JP6597058B2 - Luminescent material - Google Patents

Description

  The present invention relates to a light emitting material, and more particularly to a light emitting material capable of up-conversion light emission.

  A photoelectric conversion element refers to an element capable of converting photon energy into electrical energy (photoelectric conversion) through some physical phenomenon. A solar cell is a kind of photoelectric conversion element, and can efficiently convert light energy of sunlight into electric energy.

  For the solar cell, a semiconductor material that absorbs sunlight and generates carriers is used. The spectrum of sunlight is distributed over a wide wavelength range (from about 0.3 μm to about 3.0 μm) from ultraviolet to infrared. On the other hand, when the semiconductor material is irradiated with sunlight, light having a longer wavelength than the light absorption edge of the semiconductor material is not absorbed and thus does not contribute to photoelectric conversion. Therefore, in order to obtain high photoelectric conversion efficiency, it is preferable to use long wavelength light.

  One of the technologies that use long-wavelength light is the use of up-conversion light emission. Upconversion light emission refers to a phenomenon in which two long-wavelength photons are converted to one short-wavelength photon. In the case of a silicon solar cell, the light absorption edge is about 1.1 μm. On the other hand, Er ions, which are a kind of rare earth ions, are known to exhibit an upconversion phenomenon that absorbs light of 1.5 μm and emits light of 0.98 μm.

  The emission wavelength of Er ions is slightly shorter than the light absorption edge of silicon. Therefore, upconversion light emission by Er ions is suitable for combination with a silicon solar cell. Actually, power generation by irradiation with 1.5 μm light (not absorbed by silicon) is realized by combining an Er upconverter and a silicon solar cell (see Non-Patent Document 1).

  However, rare earth ions generally have a narrow absorption wavelength range. For example, in the case of Er ions, the absorption wavelength region is about 1.45 to 1.6 μm. Therefore, light in this wavelength range is absorbed and used for upconversion light emission. However, light having a wavelength shorter than 1.1 μm to 1.45 μm is not absorbed by either the Er ion or the silicon solar cell, and thus cannot use the energy.

A. Boccolini, et al., J. Appl. Phys. 114, 064904 (2013)

  The problem to be solved by the present invention is to provide a light emitting material exhibiting highly efficient upconversion light emission.

In order to solve the above problems, the luminescent material according to the present invention is:
An oxide containing Er;
Ni added to the oxide,
The oxide is an Er ₃ A ₃ B ₅ O ₁₂ garnet (A is one or more elements selected from the group consisting of Sc, Y, La, Gd, and Er, and B is Al, Ga, And any one or more elements selected from the group consisting of In.

When an oxide containing a lanthanoid element is irradiated with light having a predetermined wavelength, up-conversion light emission occurs. However, lanthanoid ions have a narrow absorption wavelength range.
On the other hand, when Ni is added to A ₃ B ₅ O ₁₂ garnet containing Er, the luminous efficiency of up-conversion emission is improved. This is probably because Ni absorbs light in a wavelength range that Er ions cannot absorb, and the Er ions are excited by the energy.

It is the energy level of Er ³⁺ ion (cited from Non-Patent Document 1). Er: Photoluminescence spectrum of BaY ₂ F ₈ (quoted from Non-Patent Document 1). It is an absorption spectrum of Er: BaY ₂ F ₈ (cited from Non-Patent Document 1). _{(Er 0.1 Y 0.9) 3 (} Ni 0.02 Ga 0.98) 5 O 12 ( Example 1), and a diffuse reflectance spectrum of _{(Er 0.1 Y 0.9) 3 Ga} 5 O 12 ( Comparative Example 1). (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 1), (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Bi _0.02 Ga _0.96 ) ₅ O ₁₂ (Example 2), and (Er _0.1 Y _0.9) is a photoluminescence spectrum of ₃ Ga ₅ O ₁₂ (Comparative example 1). (Er _0.1 Y _0.9) is a diagram showing the excitation light intensity dependence of the photoluminescence intensity of _{3 (Ni 0.02 Ga 0.98) 5} O 12 ( Example 1).

It is a photoluminescence spectrum of (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 3). It is a photoluminescence spectrum of (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 (Al _0.25 Ga _0.75 ) _0.98 ) ₅ O ₁₂ (Example 4). It is a photoluminescence spectrum of (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 (Al _0.5 Ga _0.5 ) _0.98 ) ₅ O ₁₂ (Example 5). It is a photoluminescence spectrum of (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 (In _0.25 Ga _0.75 ) _0.98 ) ₅ O ₁₂ (Example 6). It is a photoluminescence spectrum of (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 (In _0.5 Ga _0.5 ) _0.98 ) ₅ O ₁₂ (Example 7).

It is a photoluminescence spectrum of (Er _0.1 (Sc _0.25 Y _0.75 ) _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 8). It is a photoluminescence spectrum of (Er _0.1 (Sc _0.5 Y _0.5 ) _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 9). It is a photoluminescence spectrum of (Er _0.1 (La _0.25 Y _0.75 ) _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 10). It is a photoluminescence spectrum of (Er _0.1 (La _0.5 Y _0.5 ) _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 11). It is a photoluminescence spectrum of (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Zr _0.02 Ga _0.96 ) ₅ O ₁₂ (Example 12). It is a photoluminescence spectrum of (Er _0.1 Gd _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 13). It is a photoluminescence spectrum of (Er _0.1 Gd _0.9 ) ₃ (Ni _0.02 Zr _0.02 Ga _0.96 ) ₅ O ₁₂ (Example 14). It is a photoluminescence spectrum of (Er _0.1 Gd _0.9 ) ₃ (Ni _0.02 Ti _0.02 Ga _0.96 ) ₅ O ₁₂ (Example 15).

(Er _0.2 Gd _0.8 ) ₃ Ga ₅ O ₁₂ (Comparative Example 2), (Er _0.2 Gd _0.8 ) ₃ (Ni _0.001 Ga _0.999 ) ₅ O ₁₂ (Example 16), (Er _0.2 Gd _0.8 ) ₃ (Ni _0.002 Ga _0.998 ) ₅ O ₁₂ (Example 17) (Er _0.2 Gd _0.8 ) ₃ (Ni _0.005 Ga _0.995 ) ₅ O ₁₂ (Example 18) and (Er _0.2 Gd _0.8 ) ₃ (Ni _0.01 Ga _0.99 ) ₅ O ₁₂ It is a photoluminescence spectrum of (Example 19). It is a figure which shows Ni / (Ni + Ga) ratio dependence of PL intensity | strength and internal quantum efficiency (IQE).

Hereinafter, an embodiment of the present invention will be described in detail.
[1. Luminescent material]
The luminescent material according to the present invention is
An oxide containing Er;
Ni added to the oxide.

[1.1. Oxide]
In the present invention, the base material of the light emitting material is made of an oxide containing Er. Er ions contained in the oxide serve as the emission center of up-conversion emission. An oxide containing Er is suitable as a light-emitting material used in combination with a silicon solar cell because the emission wavelength is slightly shorter than the light absorption edge of silicon.

In the present invention, A ₃ B ₅ O ₁₂ garnet containing Er is used as the oxide containing Er. However, A is one or more elements selected from the group consisting of Sc, Y, La, Gd, and Er. B is one or more elements selected from the group consisting of Al, Ga, and In. The A ₃ B ₅ O ₁₂ garnet containing Er may contain only Er as the A-site element, or may contain Er and other elements.
Among oxides containing Er, A ₃ B ₅ O ₁₂ garnet containing Er (in particular, Y ₃ Ga ₅ O ₁₂ garnet and Gd ₃ Ga ₅ O ₁₂ garnet) shows high luminous efficiency. The kind and content of metal elements other than Er contained in A ₃ B ₅ O ₁₂ garnet are not particularly limited.

[1.2. Er]
In the A ₃ B ₅ O ₁₂ garnet, Er occupies the A site. The ratio of Er in the A site is not particularly limited, and it is preferable to select an optimal ratio according to the composition of the base oxide.

For example, when the A ₃ B ₅ O ₁₂ garnet is Y ₃ Ga ₅ O ₁₂ garnet or Gd ₃ Ga ₅ O ₁₂ garnet, the ratio of Er in the A site (= Er / (Er + Y) ratio, or Er / The larger the (Er + Gd) ratio), the higher the luminous efficiency. In order to obtain such an effect, the Er / (Er + Y) ratio or the Er / (Er + Gd) ratio is preferably more than zero. The Er / (Er + Y) ratio or Er / (Er + Gd) ratio is more preferably 0.05 or more, and still more preferably 0.1 or more.

  On the other hand, if the ratio of Er occupying the A site is excessive, the light emission efficiency is lowered. Therefore, the Er / (Er + Y) ratio or the Er / (Er + Gd) ratio is preferably 0.4 or less. The ratio of Er / (Er + Y) or Er / (Er + Gd) is more preferably 0.3 or less.

[1.3. Ni]
In the present invention, Ni is added to the oxide. Ni is considered to have a function as a sensitizer, that is, a function of absorbing light having a wavelength that cannot be absorbed by the lanthanoid ion and exciting the lanthanoid ion by its energy.
In the A ₃ B ₅ O ₁₂ garnet, Ni occupies the B site. The ratio of Ni in the B site is not particularly limited, and it is preferable to select an optimal ratio according to the composition of the base oxide.

For example, when the A ₃ B ₅ O ₁₂ garnet is Y ₃ Ga ₅ O ₁₂ garnet or Gd ₃ Ga ₅ O ₁₂ garnet, the proportion of Ni in the B site (= Ni / (Ni + Ga) ratio) increases. , Luminous efficiency is improved. In order to obtain such an effect, the Ni / (Ni + Ga) ratio is preferably more than zero. The Ni / (Ni + Ga) ratio is more preferably 0.001 or more.

  On the other hand, if the proportion of Ni in the B site is excessive, the luminous efficiency is rather lowered. Therefore, the Ni / (Ni + Ga) ratio is preferably 0.05 or less. The Ni / (Ni + Ga) ratio is more preferably 0.02 or less, still more preferably 0.01 or less, and still more preferably 0.003 or less.

[1.4. Other additive elements]
The light emitting material may contain an additive element other than Er and Ni. Other additive elements
(A) an element that promotes up-conversion luminescence by Er ions,
(B) an element not involved in up-conversion luminescence,
(C) It is roughly classified into elements that inhibit up-conversion luminescence.
Of these, the fewer additive elements that inhibit upconversion luminescence, the better.

An example of an element that promotes upconversion light emission is Bi. Bi has the effect of improving the luminous efficiency itself of upconversion luminescence by lanthanoid ions. Therefore, when Ni and Bi are combined, the light emission efficiency of the light emitting material is further improved.
In the A ₃ B ₅ O ₁₂ garnet, Bi occupies the B site together with Ni. The ratio of Bi and Ni in the B site is not particularly limited, and an optimal ratio can be selected according to the composition of the base oxide.

For example, when the A ₃ B ₅ O ₁₂ garnet containing Er is Y ₃ Ga ₅ O ₁₂ garnet containing both Ni and Bi, or Gd ₃ Ga ₅ O ₁₂ garnet, the ratio of Ni in the B site (= As the ratio of (Ni / (Ni + Bi + Ga)) increases, the luminous efficiency improves. In order to obtain such an effect, the Ni / (Ni + Bi + Ga) ratio is preferably more than zero. The Ni / (Ni + Bi + Ga) ratio is more preferably 0.001 or more.

  On the other hand, if the proportion of Ni in the B site is excessive, the luminous efficiency is rather lowered. Therefore, the Ni / (Ni + Bi + Ga) ratio is preferably 0.05 or less. The Ni / (Ni + Bi + Ga) ratio is more preferably 0.02 or less, still more preferably 0.01 or less, and still more preferably 0.003 or less.

Similarly, when the A ₃ B ₅ O ₁₂ garnet containing Er is Y ₃ Ga ₅ O ₁₂ garnet containing both Ni and Bi, or Gd ₃ Ga ₅ O ₁₂ garnet, the ratio of Bi in the B site ( == Bi / (Ni + Bi + Ga) ratio) increases, the light emission efficiency improves. In order to obtain such an effect, the Bi / (Ni + Bi + Ga) ratio is preferably more than zero. The Bi / (Ni + Bi + Ga) ratio is more preferably 0.005 or more.

On the other hand, if the ratio of Bi in the B site becomes excessive, the light emission efficiency is lowered. Therefore, the Bi / (Ni + Bi + Ga) ratio is preferably 0.05 or less. The Bi / (Ni + Bi + Ga) ratio is more preferably 0.02 or less.
In addition, when Ni is added to A ₃ B ₅ O ₁₂ garnet, Ni generally replaces the B site. However, if the B element is a trivalent ion (Y ₃ Ga ₅ O ₁₂ , Gd ₃ Ga ₅ O _12, etc.), the Ni ion becomes trivalent depending on the synthesis temperature and atmosphere, and up-conversion The effect of improving the light emission efficiency is reduced. In order to stabilize divalent Ni ions, an element that tends to be tetravalent such as Zr and Ti may be further added.

[2. Manufacturing method of luminescent material]
The light emitting material according to the present invention can be produced by various methods.
As a manufacturing method of the light emitting material, for example,
(A) A method of mixing a solution obtained by dissolving an organometallic compound in an organic solvent, volatilizing the solvent, and heating the solid content,
(B) a method of melting and solidifying an oxide compounded to have a target composition;
(C) A method of heating and solid-phase diffusing an oxide compounded to have a desired composition;
and so on.

[3. Action]
When a light emitting material made of an oxide containing a lanthanoid element is irradiated with light of a predetermined wavelength, up-conversion light emission occurs. However, conventional luminescent materials
(A) The luminous efficiency of upconversion light emission itself is relatively low.
(B) The wavelength range of light absorbed by the emission center is narrow.
There is a problem.
Therefore, high conversion efficiency cannot be obtained simply by combining a conventional photoelectric conversion element and a conventional light emitting material.

For example, the wavelength of light absorbed by Er ions is about 1.5 μm (see FIG. 3). Therefore, even if a silicon solar battery and a light emitting material containing Er ions are combined, light in the wavelength range of 1.1 to 1.5 μm cannot be used for photoelectric conversion.
On the other hand, when Ni is added to the oxide containing Er, the luminous efficiency of up-conversion emission is improved. This is presumably because Ni has an effect as a sensitizer. That is, it is considered that Ni absorbs light that cannot be absorbed by Er ions (and the semiconductor of the photoelectric conversion element), and the Er ions are excited by the energy. Therefore, when such a light emitting material and a photoelectric conversion element are combined, the conversion efficiency of the entire system is improved.

The light absorption edge of silicon is about 1.1 μm. On the other hand, Er ions absorb light of about 1.5 μm and emit light of about 0.98 μm (see FIGS. 1 and 2). Therefore, in a photoelectric conversion system that combines a silicon solar cell and a light-emitting material containing Er ions, light that cannot be absorbed by silicon can be used for photoelectric conversion.
However, since up-conversion light emission is a non-linear phenomenon, the light emission efficiency depends on the light intensity. In addition to the low luminous efficiency of up-conversion emission itself, the proportion of light with a wavelength of 1.5 μm contained in sunlight is small, so the effect of up-conversion emission on the conversion efficiency of the entire system is limited. .

On the other hand, when Bi is added to an oxide containing a lanthanoid element such as Er, the emission efficiency itself of up-conversion emission is improved. Therefore, when the light emitting material containing Ni and Bi and the photoelectric conversion element are combined, the conversion efficiency of the entire system is further improved.
Although details of the reason why the luminous efficiency of up-conversion light emission itself is improved by the addition of Bi are unclear, it is probably because the diffusion of atoms is promoted and as a result, the crystallinity is improved.

(Examples 1-15, Comparative Example 1)
[1. Preparation of sample]
[1.1. Examples 1-2, Comparative Example 1]
MOD materials for each element (manufactured by Kojundo Chemical Laboratory Co., Ltd.) were mixed at a predetermined ratio. This mixed solution was dropped into an evaporating dish heated to 300 ° C. to evaporate the solvent. Next, the solid content was heated in the atmosphere from room temperature to 950 ° C. at a temperature increase rate of 230 ° C./hr, held for 4 hours, and naturally cooled. Then, it heated again to 1050 degreeC with the temperature increase rate of 17 degrees C / min, hold | maintained for 4 hours, and allowed to cool naturally. The composition of each sample is as follows.

Example 1: (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂
Example 2: (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Bi _0.02 Ga _0.96 ) ₅ O ₁₂
Comparative Example 1: (Er _0.1 Y _0.9 ) ₃ Ga ₅ O ₁₂

[1.2. Examples 3 to 15]
MOD materials for each element (manufactured by Kojundo Chemical Laboratory Co., Ltd.) were mixed at a predetermined ratio. This mixed solution was dropped into an evaporating dish heated to 300 ° C. to evaporate the solvent. Next, the solid content was heated in the air from room temperature to 800 ° C. at a heating rate of 200 ° C./hr, and after reaching 800 ° C., it was naturally cooled immediately. Then, it heated again to 1200 degreeC with the temperature increase rate of 5 degree-C / min, hold | maintained for 8 hours, and was naturally cooled. The composition of each sample is as follows.

Example 3: (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂
Example 4: (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 (Al _0.25 Ga _0.75 ) _0.98 ) ₅ O ₁₂
Example _{5: (Er 0.1 Y 0.9)} 3 (Ni 0.02 (Al 0.5 Ga 0.5) 0.98) 5 O 12
Example 6: (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 (In _0.25 Ga _0.75 ) _0.98 ) ₅ O ₁₂
Example _{7: (Er 0.1 Y 0.9)} 3 (Ni 0.02 (In 0.5 Ga 0.5) 0.98) 5 O 12
Example _{8: (Er 0.1 (Sc 0.25} Y 0.75) 0.9) 3 (Ni 0.02 Ga 0.98) 5 O 12
Example 9: (Er _0.1 (Sc _0.5 Y _0.5 ) _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂
Example _{10: (Er 0.1 (La 0.25} Y 0.75) 0.9) 3 (Ni 0.02 Ga 0.98) 5 O 12
Example 11: (Er _0.1 (La _0.5 Y _0.5 ) _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂
Example _{12: (Er 0.1 Y 0.9)} 3 (Ni 0.02 Zr 0.02 Ga 0.96) 5 O 12
Example _{13: (Er 0.1 Gd 0.9)} 3 (Ni 0.02 Ga 0.98) 5 O 12
Example 14: (Er _0.1 Gd _0.9 ) ₃ (Ni _0.02 Zr _0.02 Ga _0.96 ) ₅ O ₁₂
Example _{15: (Er 0.1 Gd 0.9)} 3 (Ni 0.02 Ti 0.02 Ga 0.96) 5 O 12

[2. Test method and results]
The diffuse reflectance spectrum and the photoluminescence (PL) spectrum of the obtained powder sample were measured. A semiconductor laser with a wavelength of 1.3 μm was used as the excitation light for the PL measurement. FIG. 4 shows diffuse reflection spectra of (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 1) and (Er _0.1 Y _0.9 ) ₃ Ga ₅ O ₁₂ (Comparative Example 1). The wavelength resolution is about 2 nm. It is the influence of the measuring device that the reflectance exceeds 100% at some wavelengths.
5 shows (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 1), (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Bi _0.02 Ga _0.96 ) ₅ O ₁₂ (Example 2). ) And (Er _0.1 Y _0.9 ) ₃ Ga ₅ O ₁₂ (Comparative Example 1). The wavelength resolution is about 2 nm. In Comparative Example 1, a slight signal can be seen at a wavelength of 1020 nm or more due to the influence of the measuring apparatus.
FIG. 6 shows the excitation light intensity dependence of the PL intensity of (Er _0.1 Y _0.9 ) ₃ (Ni _0.02 Ga _0.98 ) ₅ O ₁₂ (Example 1). The vertical axis is a value normalized by the maximum value of the PL spectrum.
Furthermore, the PL spectra of the samples obtained in Examples 3 to 15 are shown in FIGS.

The following can be understood from FIGS.
(1) In Comparative Example 1 not containing Ni, light absorption other than that caused by Er and PL did not occur. In contrast, in Examples 1 to 15 to which Ni was added, light having a wavelength of 1 μm to 1.45 μm was absorbed, and light emission by 1.3 μm excitation was observed. The PL intensity was proportional to the square of the excitation light intensity.
(2) It is considered that excitation light having a wavelength of 1.3 μm was absorbed by Ni, and Er was excited by this energy, resulting in up-conversion light emission having a wavelength of 0.98 μm. From the dependence of the emission intensity on the excitation light intensity (FIG. 6), it can be seen that two photons having a wavelength of 1.3 μm were converted into one photon having a wavelength of 0.98 μm.

(3) In Example 2 to which Ni + Bi was added, the emission intensity by excitation of 1.3 μm was further increased as compared with Example 1. This is probably because the addition efficiency of Bi improved the luminous efficiency of up-conversion emission by Er ions.

(Examples 16 to 19, Comparative Example 2)
[1. Preparation of sample]
A sample was prepared in the same manner as in Example 1 except that the MOD material was mixed so as to have the following composition.
Comparative Example 2: (Er _0.2 Gd _0.8 ) ₃ Ga ₅ O ₁₂
Example 16: (Er _0.2 Gd _0.8 ) ₃ (Ni _0.001 Ga _0.999 ) ₅ O ₁₂
Example 17: (Er _0.2 Gd _0.8 ) ₃ (Ni _0.002 Ga _0.998 ) ₅ O ₁₂
Example 18: (Er _0.2 Gd _0.8 ) ₃ (Ni _0.005 Ga _0.995 ) ₅ O ₁₂
Example 19: (Er _0.2 Gd _0.8 ) ₃ (Ni _0.01 Ga _0.99 ) ₅ O ₁₂

[2. Test method and results]
In the same manner as in Example 1, the photoluminescence (PL) spectrum of the obtained powder sample was measured. Moreover, the approximate internal quantum efficiency (IQE) of the powder sample was calculated | required by dividing the obtained emitted light intensity by the addition amount of Ni.
FIG. 20 shows the PL spectrum of each powder sample. FIG. 21 shows the dependence of PL intensity and internal quantum efficiency (IQE) on the Ni / (Ni + Ga) ratio. In FIG. 21, the vertical axis is a value normalized by the maximum value of the PL spectrum or the maximum value of the internal quantum efficiency. 20 to 21, the following can be understood.

(1) In Comparative Example 2 containing no Ni, light absorption other than that caused by Er and PL did not occur. On the other hand, in Examples 16 to 20 to which Ni was added, light having a wavelength of 1 μm to 1.45 μm was absorbed, and light emission by 1.3 μm excitation was observed.
(2) The Ni / (Ni + Ga) ratio is preferably 0.001 to 0.01, and particularly 0.001 to 0.003 is effective.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  The light emitting material according to the present invention can be used for photoelectric conversion elements such as thin film solar cells, photoconductive cells, photodiodes, and phototransistors.

Claims (5)

An oxide containing Er;
Ni added to the oxide,
The oxide is an Er ₃ A ₃ B ₅ O ₁₂ garnet (A is one or more elements selected from the group consisting of Sc, Y, La, Gd, and Er, and B is Al, Ga, And any one or more elements selected from the group consisting of In.   An oxide containing Er;
  Ni added to the oxide;
  Bi added to the oxide
With
  The oxide includes A containing Er. _Three B _Five O ₁₂ Garnet (A is one or more elements selected from the group consisting of Sc, Y, La, Gd, and Er, and B is one or more elements selected from the group consisting of Al, Ga, and In. Luminescent material consisting of element. The luminescent material according to claim 1, wherein the oxide is Y ₃ Ga ₅ O ₁₂ garnet containing Er or Gd ₃ Ga ₅ O ₁₂ garnet. Er / (Er + Y) ratio or Er / (Er + Gd) ratio is more than 0 and 0.4 or less,
The luminescent material according to claim 3, wherein the Ni / (Ni + Ga) ratio is more than 0 and 0.05 or less. Ni / (Ni + Bi + Ga) ratio is more than 0 and 0.05 or less,
The luminescent material according to claim 3 or 4, wherein a Bi / (Ni + Bi + Ga) ratio is more than 0 and 0.05 or less.

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