KR20100110068A - Luminescent material and method of manufacturing the same - Google Patents

Abstract

PURPOSE: A luminescent material and a manufacturing method thereof are provided to secure the excellent stability and tolerance, and to mass produce the luminescent material by a high temperature thermal treating process. CONSTITUTION: A manufacturing method of a luminescent material marked with chemical formula 1: CaMoO_4:M, comprises the following steps: mixing calcium salt as a host material, molybdate, and lanthanide metal salt as an activator inside a reactor, and heating and stirring in 100~300deg C; high temperature thermal treating the mixture in 900~1,100 deg C to form luminescent powder; and pulverizing the luminescent powder.

Description

Luminescent material and method of manufacturing the same

The present invention relates to a light-emitting body and a method for manufacturing the same, in detail, one or two selected from the group consisting of calcium and molybdenum salts as host material and Nd ³⁺ , Yb ³⁺ and Er ³⁺ as active agent (M). The above-described lanthanide metal salt relates to a light-emitting body having an optical property which is excited by visible light and emits infrared light, and a manufacturing method thereof.

Some emitters contain lead as a host lattice component, for example, a molybdate luminescent material containing MoO ₄ ^2- as a central structure introduced in 1995. Bernhardt, HJ, Phys. Stat. Sol. (A), 91,643, 1985). PbMoO ₄ emits red light having a maximum emission peak of 620 nm under 360 nm excitation conditions at room temperature of about 20 ° C.

However, luminescence in molybdate is not only achieved by lead itself. In other words, the luminescence property in molybdate is not determined by the metal ion M ²⁺ (M ²⁺ MoO ₄ , where M ²⁺ can be replaced by Ca, Sr, Cd, Zn, Ba, Pb, etc.). . The reason for this is found to be a problem caused by the lack of O ^2- ions bound to the MoO ₄ ^2- ions which are the central structures. Nevertheless, since Pb ²⁺ ions stabilize the host lattice, it can exhibit good light emission characteristics.

As a similar example, crystal-containing tungstates (Ca, Pb) WO ₄ exhibit strong green luminescence with high quantum output of at least 75% (Blasse, G., Radiationless processes in luminescent materials, in Radiationless Processes) , Dibartolo, B., Ed.Plenum Press, New york, 1980, 287). PbWO ₄ emits blue color at 250 nm excitation, and PbWO ₄ has orange emission band at 313 nm excitation. This result can be caused by Schottky defects or impurity ions (Phosphor Handbook, edited under the Auspice f phosphor Research Society, CRC Press New York, 1998, S 205).

However, these emitters can only be used for short wavelength UV excitation. In other words, these emitters are not employed in fluorescent lamps because of their instability to chemical properties and temperature conditions.

On the other hand, it is well known that most luminescent materials and phosphors become unstable by water, moisture, water vapor or polar solvents.

For example, spinelle aluminates and orthorhombic or akermanite silicates are more sensitive to water, moisture, water vapor, or polar solvents because of their high basicity. Properties.

Meanwhile, among the molybdate emitters of the M ²⁺ MoO ₄ structure, CaMoO ₄ in which the metal ion M ²⁺ is substituted with Ca is a tetragonal crystal structure with a hardness of 3.5 to 3.8 (mohs hardness), a melting point of 965 ° C., and a refractive index. Is a fluorescent substance of 1.98 and is called calcium molybdate, Calcium molybdenum oxide, or powellite. Calcium molybdate is a microwave dielectric, which is another representation of a non-electrically insulator, and refers to a substance that creates an inductive dipole in response to an external electric field. Ferroelectrics with dielectric constants of several hundred times that of conventional dielectrics have a very high dielectric loss, a rapid change in dielectric constant with frequency, and too high temperature dependence of dielectric constants, making them unusable in the microwave region. Therefore, the microwave dielectric is made to differentiate from the ferroelectric, and the dielectric that can be used in the microwave region is called a microwave dielectric. Microwave dielectrics, unlike ferroelectrics, are dielectrics that are as small as dozens of dielectric constants and have hundreds of times less dielectric loss and dielectric constant temperature dependence.

Therefore, the calcium molybdate is used as a ceramic material for blocking fluorescence properties, cathode materials, host crystals for laser applications, and radiation waste.

On the other hand, in the known literature using the light emission characteristics of CaMoO ₄ discloses a phosphor incorporating Eu, Tb to CaMoO ₄ as a lanthanide metal (journal of solid state chemistry, volume 181, issue 4, april 2008, p 855 - 862 ).

Other publications also disclose phosphors in which Eu, Tb ions are introduced into CaMoO ₄ hosts (materials science and engineering: B, volume 145, issues 1-3, 20 december 2007, p 34-40). In the known literature, phosphors having Pb ions introduced into a host of CaMoO ₄ have been disclosed (Inorganic Chemistry Communications, Volume 7, Issue 3, March 2004, Pages 389).

On the other hand, in addition to the light emitters known in the prior art, examples of the light emitter and the light emitting wavelength which are excited by ultraviolet rays and emit visible light are Y ₂ SiO ₅ : Ce (415 nm), YVO ₄ : Eu (632 nm), Ba ₂ P ₂ O ₇ : Ti (500 nm), Zn ₂ SiO ₄ : Mn (520 nm), Y ₂ O ₂ S: Tb (544 nm), CaSiO ₃ : Mn, Pb (610 nm), La ₂ O ₂ S: Tb (548 nm), YVO ₄ : Dy (570 nm), KMgF ₃ : Mn (596 nm), and the like, and are related to the present invention. Examples of the light emitting body and the light emitting wavelength that are excited by visible light and emit infrared light include Gd ₂ O ₂ S: Er (1550 nm), NaYW ₂ O ₆ : Er (1550 nm), CaF ₂ : Er, Yb (980 nm, 1550 nm), and the like.

On the other hand, the light emitters exemplified above have low production yields and are difficult to coagulate, powder, etc. in handling, which causes problems in mass production. In addition, there is a difference between the luminous material produced by the present invention and the luminescence properties, and this difference is expected to be due to the difference in the morphology of the crystal lattice of the host material formed according to the production conditions and the lanthanide metal used as the activator. The content is not described.

The present invention is to solve the problems of the prior art as described above, the present invention is to be excited by the visible light to emit infrared light, to provide a light emitting body having a high luminous intensity and a method of manufacturing the same.

A detailed object of the present invention is to provide a high temperature using one or two or more lanthanide metal salts selected from the group consisting of calcium and molybdenum salts as host materials and Nd ³⁺ , Yb ³⁺ and Er ³⁺ as active agents (M). The present invention provides a light emitting body capable of mass production by heat treatment, high luminous intensity, excellent stability, and strong resistance, and a method of manufacturing the same.

In order to achieve the above object, in the present invention, one or two or more lanthanide metal salts selected from the group consisting of calcium and molybdenum salts as host materials and Nd ³⁺ , Yb ³⁺ and Er ³⁺ as active agents (M) By using the present invention, there is provided a light emitting body having an optical property that is excited by visible light and emits infrared light, and a method of manufacturing the same.

Hereinafter, the present invention will be described in more detail.

The present invention,

a) mixing one or two or more lanthanide metal salts selected from the group consisting of calcium and molybdenum salts as host materials and Nd ³⁺ , Yb ³⁺ and Er ³⁺ as an active agent (M) in a reactor; Heating and stirring at 300 ° C .;

b) thermally treating the mixture at 900 to 1100 ° C. to produce luminescent powder;

c) pulverizing the luminescent powder with a grinder;

It is a method of manufacturing a light emitter of the general formula (1) comprising a.

[Formula 1]

CaMoO ₄ : M

[In Formula 1, M is one or two or more lanthanide metal ions selected from the group consisting of Nd ³⁺ , Yb ³⁺ and Er ³⁺ .]

The manufacturing method is called thermal decomposition, and it is preferable to use calcium salt and molybdenum salt as the host material in order to have higher emission intensity.

The calcium salt and molybdenum salt are preferably in a molar ratio of 1: 1 to 1.2, more preferably in a molar ratio of 1: 1. When mixed in the molar ratio of the above range, it can have a high emission intensity characteristics.

The calcium salt is used by selecting one or two or more from the group consisting of Ca (NO ₃ ) ₂ , CaSO ₄ , Ca ₃ (PO ₄ ) ₂ , Ca (OH) ₂ , CaF ₂ , CaBr ₂ and CaI ₂ Preferably, Ca (NO ₃ ) ₂ is used.

The molybdenum salt is preferably used one or two or more selected from the group consisting of (NH ₄ ) ₆ Mo ₇ O ₂₄ , Na ₂ MoO ₄ and K ₂ Mo ₄ O ₁₃ , more preferably (NH ₄ ) ₆ Mo ₇ O ₂₄ or Na ₂ MoO ₄ is used alone or in combination.

The activator (M) is preferably one or two or more lanthanide metal salts selected from the group consisting of Nd ³⁺ , Yb ³⁺ and Er ³⁺ , and the emission wavelength of the lanthanide metal salt is Nd ^3+. Is around 880 nm, 1060 nm and 1330 nm, Yb ³⁺ is around 980 nm and Er ³⁺ is around 1550 nm. The host material and the active agent are preferably in a molar ratio of 1: 0.001 to 0.1, and may have a high emission intensity characteristic when mixed in the molar ratio of the above range.

In addition, the mixture of the host material and the active agent of step a) may be prepared by further adding an organic acid and water.

The organic acid is at least one monovalent acid or phthalic anhydride, maleic anhydride, isophthalic acid, adipic acid selected from the group consisting of acrylic acid, methacrylic acid, lauryl acid, linoleic acid, linolenic acid, oleic pelagonic acid and abietic acid One or two selected from at least one divalent acid selected from the group consisting of finic acid, tetrahydro phthalic anhydride, terephthalic acid, azelic acid, het acid, sebacic acid, fumaric acid, succinic acid, citric acid, diglyconic acid and dimeric acid It is preferable that it is the above, More preferably, citric acid is used.

When the organic acid is added, there is an advantage in that a uniform composition and powdering are easy because complex salts are formed.

The organic acid is preferably added in a molar ratio of 0.1 to 1.2 with respect to the host material, and when mixed in the molar ratio of the above range, there is an advantage that powdering is easy.

Heating and stirring at 100 to 300 ° C. in step a) is preferably carried out for 1 to 24 hours, and when carried out in the above temperature range, evaporates water to mix a mixture of host material and active agent. Can be concentrated.

The pyrolysis method is preferably a high temperature heat treatment of the mixture at 900 to 1100 ℃ in step b), it is preferably carried out for 1 to 4 hours at a temperature of 900 to 1100 ℃. When performed in the above temperature range, it is possible to obtain a homogeneous light emitter and a powder-type light emitter capable of mass production, and to increase the luminous efficiency of the light emitter.

In addition, an alkali metal salt may be further added as a flux during the mixing of the host material and the activator of step a), and after the step a), the method may further include washing and drying the mixture. Is carried out under the same conditions as the pyrolysis method. This preparation method is called a flux use method, and the mixture wash is preferably washed with distilled water, and the flux is preferably sodium salt, potassium salt, lithium salt or a mixed salt thereof, more preferably lithium salt is used. Will be.

The flux is preferably added in a molar ratio of 0.1 to 0.5 with respect to the host material, and when mixed in the molar ratio of the above range, more uniform particles can be obtained and there is an advantage of maintaining a high luminous intensity after grinding.

In addition, a) A solution is prepared by mixing calcium salt as host material, one or two or more lanthanide metal salts selected from the group consisting of Nd ³⁺ , Yb ³⁺ and Er ³⁺ as active agent (M) and water. Preparing a B solution by mixing molybdenum salt and water as a host material;

b) mixing the A solution and the B solution, and then heating and stirring at 100 to 300 ° C .;

c) thermally treating the mixture at 900 to 1100 ° C. to produce luminescent powder;

d) pulverizing the luminescent powder with a grinder;

It can be prepared a light emitter of the formula (1) comprising a.

[Formula 1]

CaMoO ₄ : M

[In Formula 1, M is one or two or more lanthanide metal ions selected from the group consisting of Nd ³⁺ , Yb ³⁺ and Er ³⁺ .]

After the step a), the mixture may be further filtered, washed, and dried to manufacture a light-emitting body, which is called a reflux method. The reflux method is prepared under the A solution and the B solution separately and mixed, and after the step a), the mixture is filtered, washed and dried, and is carried out under the same conditions as the pyrolysis method. Preferably, the mixture is washed with distilled water, and the solution B of step b) is prepared at pH 9 or more by further adding at least one strong base solution selected from the group consisting of sodium hydroxide, lithium hydroxide and potassium hydroxide. More preferably at pH 10 or higher using sodium hydroxide as a strong base solution. When the solution B is prepared at a pH of 9 or more, sufficient basicity can be obtained to effectively obtain a luminescent powder, and the yield is high.

In addition, when the reactor is used as a high pressure reactor in step b) of the reflux method, this manufacturing method is called a high pressure method, and the high pressure method mixes the A solution and the B solution in the high pressure reactor, and after the step a), the mixture It is carried out under the same conditions as the pyrolysis method except that further comprising the step of filtration, washing and drying. Preferably, the mixture is washed with distilled water, and the high pressure reaction conditions of the high pressure method are preferably reacted at 100 to 400 ° C. for 10 to 20 MPa for 1 to 24 hours. There is an advantage that the powdering of is easy and the reaction time can be shortened.

The light emitting body manufactured by the manufacturing method is excited by visible light (VIS) and is characterized in that it emits light in the infrared (IR), the color of the light emitting body itself is white, the light emitting body is an ink, a sensor, a signal or a sensing element Characterized in that used as.

The emitter represented by Formula 1 is characterized in that its color is white, is excited in visible light (VIS), and emits light in infrared (IR).

[Formula 1]

CaMoO ₄ : M

[In Formula 1, M is a lanthanide metal ion, which is used alone or in combination from the group consisting of Yb ³⁺ and Er ³⁺ .]

The light emitting body according to the present invention has its own color, which is excited by visible light and has an optical characteristic of emitting infrared light, and has a high luminescence intensity, excellent stability, strong resistance, and good printability. When mixed with the printing ink of the printed material there is an advantage that can be utilized in the forgery prevention and authenticity, and relates to a light emitting body that can be used as a sensor, a signal or a sensing element and its manufacturing method.

According to the present invention, various kinds of light emitters exhibiting characteristics of fluorescence or light emission in areas where excited energy is excited by excitation of a specific material using electromagnetic waves such as visible light, ultraviolet light, and infrared light. To manufacture and utilize, has the effect of providing an easy technique.

When the present invention will be described based on Examples, the present invention is not limited by the Examples.

Example 1

Pyrolysis

TABLE 1

Table 1 shows the reagents used in the pyrolysis method and the amount of addition. After mixing each raw material of Table 1 in the reactor, the water was blown at 100 ° C., concentrated, and heated and stirred while gradually warming to 200 ° C. . At this time, the organic acid citric acid (citric acid) is broken down and the bond is broken. The mixture is placed in an electric furnace and subjected to a high temperature heat treatment at 900 ° C. for 2 hours. Nd as an activator was tested by varying 1 mol%, 3 mol%, 5 mol% and 10 mol%, respectively.

The particles of the CaMoO ₄ : Nd composition were pulverized with a disk mill, and the particles were less than 3 millimeters in diameter. Infrared light emission characteristics due to visible light excitation of the light emitters were determined using a fluorescence spectrophotometer (Edinburgh, Model No. Excitation with 585 nm visible light resulted in light emission in the infrared region of 1,065 nm, and the highest luminescence intensity was obtained at 3 mol% of Nd ions.

[Example 2]

Pyrolysis

TABLE 2

Table 2 shows the reagents used in the pyrolysis method and the amount of Nd (NO ₃ ) ₃ 05H ₂ O added at 0.204 g (0.0006 mol), and another active agent, Yb (NO ₃ ) ₃ 5H ₂ O, was added. A light emitter was manufactured in the same manner as in Example 1, except that 0.269 g (0.0006 mol) was further added.

Exciting the light emitter with 585 nm visible light using a fluorescence spectrophotometer showed light emission wavelength in 980 nm light emission by Yb and 1,065 nm infrared light by Nd.

Example 3

Pyrolysis

[Table 3]

Table 3 shows the reagents used in the pyrolysis method and the amount of Nd (NO ₃ ) ₃ 05H ₂ O added at 0.204 g (0.0006 mol) and 0.164 g (0.0006 mol) more of another active agent ErCl ₃ . A light emitter was prepared in the same manner as in Example 1 except for adding.

Exciting the light emitter with 522 nm and 585 nm visible light using a fluorescence spectrophotometer showed light emission at 1,550 nm light emission by Er and 1,065 nm light emission by Nd.

Example 4

High pressure

[Table 4]

Table 4 shows the reagents used in the high pressure method and the amount of addition. A solution was prepared by mixing and stirring Nd (NO ₃ ) ₃ 05H ₂ O, Ca (NO ₃ ) ₂ 4H ₂ O, and water.

B solution was prepared by mixing (NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O and water in Table 4 and then adjusting the pH to 8 with NaOH (1 M) solution.

The solution A and solution B were added to a Teflon-coated high-pressure reactor, followed by mixing at 270 ° C. at 15 MPa for 24 hours. The mixture was filtered, washed with distilled water, dried at 105 ° C., placed in an electric furnace, heat treated at 200 ° C. for 1 hour, and then heated to 900 ° C. to undergo a high temperature heat treatment for 2 hours. Nd as an activator was tested by varying 1 mol%, 3 mol%, 5 mol% and 10 mol%, respectively.

When the light emitting powder prepared by CaMoO ₄ : Nd composition was pulverized by a disk mill, the particles were 5 millimeters or less, and the infrared light emitting characteristics of the prepared light emitting body were the same as in Example 1.

Example 5

Flux

TABLE 5

Table 5 shows the reagents used in the fluxing method and the amount of addition, after mixing each raw material of Table 5 in the reactor, put in an alumina container, and heated up to 270 ℃ for 10 hours in an electric furnace, isothermal for 5 hours Was maintained. The heat-treated luminescent powder is washed with distilled water, dried at 105 ° C., placed in an electric furnace, and subjected to high temperature heat treatment at 900 ° C. for 3 hours. Nd as an activator was tested by varying 1 mol%, 3 mol%, 5 mol% and 10 mol%, respectively.

When the light emitting powder prepared by CaMoO ₄ : Nd composition was pulverized with a disk mill, the particles were 3 millimeters or less, and the infrared light emitting characteristics of the prepared light emitting body were the same as in Example 1.

Example 6

Reflux method

TABLE 6

Table 6 shows the reagents used in the reflux method and the amount of addition. A solution was prepared by mixing and stirring Nd (NO ₃ ) ₃ 05H ₂ O, Ca (NO ₃ ) ₂ 4H ₂ O, and water.

B solution was prepared by mixing (NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O and water in Table 6 and then adjusting the pH to 8 with NaOH (1 M) solution.

The solution A and solution B were added to the reactor and mixed, followed by stirring at 100 ° C. for 24 hours. The mixture was filtered, washed with distilled water, dried at 105 ° C., placed in an electric furnace, heat treated at 200 ° C. for 1 hour, and then heated to 900 ° C. to undergo a high temperature heat treatment for 2 hours. Nd as an activator was tested by varying 1 mol%, 3 mol%, 5 mol% and 10 mol%, respectively.

When the light emitting powder prepared by CaMoO ₄ : Nd composition was pulverized by a disk mill, the particles were 5 millimeters or less, and the infrared light emitting characteristics of the prepared light emitting body were the same as in Example 1.

TABLE 7

Table 7 shows the luminescence intensity according to the concentration of the activator of Example 1, the highest luminescence intensity when the concentration of the activator is 3 mol%.

[Table 8]

Table 8 shows the luminescence intensity according to the manufacturing method, it was confirmed that the luminescence intensity of the luminescent material prepared in Example 4 is the highest, and the luminescence intensity of the luminescent material prepared in Example 5 is the lowest through FIG.

TABLE 9

Table 9 shows the average particle size according to the preparation method.

TABLE 10

Table 10 shows the luminescence intensity according to the temperature of the high temperature heat treatment process, when the heat treatment temperature is 900 ℃ through Figure 3, the luminescence intensity of the light emitter is the highest, when the heat treatment temperature is higher or lower than 900 ℃ of the light emitter It was confirmed that the emission intensity was also lowered.

1 shows excitation wavelengths and emission wavelengths of the light emitting bodies prepared in Examples 1 to 6. (red: excitation wavelength, blue: emission wavelength)

Figure 2 shows the intensity characteristics of the emission wavelength according to the manufacturing method.

(Orange: Example 1, Red: Example 6, Blue: Example 4, Lime green: Example 5)

Figure 3 shows the intensity characteristics of the emission wavelength according to the temperature during the high-temperature heat treatment process in the manufacturing method of Example 4. (orange: 500 ℃, red: 700 ℃, blue: 1100 ℃, light green: 900 ℃)

Claims (15)

a) mixing one or two or more lanthanide metal salts selected from the group consisting of calcium and molybdenum salts as host materials and Nd ³⁺ , Yb ³⁺ and Er ³⁺ as an active agent (M) in a reactor; Heating and stirring at 300 ° C .; b) thermally treating the mixture at 900 to 1100 ° C. to produce luminescent powder; c) pulverizing the luminescent powder with a grinder; Method for producing a light emitter of the general formula (1) comprising a. [Formula 1] CaMoO ₄ : M [In Formula 1, M is one or two or more lanthanide metal ions selected from the group consisting of Nd ³⁺ , Yb ³⁺ and Er ³⁺ .] The method of claim 1, The step a) is characterized in that the addition of the organic acid and water when the host material and the activator is mixed, wherein the organic acid is added to the host material in a molar ratio of 0.1 to 1.2 method of producing a light emitter. 3. The method of claim 2, The organic acid is at least one monovalent acid or phthalic anhydride, maleic anhydride, isophthalic acid, adipic acid selected from the group consisting of acrylic acid, methacrylic acid, lauryl acid, linoleic acid, linolenic acid, oleic pelagonic acid and abietic acid At least one divalent acid selected from the group consisting of pinic acid, tetrahydro phthalic anhydride, terephthalic acid, azelic acid, het acid, sebacic acid, fumaric acid, succinic acid, citric acid, diglyconic acid and dimeric acid Method for producing a light emitting body characterized in that. The method of claim 1, In the step a), the alkali metal salt is further added as a flux when the host material and the activator are mixed. The method of claim 4, wherein The flux is a sodium salt, potassium salt, lithium salt or a mixed salt thereof, the method for producing a light-emitting body characterized in that. The method of claim 5, The flux is a method of manufacturing a light emitter, characterized in that added in a molar ratio of 0.1 to 0.5 relative to the host material. a) A solution is prepared by mixing one or two or more lanthanide metal salts selected from the group consisting of calcium salt as host material, Nd ³⁺ , Yb ³⁺ and Er ³⁺ as active agent (M) and water, and a host Preparing a B solution by mixing molybdenum salt and water as a substance; b) mixing the A solution and the B solution, and then heating and stirring at 100 to 300 ° C .; c) thermally treating the mixture at 900 to 1100 ° C. to produce luminescent powder; d) pulverizing the luminescent powder with a grinder; Method for producing a light emitter of the general formula (1) comprising a. [Formula 1] CaMoO ₄ : M [In Formula 1, M is one or two or more lanthanide metal ions selected from the group consisting of Nd ³⁺ , Yb ³⁺ and Er ³⁺ .] The method of claim 7, wherein The solution B of step b) is prepared by adding at least one strong base solution selected from the group consisting of sodium hydroxide, lithium hydroxide and potassium hydroxide to prepare a pH 7 to pH 9. The method of claim 8, The reactor of step a) uses a high pressure reactor, the method of producing a light-emitting body, characterized in that for reacting for 1 to 24 hours at 10 to 20 MPa at 100 ℃ to 400 ℃. The calcium salt of any one of claims 1 to 9 is selected from Ca (NO ₃ ) ₂ , CaSO ₄ , Ca ₃ (PO ₄ ) ₂ , Ca (OH) ₂ , CaF ₂ , CaBr ₂ and CaI ₂ Method for producing a light-emitting body, characterized in that one or two or more selected from. Molybdenum salt of any one selected from claim 1 to 9 is characterized in that one or more selected from the group consisting of (NH ₄ ) ₆ Mo ₇ O ₂₄ , Na ₂ MoO ₄ and K ₂ Mo ₄ O ₁₃ . Method for producing a light emitting body. The method of manufacturing a light-emitting body, characterized in that the calcium salt and molybdenum salt of any one selected from claim 1 to 9 is a molar ratio of 1: 1 to 1.2. The method of manufacturing a light-emitting body according to any one of claims 1 to 9, wherein the host material and the active agent of any one of claims 1 to 9 have a molar ratio of 1: 0.001 to 0.1. Light emitter represented by the following formula (1). [Formula 1] CaMoO ₄ : M [In Formula 1, M is a lanthanide metal ion, which is used alone or in combination from the group consisting of Yb ³⁺ and Er ³⁺ .] 15. The method of claim 14, The light emitter is excited in the visible light (VIS), characterized in that the light emitting in the infrared (IR).

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