CN113698926A

CN113698926A - Narrow-band emission fluorescent powder and preparation method and application thereof

Info

Publication number: CN113698926A
Application number: CN202110693678.2A
Authority: CN
Inventors: 赵韦人; 杨焕鑫
Original assignee: Guangdong University of Technology
Current assignee: Guangdong University of Technology
Priority date: 2021-06-22
Filing date: 2021-06-22
Publication date: 2021-11-26

Abstract

The invention discloses narrow-band emission fluorescent powder and a preparation method and application thereof, belonging to the technical field of inorganic luminescent materials. The molecular formula of the narrow-band emission fluorescent powder is Al_2‑xGa_xO₃:yCr³⁺Wherein x is more than or equal to 0.1 and less than or equal to 0.3, and y is more than or equal to 0.005 and less than or equal to 0.05. The narrow-band emission fluorescent powder uses Cr³⁺The fluorescent powder can be effectively excited by near ultraviolet light as a luminescence center ion to realize narrow-band deep red light with high quantum efficiency, and the fluorescent powder presents a narrow-band deep red light emission peak with the maximum luminescence intensity at 693nm under the excitation of light near 405 nm; the full width at half maximum of the emission peak of the fluorescent powder is less than 5nm, narrow-band emission can be realized, and the response sensitivity is high. The fluorescent powder also has 48-100% of internal quantum efficiency and 28-57.4% of external quantum efficiency, and can be solvedThe problems of low imaging signal-to-noise ratio, low efficiency of lighting or display devices and the like are solved.

Description

Narrow-band emission fluorescent powder and preparation method and application thereof

Technical Field

The invention relates to the technical field of inorganic luminescent materials, in particular to narrow-band emission fluorescent powder and a preparation method and application thereof.

Background

The deep red light (about 650-750nm) band has good matching with the first biological window (650-950nm) due to its longer wavelength, and has a stronger penetrating power for biological tissues, and is often used as biological tissue imaging in recent years to assist medical observation and treatment. In portable health detection equipment for detecting blood oxygen saturation of living body, indirect detection of cardiopulmonary function, pressure and sleep quality, etc., an optical signal is often required to generate obvious response along with the change of a detected body, and a light source for generating the optical signal is required to have a narrow-band emission characteristic with high luminous efficiency to achieve the purpose. It is worth to say that besides deep red light, part of infrared light (750-1900nm) can also match with the biological window, but the detection device of this type of band is bulky and costly, and cannot meet the requirements of low cost, compactness and portability. Therefore, developing a fluorescent powder with high luminous efficiency and narrow-band emission becomes a key problem in the development of novel portable health detection equipment (such as a health bracelet, a watch, a portable blood pressure meter and the like).

Attempts to use Mn in the prior art⁴⁺To achieve deep red emission, however, due to Mn⁴⁺The self energy band structure characteristic, the half-height width of an emission peak is wider when the deep red light emission is realized by adjusting the lattice field strength, so that no way is available for realizing narrow-band emission, and the response sensitivity of the material is not high. Further, Mn having deep red light emission⁴⁺The excitation peak position of the LED is often near 330nm, the excitation peak position of the LED can not correspond to the emission peak position of the current commercial LED near ultraviolet (about 395nm) or blue light (about 450nm), the cost of the LED chip (such as 365, 280nm and the like) in the middle ultraviolet or deep ultraviolet region near 330nm is high, and the Mn is limited⁴⁺And (3) preparing the LED doped with the fluorescent powder. Therefore, the light source in the prior art has the problems that narrow-band deep red light emission cannot be realized, the full width at half maximum of an emission peak is wide, response sensitivity is low, the light source is difficult to correspond to the emission peak position of the current commercial LED chip, and luminous efficiency is low.

CN112552912A discloses a novel Cr³⁺The garnet-structure-doped broadband near-infrared fluorescent powder has the advantages that the full width at half maximum of an emission peak of the fluorescent powder is 100-300 nm, and the full width at half maximum is wide, so that the application of the fluorescent powder in the fields of high-color-gamut LEDs, medical health detection equipment with high response sensitivity requirements and the like is influenced; moreover, the luminescent efficiency of the fluorescent powder is low, the internal quantum efficiency is only 45-88%, and the low luminescent efficiency easily causes the problem of poor imaging signal-to-noise ratio.

Disclosure of Invention

The invention aims to solve the technical problems that the half-height width of an emission peak of the existing fluorescent powder is wider and the narrow-band deep red light emission cannot be realized, and provides the narrow-band emission fluorescent powder which can be excited by near ultraviolet light to realize the narrow-band deep red light with high luminous efficiency.

The invention aims to provide a narrow-band emission fluorescent powder.

The invention also aims to provide a preparation method of the narrow-band emission fluorescent powder.

Another object of the present invention is to provide a narrow-band emissive phosphor for use in the preparation of LED display devices, plant lighting devices, night vision devices and medical tissue imaging devices.

It is a further object of the present invention to provide a health monitoring device.

The above purpose of the invention is realized by the following technical scheme:

a narrow-band emitting fluorescent powder with the molecular formula of Al_2-xGa_xO₃:yCr³⁺Wherein x is more than or equal to 0.1 and less than or equal to 0.3, and y is more than or equal to 0.005 and less than or equal to 0.05.

For example, the narrow-band emitting phosphor is Al_1.9Ga_0.1O₃:0.005Cr³⁺(ii) a Or is Al_1.7Ga_0.3O₃:0.05Cr³⁺(ii) a Or is Al_1.8Ga_0.2O₃:0.02Cr³⁺(ii) a Or is Al_1.85Ga_0.15O₃:0.01Cr³⁺(ii) a Or is Al_1.75Ga_0.25O₃:0.03Cr³⁺。

Wherein, it is required to be noted that: narrow-band emission refers to narrow half-height width of an emission peak, which is the full width of the absorption band when the height at which the height of the absorption band is maximum is half, i.e., the width of the emission peak when the peak height is half.

Cr³⁺In a weaker latticeThe field will exhibit broadband emission with electron transitions in the form of⁴T₂→⁴A₂The substrate Al given in the invention_2-xGa_xO₃Is Cr³⁺Provides a stronger lattice field in which Cr is present³⁺Transition mode of²E→⁴A₂Such transitions exhibit narrower emission bands, i.e., narrower full widths at half maximum of the emission peak.

In the range of 0.1. ltoreq. x.ltoreq.0.3 with Ga³⁺The increase of the ion concentration and the decrease of the luminous intensity show the trend, the small range of the half-height width of the emission peak is increased, and the corresponding sensitivity is higher.

Within the range of y is more than or equal to 0.005 and less than or equal to 0.05, Cr³⁺The doping concentration is too low, and the luminous intensity of the fluorescent powder is lower; with Cr³ ⁺The half-height width of an emission peak is slightly increased by increasing the ion concentration, but the emission peak still has higher corresponding sensitivity, and the luminous intensity shows a trend of increasing and then decreasing. Cr (chromium) component³⁺The doping concentration is too high, agglomeration is easily caused, infrared light is emitted, and the luminous efficiency is reduced.

Preferably, the molecular formula of the phosphor is: al (Al)_2-xGa_xO₃:yCr³⁺Wherein x is more than or equal to 0.15 and less than or equal to 0.25, and y is more than or equal to 0.01 and less than or equal to 0.03.

Preferably, the molecular formula of the phosphor is: al (Al)_1.8Ga_0.2O₃:0.02Cr³⁺Or Al_1.85Ga_0.15O₃:0.01Cr³⁺Or Al_1.75Ga_0.25O₃:0.03Cr³⁺。

The invention also provides a preparation method of the narrow-band emission fluorescent powder, which comprises the following steps:

and uniformly mixing an aluminum-containing compound, a gallium-containing compound and a chromium-containing compound, and sintering to obtain the narrow-band emission fluorescent powder, wherein the sintering is to completely react at the temperature of 1400-1600 ℃. Too short sintering time can cause insufficient periodicity of lattice arrangement, and the obtained product has a large number of lattice defects, which can affect the luminous intensity of the fluorescent powder; however, too long sintering time also affects the lattice property of the material itself, and a small amount of impurities on the furnace wall can enter the lattice to act as a dopant, which affects the purity and the luminous efficiency of the prepared fluorescent powder.

Preferably, the sintering temperature is 1500-1580 ℃.

Preferably, the aluminium-containing compound is selected from one or more of aluminium oxide, aluminium hydroxide and aluminium carbonate.

Preferably, the gallium-containing compound is selected from one or more of gallium oxide and gallium hydroxide.

Preferably, the chromium-containing compound is selected from one or more of chromium oxide, chromium hydroxide and chromium carbonate.

Preferably, after sintering, the temperature is kept for 1-12 h. The heat preservation is to make the atoms of the reactant move fully to form the product of periodic lattice, so as to react fully and further obtain the narrow-band emission fluorescent powder with high luminous efficiency.

Preferably, the sintering is heating at a rate of 1-5 ℃/s.

Preferably, after sintering, the temperature is reduced at the speed of 1-5 ℃/s.

Preferably, the particle size of the narrow-band emission fluorescent powder is 0.5-1 μm. After cooling, the lumpy solid was ground to a powder for subsequent testing.

The invention also comprises the application of the narrow-band emission fluorescent powder in the preparation of LED display equipment, plant lighting equipment, night vision devices and medical tissue imaging equipment.

In the prior art, the LED display equipment has the requirement of high color gamut, and the fluorescent powder disclosed by the invention can be matched with the requirement of high color gamut, so that the problem of low color gamut value in the LED display equipment is solved.

In the prior art, the plant lighting equipment has the requirements of blue, dark red, infrared light sources and high brightness, and the fluorescent powder disclosed by the invention can be matched with the requirements of high brightness and dark red photosensitive pigments of plants, so that the problems of band mismatching and low light source brightness in the plant lighting equipment are solved.

In the prior art, a night vision device has high-precision requirements, and the fluorescent powder disclosed by the invention can be matched with the high-precision requirements achieved by narrow-band emission, so that the problem of low precision in the night vision device is solved.

In the prior art, the medical tissue imaging equipment has the requirement of light source brightness, and the fluorescent powder disclosed by the invention can be matched with the requirement of high brightness, so that the problem of imaging blur in the medical tissue imaging equipment is solved.

Preferably, the excitation wavelength of the narrow-band emission fluorescent powder in the application is 375-600 nm.

Preferably, the excitation wavelength of the narrow-band emitting phosphor in said application is 405 nm. The commercial LED near ultraviolet chip in the prior art has an emission peak of about 395nm, the fluorescent powder has the highest luminous intensity under the excitation of light of 405nm, and the emission peak positions of 405nm and 395nm are relatively close, so that the narrow-band emission fluorescent powder can be used as a light source to be correspondingly used with the commercial LED near ultraviolet chip in the prior art.

Preferably, the application temperature of the narrow-band emission fluorescent powder in the application is-268-300 ℃.

Further preferably, the application temperature of the narrow-band emission fluorescent powder is 0-300 ℃.

Still further preferably, the application temperature of the narrow-band emission fluorescent powder is 25-300 ℃.

The invention also provides health monitoring equipment, wherein a detection light source of the health monitoring equipment is prepared from the narrow-band emission fluorescent powder in any one of the specifications.

In the health monitoring equipment, the fluorescent powder is used as a detection material and is excited by near ultraviolet light to emit narrow-band deep red light with high quantum efficiency, the half-width height is small, narrow-band emission can be realized, the corresponding sensitivity is high, and the luminous efficiency is high. The fluorescent powder material can be used as a light source in portable health detection equipment, the light source irradiates on an arm or a finger, and a matched algorithm is formulated for accurate analysis by analyzing the tiny change of reflected light.

Compared with the prior art, the invention has the beneficial effects that:

the narrow-band emission fluorescent powder uses Cr³⁺The fluorescent powder can be effectively excited by near ultraviolet light as a luminescence center ion to realize narrow-band deep red light with high quantum efficiency, and the fluorescent powder presents a narrow-band deep red light emission peak with the maximum luminescence intensity at 693nm under the excitation of light near 405 nm; the full width at half maximum of the emission peak of the fluorescent powder is less than 5nm, narrow-band emission can be realized, and the response sensitivity is high.

The fluorescent powder also has 48-100% of internal quantum efficiency and 28-57.4% of external quantum efficiency, and can solve the problems of low imaging signal-to-noise ratio, low efficiency of lighting or display devices and the like.

In addition, the fluorescent powder has strong temperature stability, the luminous efficiency at the temperature of 150 ℃ is still more than 87% under the condition of room temperature, the luminous efficiency at the high temperature of 300 ℃ is more than 57% under the condition of room temperature, and the use requirements of high-power devices can be met.

Drawings

FIG. 1 is an XRD spectrum of the phosphor of example 1.

FIG. 2 is a fluorescence emission spectrum of the phosphor of example 1 under excitation of 405nm monochromatic light.

FIG. 3 shows fluorescence excitation spectrum of the phosphor of example 1 at a wavelength of 693 nm.

FIG. 4 is a scattergram of the quantum efficiency of the phosphor of example 1 as a function of temperature.

FIG. 5 is an XRD pattern of the phosphor of example 2.

FIG. 6 is a fluorescence emission spectrum of the phosphor of example 2 under excitation of 405nm monochromatic light.

FIG. 7 shows fluorescence excitation spectrum of the phosphor of example 2 at a wavelength of 693 nm.

FIG. 8 shows fluorescence excitation spectrum of the phosphor of example 2 at a wavelength of 772 nm.

FIG. 9 is a scatterplot of the quantum efficiency of the phosphor of example 2 as a function of temperature.

FIG. 10 is an XRD pattern of the phosphor of example 3.

FIG. 11 is a fluorescence emission spectrum of the phosphor of example 3 under excitation of 405nm monochromatic light.

FIG. 12 shows fluorescence excitation spectrum of the phosphor of example 3 at a wavelength of 693 nm.

FIG. 13 is a fluorescence excitation spectrum of the phosphor of example 3 at a wavelength of 772 nm.

FIG. 14 is a scatterplot of the quantum efficiency of the phosphor of example 3 as a function of temperature.

FIG. 15 is an XRD pattern of the phosphor of example 4.

FIG. 16 is a fluorescence emission spectrum of the phosphor of example 4 under excitation of 405nm monochromatic light.

FIG. 17 shows fluorescence excitation spectrum of the phosphor of example 4 at a wavelength of 693 nm.

FIG. 18 is a scatterplot of the quantum efficiency of the phosphor of example 4 as a function of temperature.

FIG. 19 is an XRD pattern of the phosphor of example 5.

FIG. 20 is a fluorescence emission spectrum of the phosphor of example 5 under excitation of 405nm monochromatic light.

FIG. 21 is a fluorescence excitation spectrum of the phosphor of example 5 at a wavelength of 693 nm.

FIG. 22 shows fluorescence excitation spectrum of the phosphor of example 5 at a wavelength of 772 nm.

FIG. 23 is a scatterplot of the quantum efficiency of the phosphor of example 5 as a function of temperature.

FIG. 24 is an XRD spectrum of the phosphor of comparative example 1.

FIG. 25 is a fluorescence emission spectrum of the phosphor of comparative example 1 under excitation of 405nm monochromatic light.

FIG. 26 is a fluorescence excitation spectrum of the phosphor of comparative example 1 at a wavelength of 693 nm.

FIG. 27 is a fluorescence excitation spectrum of the phosphor of comparative example 1 at a wavelength of 772 nm.

Fig. 28 is a scatter plot of quantum efficiency versus temperature for the phosphor of comparative example 1.

Fig. 29 is an XRD spectrum of the phosphor in comparative example 2.

FIG. 30 is a fluorescence emission spectrum of the phosphor of comparative example 2 under excitation of 405nm monochromatic light.

FIG. 31 is a fluorescence excitation spectrum of the phosphor of comparative example 2 at a wavelength of 693 nm.

Fig. 32 is a scatter plot of quantum efficiency versus temperature for the phosphor of comparative example 2.

Fig. 33 is an XRD spectrum of the phosphor in comparative example 3.

FIG. 34 is a fluorescence emission spectrum of the phosphor of comparative example 3 under excitation of 405nm monochromatic light.

FIG. 35 is a fluorescence excitation spectrum of the phosphor of comparative example 3 at a wavelength of 693 nm.

FIG. 36 is a fluorescence excitation spectrum of the phosphor of comparative example 3 at a wavelength of 772 nm.

Fig. 37 is a scatter plot of quantum efficiency versus temperature for the phosphor of comparative example 3.

Fig. 38 is an XRD spectrum of the phosphor in comparative example 4.

FIG. 39 is a fluorescence emission spectrum of the phosphor of comparative example 4 under excitation of 405nm monochromatic light.

FIG. 40 is a fluorescence excitation spectrum of the phosphor of comparative example 4 at a wavelength of 693nm to be monitored.

FIG. 41 is a scatterplot of quantum efficiency versus temperature for the phosphor of comparative example 4.

FIG. 42 is an XRD spectrum of the phosphor of comparative example 5.

FIG. 43 is a fluorescence emission spectrum of the phosphor in comparative example 5 under 437nm monochromatic light excitation.

FIG. 44 is a fluorescence excitation spectrum of the phosphor of comparative example 5 at a wavelength of 710 nm.

Detailed Description

The present invention will be further described with reference to specific embodiments, but the present invention is not limited to the examples in any way. The starting reagents employed in the examples of the present invention are, unless otherwise specified, those that are conventionally purchased.

Example 1

A narrow-band fluorescent powder with Al molecular formula_1.9Ga_0.1O₃:0.005Cr³⁺。

The preparation method comprises the following steps: using Al₂O₃，Ga₂O₃，Cr₂O₃According to the doping molar weight ratio of 1.9: 0.1: 0.005 is mixed in an agate mortar, fully ground for 20min until the mixture is uniform, poured into a ceramic crucible and put into a high-temperature furnace, the temperature is increased from room temperature to 1600 ℃ at the speed of 3 ℃/s and is maintained for 1h, then the temperature is reduced to the room temperature at the speed of 3 ℃/s, and a sample is taken out to the agate mortar and ground for about 5min to obtain the required fluorescent powder Al_1.9Ga_0.1O₃:0.005Cr³⁺。

Example 2

A narrow-band fluorescent powder with Al molecular formula_1.7Ga_0.3O₃:0.05Cr³⁺。

The preparation method comprises the following steps: using Al₂O₃，Ga₂O₃，Cr₂O₃According to the doping molar weight ratio of 1.7: 0.3: 0.05, mixing the mixture in an agate mortar, fully grinding for 20min until the mixture is uniform, pouring the mixture into a ceramic crucible, placing the ceramic crucible into a high-temperature furnace, heating the mixture from room temperature to 1400 ℃ at the speed of 3 ℃/s, maintaining the temperature for 12h, then cooling the mixture to the room temperature at the speed of 3 ℃/s, taking the sample out of the agate mortar, grinding for about 5min, and thus obtaining the required fluorescent powder Al_1.7Ga_0.3O₃:0.05Cr³⁺。

Example 3

A narrow-band fluorescent powder with Al molecular formula_1.8Ga_0.2O₃:0.02Cr³⁺。

The preparation method comprises the following steps: using Al₂O₃，Ga₂O₃，Cr₂O₃According to the doping molar weight ratio of 1.8: 0.2: 0.02, mixing the mixture in an agate mortar, fully grinding for 20min until the mixture is uniform, pouring the mixture into a ceramic crucible, placing the ceramic crucible in a high-temperature furnace, heating the mixture from room temperature to 1580 ℃ at the speed of 3 ℃/s, maintaining the temperature for 6h, then cooling the mixture to the room temperature at the speed of 3 ℃/s, taking the sample out of the agate mortar, grinding for about 5min, and thus obtaining the required fluorescent powder Al_1.8Ga_0.2O₃:0.02Cr³⁺。

Example 4

A narrow-band fluorescent powder with Al molecular formula_1.85Ga_0.15O₃:0.01Cr³⁺。

The preparation method comprises the following steps: using Al₂O₃，Ga₂O₃，Cr₂O₃According to the doping molar weight ratio of 1.85: 0.15: 0.01, mixing the mixture in an agate mortar, fully grinding for 20min until the mixture is uniform, pouring the mixture into a ceramic crucible, placing the ceramic crucible in a high-temperature furnace, heating the mixture from room temperature to 1500 ℃ at the speed of 3 ℃/s, maintaining the temperature for 6h, then cooling the mixture to the room temperature at the speed of 3 ℃/s, taking the sample out of the agate mortar, grinding for about 5min, and thus obtaining the required fluorescent powder Al_1.85Ga_0.15O₃:0.01Cr³⁺。

Example 5

A narrow-band fluorescent powder with Al molecular formula_1.75Ga_0.25O₃:0.03Cr³⁺。

The preparation method comprises the following steps: using Al₂O₃，Ga₂O₃，Cr₂O₃According to the doping molar weight ratio of 1.75: 0.25: 0.03 is mixed in an agate mortar, fully ground for 20min until the mixture is uniform, poured into a ceramic crucible and placed in a high-temperature furnace, the temperature is increased from room temperature to 1580 ℃ at the speed of 3 ℃/s and is maintained for 6h, then the temperature is reduced to room temperature at the speed of 3 ℃/s, a sample is taken out to the agate mortar and ground for about 5min, and the required fluorescent powder Al can be obtained_1.75Ga_0.25O₃:0.03Cr³⁺。

Comparative example 1

A fluorescent powder with molecular formula of Al_1.95Ga_0.05O₃:0.06Cr³⁺。

Comparative example 2

A fluorescent powder with molecular formula of Al_1.6Ga_0.4O₃:0.001Cr³⁺。

Comparative example 3

A fluorescent powder with molecular formula of Al_1.9Ga_0.1O₃:0.06Cr³⁺。

Comparative example 4

A fluorescent powder with molecular formula of Al_1.5Ga_0.5O₃:0.01Cr³⁺。

Comparative example 5

A deep red light emitting phosphor with a fluorescent molecular formula of Y₃Ga₅O₁₂:0.005Cr³⁺；

The preparation method comprises the following steps: using Y₂O₃，Ga₂O₃，Cr₂O₃According to the doping molar weight ratio of 3: 5: 0.005 is mixed in an agate mortar, fully ground for 20min till the mixture is uniform, poured into a ceramic crucible and put into a high-temperature furnace, the temperature is increased from room temperature to 1500 ℃ at the speed of 3 ℃/s and is maintained for 6h, then the temperature is reduced to the room temperature at the speed of 3 ℃/s, a sample is taken out to the agate mortar and ground for 5min, and the required fluorescent powder Y can be obtained₃Ga₅O₁₂:0.005Cr³⁺。

Characterization of

A Bruker X-ray diffractometer is adopted to test the crystal structure of a sample, a radiation source is a Cu target, the tube voltage is 50kV, the tube current is 60mA, the scanning step is 0.02, the scanning speed is 12 degrees/min, and the scanning range is 10 degrees to 90 degrees. The emission spectrum, the excitation spectrum and the variable-temperature fluorescence emission spectrum of the sample are obtained by testing through an FS-5 spectrometer, and the quantum efficiency is obtained by testing through a quantum efficiency measuring system QE-2100.

The external quantum efficiency refers to the number of emitted photons/the total number of photons of the light source, and in practical application, because the detector has certain signal noise, when the emitted signal is not strong enough, the noise can be greatly influenced on the result, if the emitted signal is strong, even if the noise of the instrument is large, the noise signal can be ignored, and therefore the luminescent material with high quantum efficiency can have a higher signal-to-noise ratio. The higher the external quantum efficiency of the phosphor, the better the performance.

FIG. 1 is an XRD pattern of the phosphor of example 1, and it can be seen from FIG. 1 that the product prepared by example 1 is Al_1.9Ga_0.1O₃:0.005Cr³⁺。

FIG. 2 is the fluorescence emission spectrum of the phosphor of example 1 under 405nm monochromatic light excitation, and it can be seen from FIG. 2 that Al is excited under 405nm monochromatic light excitation_1.9Ga_0.1O₃:0.005Cr³⁺Has a main emission peak position near 693nm and a full width at half maximum of about 3.6 nm. Under the excitation condition of 405nm, the internal and external quantum efficiencies of the quantum well are respectively tested to be 99.5 percent and 28.4 percent.

FIG. 3 shows the fluorescence excitation spectrum of the phosphor of example 1 at wavelength of 693nm, and it can be seen from FIG. 3 that two excitation bands can be seen when wavelength of 693nm is monitored, the excitation wavelength is 375-600 nm, and the excitation position with the highest intensity is near 405 nm.

FIG. 4 is a scattergram showing the change in quantum efficiency with temperature of the phosphor in example 1, and 98.85%, 95.17% and 77.28% of the quantum efficiency at room temperature can be maintained at 150, 200 and 300 ℃ respectively, whereby the external quantum efficiency at 200 ℃ can be obtained as 28.4% × 95.17% ≈ 27.0%.

FIG. 5 is an XRD pattern of the phosphor of example 2, and it can be seen from FIG. 5 that the product prepared by example 2 is Al_1.7Ga_0.3O₃:0.05Cr³⁺。

FIG. 6 shows the fluorescence emission spectrum of the phosphor of example 2 excited by 405nm monochromatic light, and Al can be seen from FIG. 6_1.7Ga_0.3O₃:0.05Cr³⁺Has a main emission peak position near 693nm and a full width at half maximum of about 4.6nm, and further has a near infrared broad-peak emission near 772 nm. Under the excitation condition of 405nm, the internal and external quantum efficiencies of the fluorescent powder are respectively tested to be 48.0 percent and 28.0 percent.

FIG. 7 shows the fluorescence excitation spectrum of the phosphor of example 2 at a wavelength of 693nm, from which FIG. 7 can be seen two excitation bands, the excitation wavelength is 375-600 nm, and the excitation position with the highest intensity is near 405 nm.

FIG. 8 shows the fluorescence excitation spectrum of the phosphor of example 2 at a wavelength of 772nm, and from FIG. 8, two excitation bands can be seen, and the excitation position with the highest intensity is still near 405 nm.

FIG. 9 is a scattergram showing the change in quantum efficiency with temperature of the phosphor in example 2, and 87.41%, 79.14% and 57.74% of the quantum efficiency at room temperature can be maintained at 150, 200 and 300 ℃ respectively, whereby the external quantum efficiency at 200 ℃ can be obtained as 28.0% × 79.14% ≈ 22.2%.

FIG. 10 is an XRD pattern of the phosphor of example 3, and the product prepared by example 3 is Al_1.8Ga_0.2O₃:0.02Cr³⁺。

FIG. 11 is the fluorescence emission spectrum of the phosphor of example 3 excited by the 405nm monochromatic light, and it can be seen from FIG. 11 that the emission peak is near 693nm, the full width at half maximum is about 4.5nm, and in addition, the near infrared broad peak emission near 772nm is observed. Under the excitation condition of 405nm, the internal and external quantum efficiencies of the fluorescent powder are respectively tested to be 99.8 percent and 57.4 percent.

FIG. 12 shows the fluorescence excitation spectrum of the phosphor of example 3 at a wavelength of 693nm, from which FIG. 12 two excitation bands can be seen, the excitation wavelength is 375-600 nm, and the excitation position with the highest intensity is around 405 nm.

FIG. 13 shows fluorescence excitation spectra of the phosphor of example 3 at a wavelength of 772nm, and from FIG. 13, two excitation bands can be seen, and the excitation position with the highest intensity is still around 405 nm.

FIG. 14 is a scattergram showing the change in quantum efficiency with temperature of the phosphor in example 3, wherein 95.68%, 90.91% and 68.59% of the quantum efficiency at room temperature can be maintained at 150, 200 and 300 ℃ respectively, and thus the external quantum efficiency at 200 ℃ can be 57.4% × 90.91% ≈ 52.2%.

FIG. 15 is an XRD pattern of the phosphor of example 4, and the product prepared by example 4 is Al_1.85Ga_0.15O₃:0.01Cr³⁺。

FIG. 16 is the fluorescence emission spectrum of the phosphor of example 4 excited by 405 monochromatic lights, and it can be seen from FIG. 16 that the emission peak is near 693nm and the full width at half maximum is about 3.2 nm. Under the excitation condition of 405nm monochromatic light, the measured internal and external quantum efficiencies are about 100% and 35.7% respectively.

FIG. 17 shows the fluorescence excitation spectrum of the phosphor of example 4 at a wavelength of 693nm, from which FIG. 17 two excitation bands can be seen, the highest position of the intensity corresponding to around 405 nm.

FIG. 18 is a scattergram showing the change in quantum efficiency with temperature of the phosphor in example 4, which is capable of maintaining 95.97%, 93.63% and 83.76% of the quantum efficiency at room temperature at 150, 200 and 300 ℃ respectively under irradiation of a 405nm excitation light source, thereby obtaining an external quantum efficiency of 35.7% x 93.63% or nearly 33.4% at 200 ℃.

FIG. 19 is an XRD pattern of the phosphor of example 5, the product prepared by example 5 being Al_1.75Ga_0.25O₃:0.03Cr³⁺。

FIG. 20 is a fluorescence emission spectrum of the phosphor of example 5 excited by 405 monochromatic light, and it can be seen from FIG. 20 that the emission peak is near 693nm and the full width at half maximum is about 4.8 nm. Under the excitation condition of 405nm monochromatic light, the measured internal and external quantum efficiencies are about 99.2% and 53.5%, respectively.

FIG. 21 is a fluorescence excitation spectrum of the phosphor of example 5 at a wavelength of 693nm, and two excitation bands can be seen from FIG. 21.

FIG. 22 shows fluorescence excitation spectrum of example 5 at 772nm wavelength, and two excitation bands are observed in FIG. 22, with the highest intensity position corresponding to around 405 nm.

Fig. 23 is a scattergram showing the change in quantum efficiency with temperature of the phosphor in example 5, and 96.22%, 87.91% and 59.85% of the quantum efficiency at room temperature can be maintained at 150 ℃, 200 and 300 ℃ using a light source of 405nm as an excitation source, respectively, whereby the external quantum efficiency at 200 ℃ can be 53.5% × 87.91% ≈ 47.0%.

FIG. 24 is an XRD spectrum of the phosphor of comparative example 1, and the product prepared by comparative example 1 is Al_1.95Ga_0.05O₃:0.06Cr³⁺。

FIG. 25 is a fluorescence emission spectrum of the phosphor of comparative example 1 under excitation with 405 monochromatic light, and it can be seen from FIG. 25 that the emission peak is near 693nm and the full width at half maximum is about 3.3 nm. Under the excitation condition of 405nm monochromatic light, the measured internal and external quantum efficiencies are respectively about 32.1% and 19.0%.

FIG. 26 is a fluorescence excitation spectrum of the phosphor of comparative example 1 at a wavelength of 693nm, and from FIG. 26, two excitation bands can be seen, and the highest position of intensity corresponds to around 560 nm.

FIG. 27 is a fluorescence excitation spectrum of the phosphor of comparative example 1 at a wavelength of 772nm, and from FIG. 27, two excitation bands can be seen, and the highest position of intensity corresponds to around 405 nm.

FIG. 28 is a scattergram showing the change in quantum efficiency with temperature of the phosphor in comparative example 1, and by selecting 405nm as an excitation light source, 93.09%, 100.20% and 107.66% of the quantum efficiency at room temperature can be maintained at 150, 200 and 300 ℃ respectively, whereby the external quantum efficiency at 200 ℃ of 19.0% × 100.02% ≈ 19.0% can be obtained.

FIG. 29 is an XRD spectrum of the phosphor of comparative example 2, and the product prepared by comparative example 2 is Al_1.6Ga_0.4O₃:0.001Cr³⁺。

FIG. 30 is a fluorescence emission spectrum of the phosphor of comparative example 2 under excitation with 405 monochromatic light, and it can be seen from FIG. 30 that the emission peak is near 693nm and the full width at half maximum is about 4.8 nm. Under the excitation condition of 405nm monochromatic light, the measured internal and external quantum efficiencies are about 77.3% and 11.8% respectively.

FIG. 31 is a fluorescence excitation spectrum of the phosphor of comparative example 2 at a wavelength of 693nm, and from FIG. 31, two excitation bands can be seen, and the highest position of intensity corresponds to around 560 nm.

FIG. 32 is a scattergram showing the change in quantum efficiency with temperature of the phosphor of comparative example 2, and selecting 405nm as the excitation light source, 89.28%, 73.06% and 43.57% of the quantum efficiency at room temperature can be maintained at 150, 200 and 300 ℃ respectively, whereby the external quantum efficiency at 200 ℃ can be obtained to be 11.8% × 73.06% ≈ 8.6%.

FIG. 33 is an XRD spectrum of the phosphor of comparative example 3, and the product prepared by comparative example 3 is Al_1.9Ga_0.1O₃:0.06Cr³⁺。

FIG. 34 shows the fluorescence emission spectrum of the phosphor of comparative example 3 under excitation of 405 monochromatic lights, and it can be seen from FIG. 34 that the emission peak is near 693nm and the full width at half maximum is about 4.0 nm. Under the excitation condition of 405nm monochromatic light, the measured internal and external quantum efficiencies are about 16.4% and 11.8% respectively.

FIG. 35 is a fluorescence excitation spectrum of the phosphor of comparative example 3 at a wavelength of 693nm, and from FIG. 35, two excitation bands can be seen, the highest position of intensity corresponding to around 405 nm.

FIG. 36 is a fluorescence excitation spectrum of the phosphor of comparative example 3 at a wavelength of 772nm, and from FIG. 36, two excitation bands can be seen, and the highest position of intensity corresponds to around 405 nm.

FIG. 37 is a scattergram showing the change in quantum efficiency with temperature of the phosphor in comparative example 3, and selecting 405nm as the excitation light source, 92.36%, 91.58% and 92.53% of the quantum efficiency at room temperature can be maintained at 150, 200 and 300 ℃ respectively, whereby the external quantum efficiency at 200 ℃ can be obtained to be 11.8% × 91.58% ≈ 10.8%.

FIG. 38 is an XRD spectrum of the phosphor of comparative example 4, and the product prepared by comparative example 4 is Al_1.5Ga_0.5O₃:0.01Cr³⁺。

FIG. 39 is a fluorescence emission spectrum of the phosphor of comparative example 4 under excitation with 405 monochromatic light, and it can be seen from FIG. 39 that the emission peak is near 693nm and the full width at half maximum is about 43.3 nm. Under the condition of 405nm monochromatic light excitation, the measured internal and external quantum efficiencies are respectively about 69.7% and 28.7%.

FIG. 40 is a fluorescence excitation spectrum of the phosphor of comparative example 4 at a wavelength of 693nm, and from FIG. 40, two excitation bands can be seen, and the highest position of intensity corresponds to around 405 nm.

FIG. 41 is a scattergram showing the quantum efficiency of the phosphor of comparative example 4 as a function of temperature, and selecting 405nm as an excitation light source, 73.95%, 52.62% and 18.67% of the quantum efficiency at room temperature can be maintained at 150, 200 and 300 ℃ respectively, whereby the external quantum efficiency at 200 ℃ of 28.7% × 52.62% ≈ 15.1% can be obtained.

FIG. 42 is an XRD spectrum of the phosphor of comparative example 5, and the product prepared by comparative example 5 is Y₃Ga₅O₁₂:0.005Cr³⁺。

FIG. 43 is a fluorescence emission spectrum of the phosphor of comparative example 5 excited by 437 monochromatic light, having an emission peak of 710nm and a full width at half maximum of about 77 nm.

FIG. 44 is a fluorescence excitation spectrum of the phosphor of comparative example 5 at a wavelength of 710nm, and it can be seen from FIG. 40 that the highest position of intensity corresponds to around 437 nm.

Table 1 shows the emission performance data of the phosphors prepared in examples 1 to 5 and comparative examples 1 to 5.

As can be seen from examples 1-5 and comparative examples 1-4, in the phosphors emitting in narrow band, the external quantum efficiency of the phosphor of the present invention is higher than that of the comparative examples, and in comparative example 4, the external quantum efficiency at 25 ℃ is good, but the half-height width is too large, the thermal stability is poor, and the comprehensive performance is still not as good as that of the phosphors in the examples. When the fluorescent powder is applied to health detection equipment as a light source, the fluorescent powder has narrow-band emission characteristics and high luminous efficiency, namely, emission signals are very strong, so that noise signals of a detector can be ignored, namely, the fluorescent powder has higher signal-to-noise ratio, and the problems of low imaging signal-to-noise ratio, low efficiency of lighting or display devices and the like are solved

From examples 1 to 5, it can be seen that the internal quantum efficiency of the phosphor of the present invention at 150, 200, and 300 ℃ can be maintained at 87%, 79%, and 57% or more of the internal quantum efficiency at room temperature, indicating that the phosphor of the present invention has excellent thermal stability and can meet the use requirements of high power devices. Moreover, the full width at half maximum of the emission peak of the fluorescent powder is less than 5nm, narrow-band emission can be realized, and the fluorescent powder has excellent response sensitivity.

It can be seen from the excitation spectra of examples 1 to 5 that, in the excitation spectrum measured when the highest emission peak is detected, the highest position of the excitation band intensity corresponds to 405nm, which indicates that the phosphor of the present invention can be effectively excited by the near ultraviolet light of 405 nm.

As can be seen from examples 1 to 5, Cr³⁺The doping concentration is large, which can cause Cr³⁺Ions are agglomerated and emit near infrared light, and in addition, Cr³⁺Too high a doping concentration causes fluorescence quenching, and thus, the quantum efficiency is lowered.

As can be seen from comparative example 1, the external quantum efficiency of the phosphor is low, so that the sample obtained in comparative example 1 is difficult to meet the actual use requirement.

As can be seen from comparative example 2, the XRD pattern of the phosphor prepared has obviously changed the crystal orientation structure to a great extent due to a large amount of Ga³⁺Incorporation, products not already being of Al₂O₃The matrix, a large number of disordered diffraction peaks appear. The external quantum efficiency of the product is very low, and the actual use requirement is difficult to meet.

As can be seen from comparative example 3, the external quantum efficiency of the phosphor is low, and the actual use requirement is difficult to meet.

As can be seen from comparative example 4, the XRD pattern of the phosphor prepared has obviously changed the crystal orientation structure to a great extent due to a large amount of Ga³⁺Incorporation, products not already being of Al₂O₃The matrix, a large number of disordered diffraction peaks appear. And the full width at half maximum is about 43.3nm, and the response sensitivity of the material with broad peak emission is low, so that the material is difficult to be applied to health detection equipment and high color gamut LED display equipment with high sensitivity requirements. And the luminous efficiency of the LED rapidly decreases along with the temperature rise, and the poor temperature stability is shown, so that the comparative example 4 is difficult to meet the use requirement of an actual high-power device.

As can be seen from comparative example 5, the prepared phosphor can emit 710nm deep red light under 437nm light excitation, but the full width at half maximum of the emission peak is about 77nm, which is difficult to apply to health detection equipment and high color gamut LED display equipment with high requirements on sensitivity.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The narrow-band emission fluorescent powder is characterized in that the molecular formula of the fluorescent powder is Al_2-xGa_xO₃:yCr³⁺Wherein x is more than or equal to 0.1 and less than or equal to 0.3, and y is more than or equal to 0.005 and less than or equal to 0.05.

2. The narrow-band emissive phosphor of claim 1, wherein the phosphor has the formula: al (Al)_2-xGa_xO₃:yCr³⁺Wherein x is more than or equal to 0.15 and less than or equal to 0.25, and y is more than or equal to 0.01 and less than or equal to 0.03.

3. The narrow-band emissive phosphor of claim 2, wherein the phosphor has the formula: al (Al)_1.8Ga_0.2O₃:0.02Cr³⁺Or Al_1.85Ga_0.15O₃:0.01Cr³⁺Or Al_1.75Ga_0.25O₃:0.03Cr³⁺。

4. The preparation method of the narrow-band emission fluorescent powder of claims 1 to 3, characterized by comprising the following steps:

and uniformly mixing an aluminum-containing compound, a gallium-containing compound and a chromium-containing compound, and sintering to obtain the narrow-band emission fluorescent powder, wherein the sintering is to completely react at the temperature of 1400-1600 ℃.

5. The method of claim 4, wherein the sintering temperature is 1500-1580 ℃.

6. Use of the narrow-band emissive phosphor of claims 1-3 in the preparation of LED display devices, plant lighting devices, night vision devices and medical tissue imaging devices.

7. The use according to claim 6, wherein the excitation wavelength of the narrow-band emissive phosphor in said use is 375 to 600 nm.

8. The use according to claim 7, wherein the excitation wavelength of the narrow-band emitting phosphor in said use is 405 nm.

9. The use according to claim 6, wherein the narrow-band emitting phosphor is used at a temperature of-268 to 300 ℃.

10. A health monitoring device, characterized in that the detection light source of the health monitoring device is prepared from the narrow-band emission fluorescent powder of any one of claims 1 to 3.