Phosphor, scintillator, and radiation detector

Abstract

To provide a phosphor or scintillator that exhibits good crystallinity, is free from harmful elements, and has a favorable emission wavelength.SOLUTION: A phosphor contains a crystal phase represented by the following formula (1), wherein, when light having a wavelength of 350 nm is irradiated with, the emission spectrum has one or more emission peaks in the wavelength region of 475 nm or more. A3BxIy (1). (In formula (1), A, B, and I denote elements constituting the compound, I represents iodide, A contains one or more elements selected from K, Rb, and Cs, B contains at least Cu, and 1.5≤x≤2.5 and 4.0≤y≤6.0 are satisfied.)SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a phosphor, a scintillator, and a radiation detector.

Background Art

[0002] Radiation detection is utilized in various fields such as security, medicine, and resource exploration. For example, a radiation conversion element (hereinafter, also simply referred to as a "conversion element") that converts radiation into an electrical signal is arranged in an array, and by irradiating an object with radiation, when the absorption rate of radiation varies for each position of the object, it is utilized that the amount of radiation incident on each conversion element is different, and an image of the object is drawn based on the detected dose for each conversion element. Among these imaging diagnostic devices, as an example of a scintillator used for indirectly converting X-rays into visible light, there is a halide-based material such as CsI:Tl (Patent Document 1), but it contains Tl which is a harmful element. As another example, materials such as Gd2O2S activated with Pr, Ce, etc. (Non-Patent Document 1 ) can be mentioned. However, since Gd2O2S is usually operated in the form of a sintered body and is not a single crystal, a scintillator material with excellent light transmittance such as a single crystal is required.

[0003] As a candidate for a scintillator that does not contain harmful elements, Cs3Cu2I5 crystals have been reported (Patent Document 2, Non-Patent Document 2, Non-Patent Document 3). Since this material has good crystallinity, it is also suitable for the production of bulk single crystals, but it is known as a material that emits light efficiently in the blue color. On the other hand, the light reception sensitivity of a Si photodiode widely used in a photodetector for radiation detection is good on the longer wavelength side such as green rather than blue. Therefore, it emits light on the longer wavelength side than blue and is more suitable for the light detector used in radiation detection.

[0004] As a candidate for a scintillator that does not contain harmful elements, Cs3Cu2I5 crystals have been reported (Patent Document 2, Non-Patent Document 2, Non-Patent Document 3). Since this material has good crystallinity, it is also suitable for the production of bulk single crystals, but it is known as a material that emits light efficiently in the blue color. On the other hand, the light reception sensitivity of a Si photodiode widely used in a photodetector for radiation detection is good on the longer wavelength side such as green rather than blue. Therefore, it emits light on the longer wavelength side than blue and is more suitable for the light detector used in radiation detection. good on the longer wavelength side such as green rather than blue. Therefore, it emits light on the longer wavelength side than blue ​There is a demand for phosphors and radiation scintillator materials.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0006]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] In view of the problems of the above-described prior art, an object of the present invention is to provide a phosphor or a scintillator having good crystallinity, not containing harmful elements, and having a good emission wavelength.

Means for Solving the Problems

[0008] As a result of intensive studies in view of the above problems, the present inventors have found that the problems can be solved by using a compound having a specific composition and having an emission peak wavelength within a predetermined range, and have completed the present invention. That is, the present invention includes at least the following embodiments.

[0009] That is, the present invention includes at least the following embodiments. <1>: It contains a crystal phase represented by the following formula (1), and when irradiated with light having a wavelength of 350 nm, the emission spectrum has one or more emission peaks in a wavelength region of 475 nm or more. A phosphor. A3B x I y ···(1) (In the above formula (1), A, B, and I refer to the elements constituting the compound, I means iodine (Iodide), A contains one or more elements selected from the group consisting of K, Rb, and Cs, B contains at least Cu, x and y respectively represent the molar ratios of B and I (iodine) when A is 3.0, and each independently satisfies 1.5 ≦ x ≦ 2.5 and 4.0 ≦ y ≦ 6.0.) <2>: When irradiated with light having a wavelength of 305 nm, the emission spectrum has one or more emission peaks in a wavelength region of 475 nm or less. The phosphor according to <1>. <3>: The phosphor according to <1> or <2>, which contains a single crystal having a major axis of 1 cm or more. <4>: A scintillator that emits light when irradiated with X-rays. The phosphor according to any one of <1> to <3> described above. <5>: The phosphor according to any one of <1> to <4>, which further contains a crystal phase represented by the following formula (2). A1B I z I w ···(2) (In the above formula (2), A, B, and I refer to the elements constituting the compound, I means iodine (Iodide), A contains one or more elements selected from the group consisting of K, Rb, and Cs, B contains at least Cu, z and w respectively represent the molar ratios of B and I (iodine) when A is 1.0, and each independently satisfies 1.5 ≦ z ≦ 2.5 and 2.0 ≦ w ≦ 4.0.) <6>: Particles in which the maximum major axis of the crystal of the crystal phase represented by the formula (2) is 1.0 nm or less are included by 1 or more, and the phosphor according to <5>. <7>: A radiation detection element comprising the phosphor according to any one of <1> to <6> and a photodetector. <8>: A radiation imaging apparatus comprising the radiation detection element according to <7> and an image conversion unit that converts an electrical signal output from the photodetector into an image.

Advantages of the Invention

[0010] According to the present invention, a phosphor as well as a radiation scintillator and a radiation direct detection device using a material that does not contain harmful elements such as cadmium, lead, and thallium can be provided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 4A

Figure 4B

Figure 5

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail. It should be noted that the present invention is not limited by the following embodiments. It is not limited at all by the following embodiments.

[0013] In one embodiment of the present invention, it includes a crystal phase represented by the following formula (1), and the emission spectrum when irradiated with light having a wavelength of 350 nm has one or more emission peaks in a wavelength region of 475 nm or more. It is a phosphor. Hereinafter, the above phosphor may be referred to as "this phosphor". A3B x I y ···(1) (In the above formula (1), A, B, and I refer to elements constituting the compound. I means iodide, A contains one or more elements selected from the group consisting of K, Rb, and Cs, B contains at least Cu, x and y respectively represent the molar ratios of B and I (iodine) when A is 3.0, and each independently satisfies 1.5 ≦ x ≦ 2.5 and 4.0 ≦ y ≦ 6.0.)

[0014] The A element contains any one or more of K, Rb, and Cs, and preferably contains Cs. In an embodiment where A contains Cs, the proportion of Cs in the A element is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and particularly preferably Or it is 90 mol% or more, most preferably 100 mol%. The inclusion of element A as Cs stabilizes the crystal structure. Furthermore, by removing impurities and reducing crystal strain a transparent single crystal grain can be obtained, and scattering of radiation and the like can be prevented .

[0015] The B element usually contains Cu. The proportion of Cu in the B element is preferably 50 mol% or more more preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more, and most preferably 100 mol%. The inclusion of element B as Cu stabilizes the crystal structure. Furthermore, by removing impurities and reducing crystal strain a transparent single crystal grain can be obtained, and scattering of radiation and the like can be prevented . Also, B may contain an element other than Cu, and examples of the element other than Cu include monovalent gold metal elements

[0016] This phosphor contains I (iodine). In one embodiment, as long as the effects of the present invention are not impaired I may be partially substituted with another element, such as Cl or Br, etc., but the substitution ratio by the other element is usually 20 mol% or less, preferably 10 mol% or less, more preferably 5.0 mol% or less, and particularly preferably 1.0 mol% or less The inclusion of the phosphor with I (iodine) having a large atomic number stabilizes the crystal structure, and for example when using the phosphor as a scintillator excited by radiation, the radiation absorption yield of the whole material is improved

[0017] The above x and y are the molar ratios of B and I (iodine) when the molar ratio of A in the compound is 3 shows the relative molar ratio, and each independently, x is usually 1.5 or more, preferably 1.7 or more , more preferably 1.8 or more, usually 2.5 or less, preferably 2.3 or less, more preferably 2.2 or less, and y is usually 4.0 or more, preferably 4.3 or more, more preferably 4.7 or more, usually 6.0 or less, preferably 5.7 or less, more preferably 5.3 or less . When x and y are within the above ranges, the crystal structure is stabilized, and a scintillation material with uniform quality can be obtained. The composition of the crystal phase can be measured by conventional methods such as GD-MS and ICP-OES. Also, the crystal structure can be identified by using X-ray diffraction measurement (XRD).

[0018] This phosphor has one or more emission peaks in the wavelength region of 475 nm or more in the emission spectrum when irradiated with light having a wavelength of 350 nm. The above emission peak wavelength is preferably 480 nm or more, more preferably 490 nm or more and usually 700 nm or less, and may be 600 nm or less, 550 nm or less. By having an emission peak in the above wavelength region, a phosphor that exhibits a good emission color with high sensitivity of the photodetector can be obtained.

[0019] In one embodiment, this phosphor has one or more emission peaks in the wavelength region of 475 nm or less in the emission spectrum when irradiated with light having a wavelength of 305 nm. The above emission peak wavelength is preferably 460 nm or less and usually 350 nm or more and may be 375 nm or more, 400 nm or more. By having an emission peak in the above wavelength region, a phosphor that emits light of a desired emission color depending on the excitation method can be obtained.

[0020] ​​​​ The phosphor embodiments may be single crystals or polycrystals. In a preferred embodiment, the phosphor contains single crystals having a major axis of 1 mm or more, more preferably single crystals having a major axis of 1 cm or more. In addition, in one embodiment, the phosphor is a scintillator material that emits light upon irradiation with radiation. material.

[0021] In one embodiment, the phosphor is a phosphor that further contains a crystal phase represented by the following formula (2). That is. A1B z I w ···(2) (In the above formula (2), A, B, and I refer to elements constituting the compound. I means iodine (Iodide). A contains one or more elements selected from the group consisting of K, Rb, and Cs. B contains at least Cu. z and w respectively represent the molar ratios of B and I (iodine) when A is 1.0, and each independently satisfies 1.5 ≦ z ≦ 2.5 and 2.0 ≦ w ≦ 4.0.) In the formula (2), the A, B, and I elements may be the same as those in the formula (1). Same.

[0022] In the formula (2), z and w respectively represent the relative molar ratios of B and I (iodine) when the molar ratio of A in the compound is 1. Each independently, x is usually 1.5 or more , preferably 1.7 or more, more preferably 1.8 or more, usually 2.5 or less, preferably 2.3 or less, more preferably 2.2 or less, and y is usually 2.5 or more, preferably 2. 7 or more, more preferably 2.9 or more, usually 3.5 or less, preferably 3.3 or less, more preferably 3.1 or less. When z and w are within the above ranges, the crystal structure is stabilized, and a scintillator of uniform quality is obtained. The target material can be obtained. The composition of the crystal phase can be measured by conventional methods such as GD-MS and ICP-OES. Also, the crystal structure can be identified by using X-ray diffraction measurement (XRD).

[0023] In one embodiment, the phosphor contains one or more particles in which the maximum major axis length of the crystal of the crystal phase represented by the formula (2) is 1 .0 nm or less. By including such a minute crystal phase as described above, a phosphor with more prominent emission on the longer wavelength side may be obtained. There are cases.

[0024] In one embodiment, the present invention is a radiation detection element comprising the phosphor and a photodetector. There is. Also, in another embodiment, the present invention is a radiation imaging apparatus comprising the radiation detection element and an image conversion unit that converts an electrical signal output from the photodetector into an image. In the radiation detection element and the radiation imaging apparatus, other than the members described above, commercially available or known members can be arbitrarily used.

[0025] The method for obtaining the phosphor is not particularly limited, but it can be obtained, for example, by the following method. That is, the raw materials of each element are mixed so that the molar ratio of each element used for the crystal phase becomes equal to the target composition, and after stirring until no powder is observed in an environment of 10 °C or higher and 80 °C or lower, a saturated solution is prepared with an appropriate solvent, and the remaining powdery solid is filtered through a filter. The temperature during stirring is preferably 20 °C or higher, preferably 70 °C or lower, and more preferably 60 °C or lower.

[0026] In one embodiment, when mixing the raw materials, the amount of the B element is the target composition. Reduce it from the stoichiometric ratio, or change the stirring method during mixing of the inorganic powder and the temperature during standing By doing so, etc., the phosphor can be obtained more reliably.

[0027] The solvent is not particularly limited, but those in which the raw materials dissolve and the target product precipitates appropriately are preferred For example, when using the halides of elements A and B in the above formula (1), polar solvents such as alcohols can be used for the purpose of ensuring the solubility of the raw materials, and poor solvents such as acetone can also be used to promote the precipitation of the product. The solvent can be appropriately changed according to the raw materials and the target product, or mixed and used.

[0028] The raw materials of each element are not particularly limited, but it is preferable to use a compound composed of any of the elements A, B, and C because unnecessary elements can be excluded. For example, halides of A and B respectively are preferred. The higher the purity of the raw material, the better. Usually, it is 95 mol% or more, preferably 99 mol % or more.

[0029] The material of the filter used for filtration is preferably one with low reactivity. For example, resins such as polytetrafluoro ethylene (PTFE) can be used, but it is not limited thereto. The pore size of the filter is usually 5.0 μm or less, preferably 2.0 μm or less, more preferably 1.0 μm or less, even more preferably 0.6 μm or less. The lower limit is not particularly limited, but usually it is 0.1 μm or more.

[0030] After filtration, the filtered solution is crystallized and grown by the VSA method (Vapor Saturation of an Antisolvent). That is, the above-mentioned saturated solution is injected into a vial and covered with a perforated film, and then placed in a beaker filled with an appropriate solvent. Then After that, after covering the upper part of the beaker with a film, place it on a hot plate or the like at a temperature of 10°C or higher and 80°C or lower and let it stand for 24 hours or more to obtain single crystals with a minor axis of 1 mm or more. The solvent used here is preferably the same as the solvent used in the saturated solution in order to suppress changes in solubility. Also, for the same reason, the temperature during standing is preferably the same as that of the saturated solution. The film is preferably made of a non-reactive material, and for example, paraffin or the like can be used. The standing time is not particularly limited as long as the crystal phase has sufficiently grown, but it is preferably 36 hours or more, more preferably 48 hours or more. The gentler the crystal growth, the easier it is to obtain crystals with fewer defects, and in that case, more time is required for standing.

Examples

[0031] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.

[0032] [Example 1] <Production of Cs3Cu2I5 phosphor> To a mixed solvent with a volume ratio of dimethyl sulfoxide to methanol of 5:2, Sigma Aldrich-made CsI (purity 99.9%) was added at 1.88 mol / L and CuI (purity 99. 999%) was added to a concentration of 1.2125 mol / L, and then stirred at room temperature until the raw materials were dissolved. A Cs / Cu / I solution with a concentration of 0.63 mol / L in terms of Cs3Cu2I5 was prepared. In this solution, the target crystal phase has a composition of Cs:Cu:I = 3:2:5, while the concentration of Cu in the solution is 97% of the above stoichiometric ratio. It should be noted that ​​​​​く。 Acetone was added to this solution, and after stirring until it became thoroughly homogeneous, it was passed through a 0.45-μm PTF E filter to prepare a precipitation solution. A container containing the precipitation solution was placed inside a container containing acetone with a volume 10 times that of the precipitation solution, and a crystal growth container was prepared. The crystal growth container was placed in a thermostatic bath and held for 2 days, then taken out, and the crystals precipitated in the crystal growth container were taken out.

[0033] Next, the same procedure was repeated except that the taken-out crystals were placed in the precipitation solution, and the crystals precipitated in the crystal growth container were taken out. From the above procedure, the phosphor of Example 1 composed of single crystals was obtained.

[0034] Figure 1 is a photograph of the phosphor according to Example 1. From Figure 1, it can be seen that this phosphor is composed of single crystals, and the length of the minor axis is 13 mm and the length of the major axis is 22 mm. Note that Figure 1 shows the form of one single crystal, but this can also be pulverized using a mortar or the like to make it powdery.

[0035] The obtained single crystal was measured for its X-ray diffraction pattern using an X-ray diffractometer Empyrean (Cu tube) manufactured by Malvern Panalytical. The results obtained are shown in Figure 2. Also, from XR D analysis, the crystal structure of this single crystal belongs to the orthorhombic system of space group Pnma and showed an extremely good agreement with the Cs3Cu2I 5 crystal structure. It was found that the lattice constant a-axis is 10.17 ± 0.04 angstroms, the b-axis is 11.65 ± 0.05 angstroms, and the c-axis is 14.35 ± 0.06 angstroms. The molar ratio of each element in the raw materials during synthesis and the X-ray diffraction pattern of the obtained single crystal are Cs ​The diffraction pattern simulated from the 3Cu2I5 crystal structure showed excellent agreement. Therefore, the crystal structure of the phosphor according to Example 1 was considered to be the Cs3Cu2I5 structure.

[0036] <Observation of Luminescence Spectrum by Photoexcitation> The luminescence spectra were measured when the single crystal obtained in Example 1 was excited with light of various wavelengths. The wavelength of the excitation light used in each example, the peak wavelength and the full width at half maximum (FWHM) in the luminescence spectrum are shown in Table 1. Also, the luminescence spectra at each excitation wavelength are shown in FIGS. 3A to 3C. As can be seen from Table 1 and FIGS. 3A to 3C, the phosphor according to Example 1 shows an emission wavelength suitable for detection by a photodetector by selecting an appropriate excitation light, and it can be seen that the emission wavelength can be adjusted according to the purpose.

[0037]

Table 1

[0038] As can be seen from Table 1 and FIGS. 3A to 3C, the phosphor according to Example 1 shows an emission wavelength suitable for detection by a photodetector by selecting an appropriate excitation light, and it can be seen that the emission wavelength can be adjusted according to the purpose. This shows that the phosphor according to Example 1 shows an emission wavelength suitable for detection by a photodetector by selecting an appropriate excitation light, and it can be seen that the emission wavelength can be adjusted according to the purpose.

[0039] <Measurement of Fluorescence Decay Time> The single crystal of Example 1 was photoexcited using the third harmonic (wavelength 355 nm) and the fourth harmonic (wavelength 266 nm) pulsed light of a nanosecond YAG (yttrium aluminum garnet) pulsed laser, and the time-resolved spectrum of the emission was measured using a streak camera equipped with a spectroscope to obtain the time decay curve of each emission. When the maximum value of the observed emission intensity was set to 1, the time required for the emission intensity to decay from the time when the emission intensity was maximum to 1 / e was defined as the fluorescence decay time (Decay Time, DT). DT was plotted with the time on the horizontal axis and the emission intensity on the vertical axis for each time, and the least squares method was used for fitting. The single crystal of Example 1 was photoexcited using the third harmonic (wavelength 355 nm) and the fourth harmonic (wavelength 266 nm) pulsed light of a nanosecond YAG (yttrium aluminum garnet) pulsed laser, and the time-resolved spectrum of the emission was measured using a streak camera equipped with a spectroscope to obtain the time decay curve of each emission. When the maximum value of the observed emission intensity was set to 1, the time required for the emission intensity to decay from the time when the emission intensity was maximum to 1 / e was defined as the fluorescence decay time (Decay Time, DT). DT was plotted with the time on the horizontal axis and the emission intensity on the vertical axis for each time, and the least squares method was used for fitting. The single crystal of Example 1 was photoexcited using the third harmonic (wavelength 355 nm) and the fourth harmonic (wavelength 266 nm) pulsed light of a nanosecond YAG (yttrium aluminum garnet) pulsed laser, and the time-resolved spectrum of the emission was measured using a streak camera equipped with a spectroscope to obtain the time decay curve of each emission. When the maximum value of the observed emission intensity was set to 1, the time required for the emission intensity to decay from the time when the emission intensity was maximum to 1 / e was defined as the fluorescence decay time (Decay Time, DT). DT was plotted with the time on the horizontal axis and the emission intensity on the vertical axis for each time, and the least squares method was used for fitting. The single crystal of Example 1 was photoexcited using the third harmonic (wavelength 355 nm) and the fourth harmonic (wavelength 266 nm) pulsed light of a nanosecond YAG (yttrium aluminum garnet) pulsed laser, and the time-resolved spectrum of the emission was measured using a streak camera equipped with a spectroscope to obtain the time decay curve of each emission. When the maximum value of the observed emission intensity was set to 1, the time required for the emission intensity to decay from the time when the emission intensity was maximum to 1 / e was defined as the fluorescence decay time (Decay Time, DT). DT was plotted with the time on the horizontal axis and the emission intensity on the vertical axis for each time, and the least squares method was used for fitting. The single crystal of Example 1 was photoexcited using the third harmonic (wavelength 355 nm) and the fourth harmonic (wavelength 266 nm) pulsed light of a nanosecond YAG (yttrium aluminum garnet) pulsed laser, and the time-resolved spectrum of the emission was measured using a streak camera equipped with a spectroscope to obtain the time decay curve of each emission. When the maximum value of the observed emission intensity was set to 1, the time required for the emission intensity to decay from the time when the emission intensity was maximum to 1 / e was defined as the fluorescence decay time (Decay Time, DT). DT was plotted with the time on the horizontal axis and the emission intensity on the vertical axis for each time, and the least squares method was used for fitting. The single crystal of Example 1 was photoexcited using the third harmonic (wavelength 355 nm) and the fourth harmonic (wavelength 266 nm) pulsed light of a nanosecond YAG (yttrium aluminum garnet) pulsed laser, and the time-resolved spectrum of the emission was measured using a streak camera equipped with a spectroscope to obtain the time decay curve of each emission. When the maximum value of the observed emission intensity was set to 1, the time required for the emission intensity to decay from the time when the emission intensity was maximum to 1 / e was defined as the fluorescence decay time (Decay Time, DT). DT was plotted with the time on the horizontal axis and the emission intensity on the vertical axis for each time, and the least squares method was used for fitting. The single crystal of Example 1 was photoexcited using the third harmonic (wavelength 355 nm) and the fourth harmonic (wavelength 266 nm) pulsed light of a nanosecond YAG (yttrium aluminum garnet) pulsed laser, and the time-resolved spectrum of the emission was measured using a streak camera equipped with a spectroscope to obtain the time decay curve of each emission. When the maximum value of the observed emission intensity was set to 1, the time required for the emission intensity to decay from the time when the emission intensity was maximum to 1 / e was defined as the fluorescence decay time (Decay Time, DT). DT was plotted with the time on the horizontal axis and the emission intensity on the vertical axis for each time, and the least squares method was used for fitting.​​ It was obtained by tinging. The emission intensity over time when excited by pulsed light with wavelengths of 266 nm and 355 nm, with the vertical axis represented on a logarithmic scale, is shown in FIGS. 4A and 4B, respectively.

[0040] The phosphor according to Example 1 was excited with pulsed light having wavelengths of 266 nm and 355 nm. When excited with pulsed light having a wavelength of 2 66 nm, the fluorescence decay curve could be well reproduced by a two-component exponential function, and the DT of the fast lifetime component was about 270 ns, and the DT of the slow lifetime component was about 900 ns, which was in good agreement. On the other hand, the fluorescence decay curve when excited with pulsed light having a wavelength of 355 nm was reproduced by a one-component exponential function and was considered to be a single component. Also, the fluorescence decay time was found to be about 730 ns accumulated. That is, the phosphor according to Example 1 exhibits a fluorescence decay time of less than 1 μs, indicating that it is suitable, for example, for applications such as radiation detection.

[0041] <Observation of Luminescence by X-ray Excitation> The single crystal according to Example 1 was irradiated with X-rays under the conditions of Cu Kα characteristic X-rays (Cu tube, applied voltage 40 kV, current 50 mA), and the emission spectrum was observed using a USB2000+ small fiber spectrometer manufactured by Ocean Optics. The results are shown in FIG. 5. As shown in FIG. 5, the single crystal according to Example 1 has a wide emission band from a wavelength of 400 nm to 600 nm, and particularly has a strong emission peak at a wavelength of 475 nm or more, which is favorable for the light reception sensitivity of the photodetector. It can be seen that it is an emission band.

[0042] As described above, according to the present invention, a phosphor and a scintillator with good crystallinity, free of harmful elements, and having an emission wavelength favorable for the light reception sensitivity of the photodetector can be provided. It is possible. In addition, by using such a phosphor and a scintillator, a more sensitive radiation detection element and a radiation imaging device can be provided.

Claims

1. comprising a crystal phase represented by the following formula (1), when irradiated with light having a wavelength of 350 nm, the emission spectrum has one or more emission peaks in a wavelength region of 475 nm or more, a phosphor. A ３ B ｘ I ｙ ...(1) (In the above formula (1), A, B, and I refer to elements constituting the compound, I means iodine (Iodide), A contains one or more elements selected from the group consisting of K, Rb, and Cs, B contains at least Cu, x and y respectively represent the molar ratios of B and I (iodine) when A is 3.0, and each independently satisfies 1.5 ≦ x ≦ 2.5 and 4.0 ≦ y ≦ 6.0.)

2. when irradiated with light having a wavelength of 305 nm, the emission spectrum has one or more emission peaks in a wavelength region of 475 nm or less, the phosphor according to claim 1.

3. the phosphor according to claim 1 or 2, comprising a single crystal having a major axis of 1 cm or more.

4. a scintillator that emits light when irradiated with X-rays, the phosphor according to any one of claims 1 to 3.

5. further comprising a crystal phase represented by the following formula (2), the phosphor according to any one of claims 1 to 4. (In the above formula (2), A, B, and I refer to elements constituting the compound, A 1 B ｚ I ｗ ... (2) I means iodine (Iodide), A contains one or more elements selected from the group consisting of K, Rb, and Cs, B contains at least Cu, z and w respectively represent the molar ratios of B and I (iodine) when A is 1.0, and each independently satisfies 1.5 ≦ z ≦ 2.5 and 2.0 ≦ w ≦ 4.0.)

6. the phosphor according to claim 5, containing one or more particles having a maximum major axis of 1.0 nm or less of the crystal of the crystal phase represented by the above formula (2).

7. a radiation detector comprising the phosphor according to any one of claims 1 to 6 and a photodetector.

8. a radiation imaging device comprising the radiation detection element according to claim 7 and an image conversion unit that converts an electrical signal output from the photodetector into an image. ​ ​ ​ ​

Images