CN110387235A - Near-infrared light-emitting phosphor, phosphor mixture, light-emitting element, and light-emitting device - Google Patents

Abstract

The present invention provides a near-infrared light-emitting phosphor, a phosphor mixture, a light-emitting element and a light-emitting device, which are novel near-infrared light-emitting phosphors capable of emitting good light-emitting intensity. The near-infrared light-emitting phosphor is represented by the general formula ScBO ₃ :Cr, wherein a part of Sc may be substituted with at least one element selected from rare earth elements and Group 13 elements.

Description

Near-infrared light-emitting phosphor, phosphor mixture, light-emitting element, and light-emitting device

technical field

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

Background technique

Phosphors have good light-emitting properties, and at the same time emit light with very energy saving, and are therefore attracting attention from an environmental perspective. In particular, with the increase in social demands for power saving in recent years, there is a high demand for replacing existing lamps by utilizing the excellent energy-saving properties of phosphors. Near-infrared light has high light transmittance to living organisms, and its application in non-destructive measurement is expected. In addition, the near-infrared broadband light source is suitable for multivariate analysis, and its application in composition analysis is expected. In particular, for a light source having a light emission distribution in a broad band, it is strongly expected that a light source combining a broad light emission spectrum such as a phosphor can be obtained by combining with sharp light emission such as an LED.

In order to realize such a lamp, phosphors in various wavelength regions with excellent light-emitting properties are required. Most importantly, phosphors that emit light in the near-infrared wavelength region (near-infrared light-emitting phosphors) are different from phosphors in other wavelength regions. Compared with the light-emitting properties, it is not sufficient to say that the phosphors having excellent light-emitting properties are more demanded.

As conventional near-infrared light-emitting phosphors, 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 are known ₁₂ : Chromium-activated phosphors such as Cr, and it has been reported that the excitation intensity at 254 nm does not change even if the concentration of the chromium element contained in these phosphors is changed (see Non-Patent Document 1).

prior art literature

Non-patent literature

Non-patent literature 1: Proceedings of the 32nd National Congress of the Illuminating Society (2011) 47 pages

SUMMARY OF THE INVENTION

The problem to be solved by the invention

However, the conventional near-infrared light-emitting phosphors cannot be said to have sufficient light-emitting intensity compared with other light-emitting colors, and a phosphor having more excellent light-emitting intensity is required. In particular, it is used as a lamp that emits light in a wide band, and a high luminous intensity is necessary for the phosphor to require high power and continuous operation at a high level.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a novel near-infrared light-emitting phosphor exhibiting excellent emission intensity.

means of solving problems

As a result of repeated studies, the present inventors have found that a phosphor of a new composition, which is not known as a conventional phosphor, emits near-infrared rays with a high peak, and completed the present invention. Furthermore, the inventors found that a phosphor mixture containing this phosphor and other types of phosphors emits light widely in a wide near-infrared region, thereby completing the present invention.

Therefore, the near-infrared light-emitting phosphor disclosed in the present application is represented by the general formula ScBO ₃ :Cr, wherein a part of Sc may be substituted with at least one element selected from rare earth elements and Group 13 elements. In addition, the phosphor mixture disclosed in this application is a phosphor mixture containing the near-infrared light-emitting phosphor, and contains a phosphor mixture selected from the group consisting of Y ₃ Al ₅ O ₁₂ :Ce phosphor, CaAlSiN ₃ phosphor, SrCaAlSiN ₃ phosphor, (Y, Lu,Gd) ₃ (Ga,Al,Sc) _5O12 :Cr phosphor, (Ba,Sr _{) 2SiO4} :Eu phosphor, (Ba,Sr _{) 3SiO5} :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 of the group formed by the α-sialon phosphor. In addition, the light-emitting element disclosed in the present application includes the near-infrared light-emitting phosphor or the phosphor mixture. In addition, the light-emitting device disclosed in the present application includes the near-infrared light-emitting phosphor or the phosphor mixture.

Description of drawings

FIG. 1 is an X-ray diffraction pattern of the phosphor of Example 1 of the present invention.

FIG. 2 shows the light emission characteristics obtained from the phosphor of Example 1 of the present invention.

FIG. 3 shows the light emission characteristics obtained from the phosphor of Example 1 of the present invention.

FIG. 4 shows the light emission characteristics obtained from the phosphor mixture of Example 2 of the present invention.

Fig. 5 shows the light emission characteristics obtained from the phosphor mixture of Example 3 of the present invention.

FIG. 6 is a light emission characteristic obtained from the phosphor mixture of Example 3 of the present invention.

Detailed ways

The near-infrared light-emitting phosphor according to the present invention is represented by the general formula ScBO ₃ :Cr. It should be noted 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 rare earth elements and Group 13 elements. Examples of 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). Moreover, as a group 13 element, B (boron), Al (aluminum), Ga (gallium), and In (indium) are mentioned.

The excitation source is not particularly limited as long as it has a wavelength shorter than that in the near-infrared region. Preferably, an ultraviolet region with a wavelength of 200 to 380 nm, violet visible light with a wavelength of 380 to 450 nm, blue visible light with a wavelength of 450 to 495 nm, and a wavelength of 450 to 495 nm are used. Yellow visible light of 570-590nm, orange visible light of wavelength 590-620nm. Thus, 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 peak at a wavelength of 550 nm to 950 nm and exhibiting a high color rendering emission spectrum upon irradiation from an excitation source. It should be noted that the near-infrared light-emitting phosphor of the present invention has an emission peak at the wavelength of 550 nm to 950 nm, and the near-infrared light defined by the near-infrared light-emitting phosphor of the present invention is a wavelength region mainly composed of near infrared rays (750 nm to 1400 nm). , which also includes orange visible light and red visible light.

As described above, the near-infrared light-emitting phosphor of 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 can be used for light-emitting elements, light-emitting devices, and the like.

As an embodiment of such a light-emitting device according to the present invention, a near-infrared light-emitting phosphor according to the present invention and a light-emitting element that emits light in near-ultraviolet light may be included. According to the near-infrared light-emitting phosphor of the present invention, by irradiating near-ultraviolet light from a light-emitting element that emits near-ultraviolet light, it is possible to configure a device that emits near-infrared light efficiently. In addition, by combining with other known phosphors, it can be used as a white light emitting device as a white light source close to sunlight.

Further, the present inventors have confirmed that by mixing the near-infrared light-emitting phosphor according to the present invention with other specific phosphors, wider (flat) near-infrared light emission is achieved. For example, by constituting as the near-infrared light-emitting phosphor according to the present invention with Y ₃ Al ₅ O ₁₂ :Ce phosphor, CaAlSiN ₃ phosphor and (Y,Lu,Gd) ₃ (Ga,Al,Sc) ₅ O ₁₂ : A phosphor mixture of a mixture of Cr phosphors realizes wider (flat) near-infrared emission (refer to Examples described later).

As described above, the mechanism for producing excellent near-infrared light emission that has not been obtained so far has not been elucidated in detail, but it is presumed that the constituent elements of the near-infrared light-emitting phosphor according to the present invention are formulated in an optimum balance, thereby improving crystallinity , forming a crystalline structure that exhibits good light-emitting properties.

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 satisfies 0<x<1), and examples thereof include Sc _0.99 BO ₃ :Cr _0.01 and Sc _0.95 BO ₃ : Cr _0.05 , Sc _0.9 BO ₃ : Cr _0.1 , etc.

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

The method for synthesizing the near-infrared light-emitting phosphor according to the present invention having such excellent properties is not particularly limited. It is prepared by homogeneously mixing and firing in a reducing atmosphere.

For each of the raw material compounds, a compound containing the constituent elements (for example, Cr, Sc, B) of the near-infrared light-emitting phosphor according to the present invention can be used to obtain a near-infrared light-emitting phosphor (without constituent elements) of the desired constituent element. omission), there is no special restriction.

As an example of such a raw material compound, oxides, carbonates, oxalates, sulfides, hydroxides, halides, etc. containing the constituent elements of the near-infrared light-emitting phosphor can be used. For example, with respect to 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. In the production of the near-infrared light-emitting phosphor according to the present invention, each of the raw material compounds is subjected to heat treatment, and by this heat treatment, only constituent elements remain from the respective raw material compounds, regardless of whether the raw material compounds are oxides or hydroxides. Alternatively, carbide forms the near-infrared light-emitting phosphor contemplated by the present invention.

The thus-obtained near-infrared light-emitting phosphor according to the present invention has the above-mentioned excellent properties by itself, and further, by mixing with other phosphors, it can be used as a phosphor that emits light in a wider near-infrared region. Phosphor mixture.

As such a phosphor mixture according to the present invention, the above-mentioned near-infrared light-emitting phosphor ScBO ₃ :Cr (a part of Sc may be substituted with one element selected from rare earth elements and Group 13 elements), and at the same time, Selected from _Y3Al5O12 :Ce phosphor, _CaAlSiN3 phosphor, _SrCaAlSiN3 phosphor, (Y,Lu,Gd _{)3 (} Ga,Al, _{Sc ) 5O12} :Cr phosphor, (Ba,Sr ) ₂ SiO ₄ :Eu phosphor, (Ba,Sr) ₃ SiO ₅ :Eu phosphor, (Lu,Y,Gd) _{3Al 5} O ₁₂ :Ce phosphor, La ₃ Si ₆ N ₁₁ :Ce phosphor, and At least one phosphor in the group of α-Sialon phosphors.

Preferably, Y ₃ Al ₅ O ₁₂ :Ce phosphor and (Y,Lu,Gd) ₃ (Ga,Al,Sc) ₅ O ₁₂ :Cr phosphor are contained, resulting in broader (flat) near-infrared emission. More preferably, by containing CaAlSiN ₃ phosphor and/or SrCaAlSiN ₃ phosphor, further broad (flat) near-infrared emission can be obtained.

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

According to the phosphor mixture of the present invention, by irradiation from the excitation source, it exhibits a broad (flat) emission spectrum of light having an emission peak at a wavelength of 550 nm to 950 nm, and can exhibit high emission intensity in a range including orange visible light and red light. Near-infrared rays (750 nm to 1400 nm) of visible light emit light, and can be used as various light-emitting elements, light-emitting devices, and the like.

In order to clarify the characteristics of the present invention, examples are given below, but the present invention is not limited to these examples.

(Example 1)

As raw materials, weigh Cr ₂ O ₃ , H ₃ BO ₃ and Sc ₂ O ₃ , so that the final molar composition ratio of Cr:Sc:B:O is 0.01:0.99:1:3, 0.05:0.95:1: 3. 0.1:0.9:1:3, mix with a mortar. The mixture was put into a crucible made of alumina, and sintered at 1200° C. for 5 hours in the air with an electric furnace. After the sintered body was washed with water, dried and classified, the near-infrared light-emitting phosphors Sc _0.99 BO ₃ :Cr _0.01 , Sc _0.95 BO ₃ :Cr _0.05 , and Sc _0.9 BO ₃ :Cr _0.1 of Example 1 were obtained. The X-ray diffraction pattern was measured using an X-ray diffraction apparatus (XRD6100, manufactured by Shimadzu Corporation) whose radiation source was CuKα rays. The emission characteristics by excitation at wavelengths of 450 nm and excitation at 590 nm were measured by a spectrofluorophotometer (FP6500, manufactured by JASCO Corporation). The X-ray diffraction pattern of the obtained phosphor is shown in FIG. 1 . As can be seen from FIG. 1 , the existence of a different phase was not confirmed in the obtained phosphor, and it was confirmed that a high-quality crystal was formed.

In addition, the luminescence characteristics of the obtained phosphors excited by wavelengths of 450 nm and 590 nm are shown in FIG. 2 and FIG. 3 , respectively. From the obtained results, it was found that light was emitted with extremely high emission intensity in the near-infrared region.

(Example 2)

(mixture of 3 phosphors)

Next, the near-infrared light-emitting phosphor ScBO ₃ :Cr obtained in the above 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, and near-infrared light-emitting phosphor ScBO ₃ :Cr were mixed in a weight ratio of 1:4:6 to obtain fluorescence body mixture. FIG. 4 shows the measurement results of the emission characteristics of the obtained phosphor mixture excited at a wavelength of 450 nm.

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

(Example 3)

(mixture of 4 phosphors)

In this example, four 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, CaAlSiN ₃ phosphor and near-infrared light emitting phosphor ScBO ₃ :Cr were combined in a weight ratio of 1:4:0.1 : 6 and mixed to obtain a phosphor mixture. In addition, the CaAlSiN ₃ phosphor was mixed with the SrCaAlSiN ₃ phosphor instead of the SrCaAlSiN 3 phosphor at the same weight ratio to obtain a phosphor mixture. The measurement results of the emission characteristics of the obtained phosphor mixture with respect to excitation at a wavelength of 450 nm are shown in FIG. 5 and FIG. 6 , respectively.

It was confirmed that all of the obtained phosphor mixtures emit near-infrared rays with a flat emission spectrum in a wide range of wavelengths from 550 nm to 850 nm. It was confirmed that all of them exhibited favorable light emission, and in particular, the phosphor mixture using the CaAlSiN ₃ phosphor was confirmed to emit light with a higher light emission intensity.

As can be seen from the obtained results, the phosphor mixtures of the respective examples have unprecedentedly high luminous intensity and emit flat near-infrared rays. Therefore, as an example of their application, they can be used as a variety of variables that require light from visible to near-infrared. Analytical luminaires.

Claims (6)

1. A near-infrared light-emitting phosphor represented by the general formula ScBO ₃ :Cr, wherein part of Sc can be substituted with at least one element selected from rare earth elements and Group 13 elements. 2. A phosphor mixture, characterized in that it is a phosphor mixture containing the near-infrared light-emitting phosphor according to claim 1, and contains a phosphor selected from the group consisting of 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 : At least one phosphor of the group consisting of an Eu phosphor, a (Lu,Y,Gd) ₃ Al ₅ O ₁₂ :Ce phosphor, a La ₃ Si ₆ N ₁₁ :Ce phosphor, and an α-sialon phosphor. 3. The phosphor mixture according to claim 2, characterized in that it contains Y ₃ Al ₅ O ₁₂ :Ce phosphor and (Y,Lu,Gd) ₃ (Ga,Al,Sc) ₅ O ₁₂ :Cr phosphor body. 4 . The phosphor mixture according to claim 2 , comprising a CaAlSiN ₃ phosphor and/or a SrCaAlSiN ₃ phosphor. 5 . 5 . A light-emitting element comprising the near-infrared light-emitting phosphor according to claim 1 or the phosphor mixture according to any one of claims 2 to 4 . 6 . 6 . A light-emitting device comprising the near-infrared light-emitting phosphor according to claim 1 or the phosphor mixture according to any one of claims 2 to 4 . 7 .