JP2019189721A - Near infrared light emitting phosphor, phosphor mixture, light emitter, and light emitting device - Google Patents

Abstract

An object of the present invention is to provide a new type of near-infrared light emitting phosphor exhibiting excellent light emission intensity. A near-infrared light emitting phosphor represented by the general formula ScBO3: Cr (Sc may be partially substituted with at least one element selected from rare earth elements and group 13 elements). A phosphor mixture containing the present near-infrared light-emitting phosphor, wherein Y3Al5O12: Ce phosphor, CaAlSiN3 phosphor, SrCaAlSiN3 phosphor, (Y, Lu, Gd) 3 (Ga, Al, Sc) 5 O12: Cr phosphor, (Ba, Sr) 2SiO4: Eu phosphor, (Ba, Sr) 3SiO5: Eu phosphor, (Lu, Y, Gd) 3Al5O12: Ce phosphor, La3Si6N11: Ce phosphor, and α-sialon phosphor. A phosphor mixture comprising at least one phosphor selected from the group consisting of: [Selection diagram] Fig. 1

Description

  The present invention relates to a phosphor that emits light in the near-infrared wavelength region, and more particularly, to a near-infrared light-emitting phosphor excellent in emission characteristics, a phosphor mixture using the same, a light-emitting element, and a light-emitting device.

A phosphor has excellent light emission characteristics and emits light with very low energy consumption. In particular, with the recent increase in social needs for power saving, there is a high need for replacement of existing lamps by taking advantage of the excellent energy saving properties of phosphors. Near-infrared light has high light permeability to a living body, and is expected to be applied to nondestructive measurement. Near-infrared broadband light sources are suitable for multivariate analysis and are expected to be applied to component analysis. In particular, a light source that combines a broad emission spectrum such as a phosphor rather than a combination of sharp emission such as an LED is strongly desired for a light source having a broad emission distribution.

  In order to realize such a lamp, phosphors in various wavelength regions having excellent light emission characteristics are necessary. Especially, for phosphors emitting in the near infrared wavelength region (near infrared emitting phosphors), Compared with phosphors in other wavelength regions, it cannot be said that the light emission characteristics are sufficient, and further a light emission characteristic is required.

Conventional near-infrared phosphors include InBO ₃ : Cr, Y ₃ Al ₅ O ₁₂ : Cr, Y ₃ Ga ₅ O ₁₂ : Cr, Gd ₃ Al ₅ O ₁₂ : Cr, Gd ₃ Ga ₅ O ₁₂ : Cr It has been reported that the excitation intensity at 254 nm did not change even when the concentration of chromium element contained in these phosphors was changed (see Non-Patent Document 1).

Proceedings of the 32nd Annual Meeting of the Illuminating Society of Japan (1999), p. 47

  However, conventional near-infrared light-emitting phosphors cannot be said to have sufficient light emission intensity compared to other light emission colors, and those having higher light emission intensity are required. Particularly in applications as lamps that emit light in a wide band, high power and sustained operation are required for phosphors at a high level, and strong light emission intensity is required.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a new type of near-infrared light-emitting phosphor that exhibits excellent emission intensity.

  As a result of diligent research, the present inventors have found that a phosphor having a new composition not conventionally known as a phosphor emits a peak of near-infrared light and derived the present invention. Furthermore, the present inventors have also found that a phosphor mixture containing the phosphor and a certain kind of other phosphor emits broad light over a wide range of near-infrared regions, and thus derived the present invention.

Thus, the near-infrared light emitting phosphor disclosed in the present application is represented by the general formula ScBO ₃ : Cr (a part of Sc may be substituted with at least one element selected from rare earth elements and Group 13 elements). Is done. Further, the phosphor mixture disclosed in the present application is a phosphor mixture containing the near-infrared light emitting phosphor, and includes a Y ₃ Al ₅ O ₁₂ : Ce phosphor, a CaAlSiN ₃ phosphor, a SrCaAlSiN ₃ phosphor, (Y, Lu, Gd) ₃ (Ga, Al, Sc) ₅ O ₁₂ : Cr phosphor, (Ba, Sr) ₂ SiO ₄ : Eu phosphor, (Ba, Sr) ₃ SiO ₅ : Eu phosphor, (Lu, Y , Gd) ₃ Al ₅ O ₁₂ : Ce phosphor, La ₃ Si ₆ N ₁₁ : Ce phosphor, and at least one phosphor selected from the group consisting of α-sialon phosphors. Moreover, the light emitting element disclosed in the present application includes the near infrared light emitting phosphor or the phosphor mixture. Moreover, the light-emitting device disclosed in the present application includes the near-infrared light-emitting phosphor or the phosphor mixture.

It is an X-ray-diffraction pattern of the fluorescent substance of Example 1 of this invention. It is the light emission characteristic obtained from the fluorescent substance of Example 1 of this invention. It is the light emission characteristic obtained from the fluorescent substance of Example 2 of this invention. It is the light emission characteristic obtained from the fluorescent substance mixture of Example 3 of this invention. It is the light emission characteristic obtained from the fluorescent substance mixture of Example 4 of this invention. It is the light emission characteristic obtained from the fluorescent substance mixture of Example 4 of this invention.

The near infrared light emitting phosphor according to the present invention is represented by the general formula ScBO ₃ : Cr. Note that a part of Sc constituting the near-infrared light emitting phosphor according to the present invention may be substituted with at least one element selected from a rare earth element and a Group 13 element. Such rare earth elements include Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy ( Dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), Lu (lutetium). Examples of the Group 13 element include B (boron), Al (aluminum), Ga (gallium), and In (indium).

  The excitation source is not particularly limited as long as it has a shorter wavelength than the near-infrared region, but preferably, an ultraviolet region having a wavelength of 200 nm to 380 nm, violet visible light having a wavelength of 380 to 450 nm, or blue visible light having a wavelength of 450 to 495 nm. Light, yellow visible light having a wavelength of 570 to 590 nm, and orange visible light having a wavelength of 590 to 620 nm. From this, for example, an ultraviolet light emitting phosphor or a blue light emitting phosphor can be used as an excitation source.

  The near-infrared light-emitting phosphor according to the present invention emits orange visible light to red visible light to near-infrared light having an emission spectrum with a high color rendering property having an emission peak at a wavelength of 550 nm to 950 nm by irradiation from this excitation source. . In addition, since the near-infrared light-emitting phosphor of the present invention has a light emission peak at the above-mentioned wavelength of 550 nm to 950 nm, the near-infrared defined by the near-infrared light-emitting phosphor of the present invention is a near infrared (750 nm to 1400 nm). Means a wavelength region mainly composed of, and includes orange visible light and red visible light.

  As described above, the near-infrared light emitting phosphor according to the present invention emits near-infrared light (750 nm to 1400 nm) including orange visible light and red visible light with high emission intensity, and is used for a light emitting element, a light emitting device, and the like. can do.

  As one mode of such a light emitting device according to the present invention, it can be configured to include a near infrared light emitting phosphor according to the present invention and a light emitting element that emits near ultraviolet light. When the near-infrared light emitting phosphor according to the present invention is irradiated with near-ultraviolet light from a light-emitting element that emits near-ultraviolet light, an apparatus that efficiently emits near-infrared light can be configured. Moreover, it can also utilize for the white light-emitting device as a white light source close | similar to sunlight by combining with another well-known fluorescent substance.

Furthermore, the present inventor has confirmed that broader (flat) near-infrared light emission is realized by mixing the near-infrared light-emitting phosphor according to the present invention with other specific phosphors. . For example, the near-infrared light emitting phosphor according to the present invention, a Y ₃ Al ₅ O ₁₂ : Ce phosphor, a CaAlSiN ₃ phosphor, and (Y, Lu, Gd) ₃ (Ga, Al, Sc) ₅ O ₁₂ : By configuring the phosphor mixture as a mixture with the Cr phosphor, a broader (flat) near-infrared light emission is realized (see Examples described later).

  As described above, the mechanism for producing excellent near-infrared light emission that has not been obtained in the past has not yet been elucidated in detail, but each constituent element of the near-infrared light-emitting phosphor according to the present invention is blended in an optimal balance. Therefore, it is presumed that a crystal structure is formed in which crystallinity is enhanced and excellent light emission characteristics are exhibited.

Such a near-infrared light emitting phosphor according to the present invention is represented by the general formula Sc _1-x BO ₃ : Cr _x (x is 0 <x <1). For example, Sc _0.99 BO ₃ : Cr _{0.01, Sc 0.95 BO 3: Cr} 0.05, Sc 0.9 BO 3: like _{Cr 0.1} and the like.

  The composition ratio of each constituent element represented by the above general formula is determined from the raw material molar composition ratio of the starting material. That is, the composition ratio x defined in the general formula represents the raw material molar composition ratio of Cr in the starting material. The composition ratio (1-x) defined in the above general formula represents the raw material molar composition ratio of Sc in the starting material.

  A method for synthesizing the near-infrared light emitting phosphor according to the present invention having such excellent characteristics is not particularly limited. For example, one or more of a Cr source, a Sc source, and a B source in a light emission center, It can be manufactured by uniformly mixing using a dry or wet method and firing it in a reducing atmosphere.

  For each of the raw material compounds, a near-infrared light-emitting phosphor having a desired constituent element can be obtained from a compound containing the constituent elements (for example, Cr, Sc, B) of the near-infrared light-emitting phosphor according to the present invention. When used in such a manner (so that the constituent elements do not leak), there is no particular limitation.

  As an example of such a raw material compound, oxides, carbonates, oxalates, sulfides, hydroxides, halides and the like containing constituent elements of the near-infrared light emitting phosphor can be used. For example, regarding chromium element (Cr) which is one of the constituent elements of the near-infrared light emitting phosphor, chromium oxide or the like can be used as one of the raw material compounds. When the near-infrared light emitting phosphor according to the present invention is manufactured, each raw material compound is heat-treated, so that the heat treatment finally leaves only the constituent elements from each raw material compound, and the raw material compound is an oxide, Regardless of whether it is a hydroxide or a carbide, the desired near-infrared light emitting phosphor according to the present invention is formed.

  The near-infrared light emitting phosphor according to the present invention thus obtained has the above-described excellent characteristics as such, but further, by mixing with other phosphors, a wider range of near-infrared phosphors. It can be used as a phosphor mixture that emits broad light over the infrared region.

As such a phosphor mixture according to the present invention, the above-described near-infrared light emitting phosphor ScBO ₃ : Cr (a part of Sc is substituted with at least one element selected from a rare earth element and a Group 13 element) Y ₃ Al ₅ O ₁₂ : Ce phosphor, CaAlSiN ₃ phosphor, SrCaAlSiN ₃ phosphor, (Y, Lu, Gd) ₃ (Ga, Al, Sc) ₅ O ₁₂ : Cr phosphor , (Ba, Sr) ₂ SiO ₄ : Eu phosphor, (Ba, Sr) ₃ SiO ₅ : Eu phosphor, (Lu, Y, Gd) ₃ Al ₅ O ₁₂ : Ce phosphor, La ₃ Si ₆ N ₁₁ : Ce phosphor and at least one phosphor selected from the group consisting of α-sialon phosphor.

Preferably, it includes a Y ₃ Al ₅ O ₁₂ : Ce phosphor and a (Y, Lu, Gd) ₃ (Ga, Al, Sc) ₅ O ₁₂ : Cr phosphor, which is a broader (flat) near Infrared emission is obtained. More preferably, it contains CaAlSiN ₃ phosphor and / or SrCaAlSiN ₃ phosphor, and broader (flat) near-infrared light emission can be obtained.

  In the phosphor mixture according to the present invention, the weight ratio of each phosphor to be mixed is not particularly limited.

  The phosphor mixture according to the present invention is a near-infrared ray (750 nm to 750 nm) including orange visible light and red visible light showing a broad (flat) emission spectrum having an emission peak at a wavelength of 550 nm to 950 nm by irradiation from the excitation source. 1400 nm) can be emitted with high emission intensity, and can be used for various light-emitting elements and light-emitting devices.

  In order to further clarify the features of the present invention, examples are shown below, but the present invention is not limited to these examples.

(Example 1)
As raw materials, Cr ₂ O ₃ , H ₃ BO ₃ , Sc ₂ O ₃ have a final Cr: Sc: B: O molar composition ratio of 0.01: 0.99: 1: 3, 0.05: 0.95: 1: 3, It weighed so that it might be set to 0.1: 0.9: 1: 3, and it mixed using the mortar. This mixture was placed in an alumina crucible and baked in an electric furnace at 1200 ° C. for 5 hours in the atmosphere. After the fired product was washed with water, dried, and classified, a near-infrared light emitting phosphor Sc _0.99 BO ₃ : Cr _0.01 , Sc _0.95 BO ₃ : Cr _0.05 , Sc _0.9 BO ₃ : Cr _0.1 corresponding to Example 1 was obtained. The X-ray diffraction pattern was measured using an X-ray diffractometer (XRD6100, manufactured by Shimadzu Corp.) with a CuKα ray as a radiation source. Luminescence characteristics were measured by excitation at a wavelength of 450 nm and excitation at 590 nm with a fluorescence spectrophotometer (FP6500, manufactured by JASCO). The X-ray diffraction pattern of the obtained phosphor is shown in FIG. From FIG. 1, it was confirmed that no heterogeneous phase was observed in the obtained phosphor, and high-quality crystals were formed.

  In addition, the emission characteristics of the obtained phosphor at a wavelength of 450 nm excitation and 590 nm excitation are shown in FIGS. 2 and 3, respectively. From the obtained results, light emission with extremely high light emission intensity was confirmed in the near infrared region.

(Example 2)
(Three kinds of phosphor mixture)
Hereinafter, the near-infrared light emitting phosphor ScBO ₃ : Cr obtained in Example 1 was mixed with other phosphors to obtain a phosphor mixture. In this example, three types of phosphors were mixed. That is, Y ₃ Al ₅ O ₁₂ : Ce phosphor: Y _2.9 Ga ₅ O ₁₂ : Cr _0.1 phosphor: near infrared light emitting phosphor ScBO ₃ : Cr is mixed at a weight ratio of 1: 4: 6. A phosphor mixture was obtained. FIG. 4 shows the measurement results of the emission characteristics of the obtained phosphor mixture by excitation with a wavelength of 450 nm.

  It was confirmed that the obtained phosphor mixture emits near-infrared light with a flat emission spectrum over a wide range of wavelengths from 550 nm to 850 nm.

(Example 3)
(Four kinds of phosphor mixture)
In this example, four types of phosphors were mixed. That is, by weight ratio, Y ₃ Al ₅ O ₁₂ : Ce phosphor: Y _2.9 Ga ₅ O ₁₂ : Cr _0.1 phosphor: CaAlSiN ₃ phosphor: near-infrared light emitting phosphor ScBO ₃ : Cr is 1: A phosphor mixture mixed at 4: 0.1: 6 was obtained. Further, in the same weight ratio, to obtain a phosphor mixture was mixed by changing the CaAlSiN ₃ phosphor SrCaAlSiN ₃ phosphor. With respect to the obtained phosphor mixture, the measurement results of the emission characteristics by excitation at a wavelength of 450 nm are shown in FIGS. 5 and 6, respectively.

It was confirmed that each of the obtained phosphor mixtures emitted near infrared rays with a flat emission spectrum over a wide range of wavelengths from 550 nm to 850 nm. All showed good light emission, and in particular, it was confirmed that the phosphor mixture using the CaAlSiN ₃ phosphor emitted light with higher emission intensity.

  From the obtained results, the phosphor mixture of each example emitted flat near infrared light having a high emission intensity that has never been seen. It can be used as a lamp for necessary multivariate analysis.

Claims (6)

A near-infrared light-emitting phosphor represented by the general formula ScBO ₃ : Cr (a part of Sc may be substituted with at least one element selected from a rare earth element and a Group 13 element). A phosphor mixture comprising the near-infrared light-emitting phosphor according to claim 1,
Y ₃ Al ₅ O ₁₂ : Ce phosphor, CaAlSiN ₃ phosphor, SrCaAlSiN ₃ phosphor, (Y, Lu, Gd) ₃ (Ga, Al, Sc) ₅ O ₁₂ : Cr phosphor, (Ba, Sr) ₂ SiO ₄ : Eu phosphor, (Ba, Sr) ₃ SiO ₅ : Eu phosphor, (Lu, Y, Gd) ₃ Al ₅ O ₁₂ : Ce phosphor, La ₃ Si ₆ N ₁₁ : Ce phosphor, and α A phosphor mixture characterized in that it comprises at least one phosphor selected from the group consisting of sialon phosphors. The phosphor mixture according to claim 2,
A phosphor mixture comprising Y ₃ Al ₅ O ₁₂ : Ce phosphor and (Y, Lu, Gd) ₃ (Ga, Al, Sc) ₅ O ₁₂ : Cr phosphor. The phosphor mixture according to claim 2,
A phosphor mixture comprising a CaAlSiN ₃ phosphor and / or a SrCaAlSiN ₃ phosphor. A near-infrared light-emitting phosphor according to claim 1 or a phosphor mixture according to any one of claims 2 to 4. A near-infrared light-emitting phosphor according to claim 1 or a phosphor mixture according to any one of claims 2 to 4.