X-ray detector 100 according to the eighth embodiment of the present invention includes a hole transfer layer 150 on one side of the photoconductor layer 130, And the hole transport layer 150 is also provided on the other surface.

The electron transport layer 150 and the hole transport layer 160 according to the first to eighth embodiments of the present invention may include a material having a band gap energy greater than that of the photoconductor layer 130. [

That is, the work function of the electron transport layer 150 and the hole transport layer 160 may include a material that is smaller than the conduction band of the photoconductor layer 130 and larger than the valence band have.

Preferably, the electron transport layer 150 and the hole transport layer 160 may comprise a material that is 0.02 eV to 0.5 eV greater than the band gap energy of the photoconductor layer 130.

A barrier 170 is formed on both the upper and lower sides of the electron transport layer 150 and the hole transport layer 160 so that electrons or holes in the photoconductor layer 130 are not emitted to the first electrode (120) or the second electrode (140), so that no dark current is generated.

That is, in the X-ray detector 100 according to the embodiment of the present invention, the dark current is not generated, and the ratio of the photocurrent / dark current is increased to improve the resolution.

The electron transport layer 150 may include ZnO, Phenyl-C61-butyric acid methyl ester (PCBM), Al ₂ O ₃ (Aluminum Oxide), TiO ₂ (Titanium dioxide), mixtures thereof, .

The electron transporting layer 150 can 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 160 may be formed of at least one selected from the group consisting of NiO (Nickel oxide), CuI (Copper (I) iodide), CuSCN (Copper (I) thiocyanate), P3HT (Poly (3-hexylthiophene- Or a combination thereof.

The hole transport layer 160 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.

Hereinafter, the structural differences of the X-ray detectors according to the first to eighth embodiments will be described in detail by dividing the time when the light is not irradiated and the time when the light is irradiated through the movement of electrons and holes in the band offset structure .

FIG. 2A is a cross-sectional view of an X-ray detector according to a first embodiment of the present invention. Referring to FIG. 2A, the X-ray detector 100 according to the first embodiment includes an electron transfer layer 150 between the photoconductor layer 130 and the first electrode 120.

FIG. 2B shows an energy band diagram when no light is irradiated, and FIG. 2C shows an energy band diagram when light is irradiated.

2B, since the electron transporting layer 150 includes a material having a higher band gap energy than the photoconductor layer 130, a barrier 170 is formed at both the upper and lower portions of the electron transporting layer 150, When light is not irradiated, electrons and holes are prevented from moving to the first electrode 120, thereby reducing occurrence of a dark current.

As shown in FIG. 2C, when light is irradiated and an applied voltage is applied, the energy level of the first electrode 120 is lowered and the energy level of the second electrode 140 is raised. This causes the electrons in the photoconductor layer 130 to smoothly move to the first electrode 120 and the holes in the photoconductor layer 130 to block the movement of the first electrode 120, So that the photocurrent can be smoothly generated.

Therefore, in the X-ray detector according to the first embodiment of the present invention, when the light is not irradiated, the generation of the dark current is reduced, and when the light is irradiated, the photocurrent is generated and the ratio of the photocurrent / dark current increases. Can be implemented.

3A is a cross-sectional view of an X-ray detector according to a second embodiment of the present invention. 3A, the X-ray detector 100 according to the second embodiment includes an electron-transporting layer 150 between the photoconductor layer 130 and the second electrode 140.

FIG. 3B shows an energy band diagram when light is not irradiated, and FIG. 3C shows an energy band diagram when light is irradiated.

3B, since the electron transport layer 150 includes a material having a higher band gap energy than that of the photoconductor layer 130, a barrier 170 is formed at both the upper portion and the lower portion of the electron transport layer 150, When light is not irradiated, electrons and holes are prevented from moving to the second electrode 140, thereby reducing occurrence of a dark current.

As shown in FIG. 3C, when light is irradiated and an applied voltage is applied, the energy level of the first electrode 120 is lowered and the energy level of the second electrode 140 is raised. This causes the electrons in the photoconductor layer 130 to smoothly move to the first electrode 120 and the movement to the second electrode 140 to be blocked and the holes in the photoconductor layer 130 to reach the second electrode 140 ), So that the photocurrent can be smoothly generated.

Therefore, in the X-ray detector according to the second embodiment of the present invention, when the light is not irradiated, the generation of dark current is reduced, and when the light is irradiated, a photocurrent is generated and the ratio of photocurrent / dark current is increased. Can be implemented.

4A is a cross-sectional view of an X-ray detector according to a third embodiment of the present invention. Referring to FIG. 4A, the X-ray detector 100 according to the third embodiment has a structure in which the electron transfer layer 150 is present between the photoconductor layer 130 and the first electrode 120 and the hole transport layer 160 And is present between the photoconductor layer 130 and the second electrode 140.

FIG. 4B shows an energy band diagram when no light is irradiated, and FIG. 4C shows an energy band diagram when light is irradiated.

4B, the electron transport layer 150 and the hole transport layer 160 include a material having a higher band gap energy than the photoconductor layer 130, A barrier 170 is formed on both upper and lower sides of the first electrode 120 and the second electrode 140 to prevent electrons and holes from moving to the first electrode 120 and the second electrode 140, have.

As shown in FIG. 4C, when light is applied and an applied voltage is applied, the energy level of the first electrode 120 is lowered and the energy level of the second electrode 140 is raised.

This causes the electrons in the photoconductor layer 130 to move smoothly to the first electrode 120 and the movement to the second electrode 140 to be blocked and the holes in the photoconductor layer 130 to reach the first electrode 120, and moves to the second electrode 140, so that a photocurrent can smoothly be generated.

Therefore, in the X-ray detector according to the third embodiment of the present invention, no dark current is generated when no light is irradiated, and when the light is irradiated, a photocurrent is generated to increase the ratio of photocurrent / dark current, .

5A is a cross-sectional view of an X-ray detector according to a fourth embodiment of the present invention. 5A, the X-ray detector 100 according to the fourth embodiment has a structure in which the electron transfer layer 150 is present between the photoconductor layer 130 and the second electrode 140, and the hole transport layer 160 And is present between the photoconductor layer 130 and the first electrode 120.

FIG. 5B shows an energy band diagram when no light is irradiated, and FIG. 5C shows an energy band diagram when light is irradiated.

5B, the electron transport layer 150 and the hole transport layer 160 include a material having a higher band gap energy than the photoconductor layer 130, A barrier 170 is formed on the upper and lower portions of the first electrode 120 and the second electrode 140 to block electrons and holes from moving to the first electrode 120 and the second electrode 140 when no light is irradiated, have.

As shown in FIG. 5C, when light is applied and an applied voltage is applied, the energy level of the first electrode 120 is lowered and the energy level of the second electrode 140 is raised.

This causes the electrons in the photoconductor layer 130 to move smoothly to the first electrode 120 and the movement to the second electrode 140 to be blocked and the holes in the photoconductor layer 130 to reach the first electrode 120, and moves to the second electrode 140, so that the photocurrent can be smoothly generated.

Therefore, in the X-ray detector according to the fourth embodiment of the present invention, when no light is irradiated, a dark current is not generated. When light is irradiated, a photocurrent is generated and a ratio value of photocurrent / dark current is increased. .

6A is a cross-sectional view of an X-ray detector according to a fifth embodiment of the present invention. 6A, the X-ray detector 100 according to the fifth embodiment includes an electron transport layer 150 formed on the photoconductor layer 130 and the first electrode 120 and the photoconductor layer 130 and the second electrode 140).

FIG. 6B shows an energy band diagram when no light is irradiated, and FIG. 6C shows an energy band diagram when light is irradiated.

6B, since the electron transport layer 150 includes a material having a higher band gap energy than that of the photoconductor layer 130, a barrier 170 is formed at both the upper portion and the lower portion of the electron transport layer 150, When light is not irradiated, electrons and holes are prevented from moving to the first electrode 120 and the second electrode 140, so that a dark current may not be generated.

As shown in FIG. 6C, when light is irradiated and an applied voltage is applied, the energy level of the first electrode 120 is lowered and the energy level of the second electrode 140 is raised.

This causes the electrons in the photoconductor layer 130 to move smoothly to the first electrode 120 and the movement to the second electrode 140 to be blocked and the holes in the photoconductor layer 130 to reach the first electrode 120, and moves to the second electrode 140, so that the photocurrent can be smoothly generated.

Therefore, in the X-ray detector according to the fifth embodiment of the present invention, when no light is irradiated, a dark current is not generated, and when light is irradiated, a photocurrent is generated to increase the ratio of photocurrent / dark current, .

7A is a cross-sectional view of an X-ray detector according to a sixth embodiment of the present invention. Referring to FIG. 7A, the X-ray detector 100 according to the sixth embodiment includes a hole transport layer 160 between the photoconductor layer 130 and the first electrode 120.

FIG. 7B shows an energy band diagram when no light is irradiated, and FIG. 7C shows an energy band diagram when light is irradiated.

7B, since the hole transporting layer 160 includes a material having a higher band gap energy than the photoconductor layer 130, the barrier 170 is formed on both the upper and lower sides of the hole transporting layer 160, When light is not irradiated, electrons and holes are prevented from moving to the first electrode 120, thereby reducing occurrence of a dark current.

As shown in FIG. 7C, when light is irradiated and an applied voltage is applied, the energy level of the first electrode 120 is lowered and the energy level of the second electrode 140 is raised.

This causes the electrons in the photoconductor layer 130 to move smoothly to the first electrode 120 and the holes in the photoconductor layer 130 to block movement to the first electrode 120, 140) so that the photocurrent can smoothly occur.

Therefore, in the X-ray detector according to the sixth embodiment of the present invention, when the light is not irradiated, the generation of the dark current is reduced, and when the light is irradiated, the photocurrent is generated to increase the ratio of the photocurrent / dark current, Can be implemented.

8A is a cross-sectional view of an X-ray detector according to a seventh embodiment of the present invention. Referring to FIG. 8A, the X-ray detector 100 according to the seventh embodiment includes a hole transport layer 160 between the photoconductor layer 130 and the second electrode 140.

FIG. 8B shows an energy band diagram when light is not irradiated, and FIG. 8C shows an energy band diagram when light is irradiated.

8B, since the hole transport layer 160 includes a material having a higher band gap energy than that of the photoconductor layer 130, the barrier 170 is formed at both the upper and lower portions of the hole transport layer 160, When light is not irradiated, electrons and holes are prevented from moving to the second electrode 140, thereby reducing occurrence of a dark current.

As shown in FIG. 8C, when light is irradiated and an applied voltage is applied, the energy level of the first electrode 120 is lowered and the energy level of the second electrode 140 is raised.

The electrons in the photoconductor layer 130 move smoothly to the first electrode 120 and the movement to the second electrode 140 is blocked and the holes in the photoconductor layer 130 reach the second electrode 140, so that the photocurrent can smoothly occur.

Therefore, in the X-ray detector according to the seventh embodiment of the present invention, when the light is not irradiated, the occurrence of the dark current is reduced, and when the light is irradiated, the photocurrent is generated to increase the ratio of the photocurrent / dark current, Can be implemented.

9A is a cross-sectional view of an X-ray detector according to an eighth embodiment of the present invention. 9A, the X-ray detector 100 according to the eighth embodiment is configured such that a hole transport layer 160 is formed between the photoconductor layer 130 and the first electrode 120, the photoconductor layer 130, and the second electrode 140).

FIG. 9B shows an energy band diagram when no light is irradiated, and FIG. 9C shows an energy band diagram when light is irradiated.

9B, since the hole transporting layer 160 includes a material having a higher band gap energy than that of the photoconductor layer 130, the barrier 170 is formed at both the upper portion and the lower portion of the hole transporting layer 160, When light is not irradiated, electrons and holes are prevented from moving to the first electrode 120 and the second electrode 140, so that a dark current may not be generated.

As shown in FIG. 9C, when light is applied and an applied voltage is applied, the energy level of the first electrode 120 is lowered and the energy level of the second electrode 140 is raised.

This causes the electrons in the photoconductor layer 130 to move smoothly to the first electrode 120 and the movement to the second electrode 140 to be blocked and the holes in the photoconductor layer 130 to reach the first electrode 120, and moves to the second electrode 140, so that the photocurrent can be smoothly generated.

Therefore, in the X-ray detector according to the eighth embodiment of the present invention, when no light is irradiated, a dark current is not generated. When light is irradiated, a photocurrent is generated and a ratio value of photocurrent / dark current is increased. .

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.

10 shows an x-ray system including an x-ray detector according to an embodiment of the present invention.

FIG. 10 illustrates the use of the X-ray system according to the 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.

10, an X-ray system 200 includes an X-ray generator 210 for generating X-rays 211, an X-ray detector 220 for detecting X-rays 211, a driving unit 230 for driving the X- A data processing unit 240 for processing the X-ray detection voltage of the X-ray detector 220, a video signal output unit 250 for outputting a video output signal according to the X-ray detection voltage, and a display device 260).

The X-ray 211 generated in the X-ray generator 210 can be irradiated onto the region to be inspected 271 of the patient 270. The x-ray transmitted through the region to be inspected 271 of the patient 270 can be irradiated to the x-ray detector 220.

The X-ray generator 210 is a polychromatic system that 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 subject to be imaged and the use environment of the X- And the array density can be adjusted.

Also, the x-ray generator 210 may be one unit x-ray generator or a plurality of unit x-ray generators, or may be a gentry x-ray generator.

The x-ray generator 210 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 210 may be operated in a 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 220 can provide the X-ray detection voltage corresponding to the intensity of the provided X-ray 211 to the display device 260 via the data processing unit 240 and the video signal output unit 250.

The x-ray detector 220 may be an x-ray detector according to an embodiment of the present invention. The X-ray detector 220 has the same components as those of the X-ray detector described with reference to FIGS. 2A to 9C, so that detailed description of the components that are redundant will be omitted.

The display device 260 can display the x-ray image corresponding to the video signal in real time. For example, the display device 260 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.

FIG. 11 illustrates 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.

11, the X-ray diffraction (XRD) analyzer 300 includes an X-ray generator 320 for irradiating an X-ray and an X-ray detector 330 for detecting an X-ray reflected or diffracted against the inspected object 310 .

The subject 310 may be spaced apart from the x-ray detector 330 by a predetermined distance and the x-ray generator 320 and the x-ray detector 330 may be arranged to have a predetermined angle around the subject 310. However, the predetermined distance and angle may be changed according to the type of X-ray system and the use environment.

The X-ray generator 320 has the same components as those of the X-ray generator described with reference to FIG. 10, so a detailed description of the redundant components will be omitted.

The x-ray detector 330 may be an x-ray detector according to an embodiment of the present invention. The X-ray detector 330 has the same components as those of the X-ray detector described with reference to FIGS. 2A to 9C, so that detailed description of the redundant components will be omitted.

The X-ray diffraction (XRD) analyzer 300 includes the X-ray detector 330 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 300 recognizes an image of a local area by using the X-ray detector 330 according to an embodiment of the present invention to obtain a high resolution image through x- It can be used for analysis and can improve performance.

Also, the X-ray diffraction (XRD) analyzer 300 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 a non-destructive testing apparatus including an X-ray detector according to an embodiment of the present invention will be described with reference to FIG.

FIG. 12 illustrates 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. 10, 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 may be an x-ray detector according to an embodiment of the present invention. Since the X-ray detector has the same components as those of the X-ray detector described with reference to FIGS. 2A to 9C, the 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.

Also, 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 mammomo, because there is no bone, the tube voltage may be lowered. However, in the case of the chest, the tube voltage is large 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%.

The X-ray detector according to the embodiment of the present invention forms an electron transfer layer or a hole transfer layer on one or both surfaces of the photo-conductor layer in order to avoid dark current, thereby increasing the ratio of photocurrent / dark current to realize a high- .

In addition, the X-ray detector according to the embodiment of the present invention can realize a high-resolution image in various fields such as the nondestructive inspection apparatus as described above.

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, 220, 330: X-ray detector 10, 110:
20, 120: first electrode 30, 130: photoconductor layer
40, 140: second electrode 50, 150: electron transport layer
60, 160: hole transport layer 70, 170: barrier
200: X-ray system 210: X-ray generator
211: X-ray 230:
240: Data processing unit 250: Video signal output unit
260: display device 270: patient
271: part to be inspected 300: x-ray diffraction analyzer
310: subject 320: x-ray generator

Claims (26)

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 >
An electron transport layer formed on one side of the photoconductor layer,
Wherein a band gap energy of the electron transport layer is greater than a band gap energy of the photoconductor layer to have a band offset structure in which a barrier is formed between the photoconductor layer and the electron transport layer,
Wherein the photoconductor layer comprises perovskite nanocrystalline particles and a perovskite compound comprising an organic ligand formed on the surface of the perovskite nanocrystalline particles,
The organic ligand is an alkyl halide ligand having the structure of alkyl-G,
Wherein G is any one of fluorine (F), chlorine (Cl), bromine (Br) or iodine (I).
The method according to claim 1,
Wherein the band gap energy of the electron transport layer is greater than the band gap energy of the photoconductor layer by 0.02 eV to 0.5 eV.
The method according to claim 1,
And an electron transport layer or hole transport layer formed on the other surface of the photoconductor layer, wherein the band gap energy of the electron transport layer or the hole transport layer is greater than the band gap energy of the photoconductor layer.
The method of claim 3,
Wherein the band gap energy of the electron transport layer is greater than the band gap energy of the photoconductor layer by 0.02 eV to 0.5 eV.
The method of claim 3,
Wherein the band gap energy of the hole transport layer is greater than the band gap energy of the photoconductor layer by 0.02 eV to 0.5 eV.
The method according to claim 1,
The electron transport layer may include any one selected from the group consisting of ZnO (Zinc oxide), Phenyl-C61-butyric acid methyl ester (PCBM), Al ₂ O ₃ (Aluminum oxide), and TiO ₂ Features an x-ray detector.
The method of claim 3,
Wherein the hole transport layer is selected from the group consisting of NiO (Nickel oxide), CuI (Copper (I) iodide), CuSCN (Copper (I) thiocyanate), and P3HT (Poly (3-hexylthiophene-2,5-diyl) Ray detector.
The method according to claim 1,
Wherein the photoconductor layer comprises a perovskite compound represented by Formula 1 below.
[Chemical Formula 1]
AMX ₃
Wherein A is a monovalent cation, M is a divalent metal cation, and X is a monovalent anion.
The method according to claim 1,
Wherein the photoconductor layer comprises a perovskite compound represented by the following formula (2).
(2)
A ₃ M ₂ X ₉
Wherein A is a monovalent cation, M is a trivalent metal cation, and X is a monovalent anion.
The method according to claim 1,
Wherein the photoconductor layer comprises a perovskite compound represented by the following formula (3).
(3)
A ₃ MX ₆
Wherein A is a monovalent cation, M is a trivalent metal cation, and X is a monovalent anion.
The method according to claim 1,
Wherein the photoconductor layer comprises a perovskite compound represented by the following formula (4).
[Chemical Formula 4]
AM ₂ X ₇
Wherein A is a monovalent cation, M is a trivalent metal cation, and X is a monovalent anion.
The method according to claim 1,
Wherein the photoconductor layer comprises a perovskite compound represented by the following formula (5).
[Chemical Formula 5]
A ₂ A ' _n-1 M _n X _{3n + 1}
(Wherein A is a monovalent cation, A 'is a monovalent cation, M is a monovalent, divalent, trivalent or tetravalent metal cation, X is a monovalent anion, and n is at least one .)
The method according to claim 1,
Wherein the photoconductor layer comprises a perovskite compound of nanocrystalline particles.
The method according to claim 1,
The photoconductor layer is the x-ray detector comprising the at least one selected from the group consisting of _{CdTe, PbI 2, a-Se} , PbO, HgI 2 and BiI _3.
The method according to claim 1,
Wherein the photoconductor layer further comprises an organic binder.
The method according to claim 1,
Wherein the photoconductor layer further comprises an inorganic binder.
The method according to claim 1,
Wherein the thickness of the photoconductor layer ranges from 1 m to 1,000 m.
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,
Wherein the substrate is an array substrate comprising a complementary metal-oxide semiconductor (CMOS), a charge coupled device (CCD), or a thin film transistor (TFT).
The method according to claim 1,
Wherein the substrate comprises any one selected from the group consisting of glass, quartz, silicon, and plastic.
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 >
And a hole transport layer formed on at least one side of the photoconductor layer,
Wherein a band gap energy of the hole transport layer is greater than a band gap energy of the photoconductor layer to have a band offset structure in which a barrier is formed between the photoconductor layer and the hole transport layer,
Wherein the photoconductor layer comprises perovskite nanocrystalline particles and a perovskite compound comprising an organic ligand formed on the surface of the perovskite nanocrystalline particles,
The organic ligand is an alkyl halide ligand having the structure of alkyl-G,
Wherein G is any one of fluorine (F), chlorine (Cl), bromine (Br) or iodine (I).
23. The method of claim 22,
Wherein the band gap energy of the hole transport layer is greater than the band gap energy of the photoconductor layer by 0.02 eV to 0.5 eV.
An x-ray generator generating an x-ray;
An x-ray detector according to any one of claims 1 to 23 for detecting said x-ray;
A driving unit for driving the X-ray detector; And
A data processor for processing the X-ray detection voltage
. ≪ / RTI >
25. The method of claim 24,
Wherein the x-ray system is an x-ray diffraction analyzer (XRD).
25. The method of claim 24,
Wherein the x-ray system is a non-destructive inspection apparatus.

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