CN112125659A

CN112125659A - Fluorescent ceramic for warm white lighting and preparation method thereof

Info

Publication number: CN112125659A
Application number: CN202011102606.8A
Authority: CN
Inventors: 林辉; 段与同; 李宇焜; 胡健; 蒋顺攀; 李席安; 张朴
Original assignee: Zunyi Huitong Academician Technology Co ltd; Guizhou Saiyi Photoelectric Technology Co ltd
Current assignee: Zunyi Huitong Academician Technology Co ltd; Guizhou Saiyi Photoelectric Technology Co ltd
Priority date: 2020-10-15
Filing date: 2020-10-15
Publication date: 2020-12-25

Abstract

The invention provides a fluorescent ceramic for warm white lighting and a preparation method thereof, wherein the chemical formula of the fluorescent ceramic is Tb_3(1‑x)Ce_3xAl_5(1‑2y)Mn_5ySi_5yO₁₂Wherein: x is more than or equal to 0.00005 and less than or equal to 0.15, y is more than or equal to 0.00005 and less than or equal to 0.3, and the preparation method of the fluorescent ceramic comprises the following steps: terbium oxide, aluminum oxide, cerium oxide, silicon dioxide, manganese dioxide and other raw materials are mixed according to a chemical formula Tb_3(1‑x)Ce_3xAl_5(1‑2y)Mn_5ySi_5yO₁₂Proportioning, and preparing according to stoichiometric ratioMixing the fine powder, pressing and molding, carrying out phase change reaction on the pressed blank through heat treatment to generate fluorescent ceramic with terbium aluminum garnet phase, and carrying out Ce reaction at high temperature³⁺Ions and Mn²⁺The ions enter the terbium aluminum garnet structure by diffusion and respectively replace the existing Tb³⁺Ions and Al³⁺The ions become a luminescent center to obtain Ce for warm white light illumination³⁺、Mn²⁺An ion co-activated terbium aluminum garnet phase fluorescent ceramic. The invention has broadband yellow green-orange red fluorescence emission under the excitation of blue light, and the fluorescence peak wavelength can be doped with Ce³⁺，Mn²⁺Is suitable for warm white lighting.

Description

Fluorescent ceramic for warm white lighting and preparation method thereof

Technical Field

The invention belongs to the field of chemical industry, relates to a fluorescent material and a preparation method thereof, and particularly relates to terbium aluminum garnet phase fluorescent ceramic for warm white light illumination and a preparation method thereof.

Background

At present, white light LEDs have become the main light source in the fields of illumination and display gradually because of the advantages of high efficiency, energy conservation, environmental protection, long service life and the like. There are basically two kinds of white light LED synthesis methods, one is a red, green and blue combined white light LED, but this method uses a large number of LEDs for combining the white light LED, the cost is high, and the design is relatively complex due to different conditions such as driving voltage, service life and the like of the LEDs with different colors. Therefore, the widely applied white light LED synthesis scheme is of a fluorescence conversion type, and Ce is excited by a blue light chip³⁺YAG yellow fluorescent powder.

However, commonly used commercial Ce³⁺The YAG fluorescent powder has insufficient red light component in the spectrum, and the white light source prepared by combining the YAG fluorescent powder with a blue light chip mainly has two problems. Firstly, it has high color temperature and cold color, is easy to be nervous and not suitable for indoor relaxingThe environment is bright; secondly, the color rendering index is low, the color reduction degree is insufficient, and the color developing method can not be applied to occasions needing accurate color contrast, such as the fields of medical treatment, military affairs and the like. Thus for Ce³⁺YAG phosphor powder has improved spectrum and increased red light component in the spectrum.

Terbium aluminum garnet fluorescent ceramic (Tb)_3(1-x)Ce_3xAl_5(1-2y)Mn_5ySi_5yO₁₂For example) under the excitation of 420-480 blue light wave band, the light can emit yellow green-orange red light with wide band, and the peak wavelength of the fluorescence can be along with the doping of Ce³⁺，Mn²⁺Is adjusted. In addition, the ceramic material has good physical and chemical stability and good thermal conductivity, can ensure that the fluorescent ceramic material can stably work for a long time, and is a fluorescent material with excellent performance. Has great potential in the application of warm white light illuminating light sources.

At present, the fluorescent ceramic is prepared by a vacuum sintering mode, the vacuum sintering has higher requirements on equipment and environment, and the large-scale industrial production is not facilitated. For the adjustment of the spectrum, a common mode in the market is to add fluoride and nitride red powder, the fluoride nitride is more complex than the oxide fluorescent powder in preparation conditions, and the added red powder can reduce the light extraction efficiency of spectral self-absorption, thereby influencing the luminous intensity

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention provides a preparation method of terbium aluminum garnet phase fluorescent ceramic for warm white lighting, and the preparation method of the terbium aluminum garnet phase fluorescent ceramic has Ce³⁺，Mn²⁺Uniform ion distribution, adjustable spectrum, excellent thermal property, and suitability for warm white light illumination source.

The chemical formula of the fluorescent material is Tb_3(1-x)Ce_3xAl_5(1-2y)Mn_5ySi_5yO₁₂Wherein: x is more than or equal to 0.00005 and less than or equal to 0.15, and y is more than or equal to 0.00005 and less than or equal to 0.3; the method is characterized in that: mixing terbium oxide (Tb)₄O₇) Aluminum oxide (Al)₂O₃) Cerium oxide (CeO)₂) Oxidation of carbon dioxideSilicon (SiO)₂) And manganese dioxide (MnO)₂) According to the formula Tb_3(1-x)Ce_3xAl_5(1-2y)Mn_5ySi_5yO₁₂Proportioning, mixing the powders prepared according to the stoichiometric ratio, pressing and molding, carrying out a phase change reaction on the pressed blank under the atmosphere condition through heat treatment to generate fluorescent ceramics with garnet phases, and carrying out Ce reaction under the high-temperature condition³⁺Ions and Mn²⁺Ion diffusion into garnet structure to replace existing Tb³⁺Ions and Al³⁺The ions become luminescent centers, and the terbium aluminum garnet phase fluorescent ceramic for warm white light illumination is obtained.

Further, the preparation method of the terbium aluminum garnet phase fluorescent ceramic for warm white light illumination comprises the following steps:

(1) according to Tb_3(1-x)Ce_3xAl_5(1-2y)Mn_5ySi_5yO₁₂In the chemical formula Ce³⁺，Mn²⁺Calculating and weighing the mass of various required raw materials according to the target doping concentration of the ions;

(2) weighing terbium oxide, aluminum oxide, cerium oxide, silicon dioxide and manganese dioxide raw materials, and adding the weighed terbium oxide, aluminum oxide, cerium oxide, silicon dioxide and manganese dioxide raw materials into a ball milling tank. Ball-milling by a ball mill to uniformly mix the powder, and drying and sieving the mixed slurry to obtain powder;

(3) biscuiting the sieved powder at 500-1200 ℃, wherein the biscuiting time is 1-24 hours; removing organic matters possibly existing in the powder;

(4) adding the bisque-fired powder into a grinding tool for compression molding, and carrying out heat treatment on the blank in a flowing atmosphere, wherein the heat treatment temperature is 1300-1800 ℃, the heat treatment time is 1-72 hours, and a phase change reaction is generated in the heat treatment process to generate a garnet phase;

(5) cooling to obtain the terbium aluminum garnet fluorescent ceramic for warm white light illumination.

(preferably, the bisque firing temperature in the step 3) is 700-1100 ℃.

(preferably, the bisque firing time in the step 3) is 2 to 10 hours.

(preferably, the temperature of the heat treatment in the step 4) is 1600-1750 ℃.

(preferably, the heat treatment time in the step 4) is 3 to 8 hours.

The invention adopts terbium oxide, aluminum oxide, cerium oxide, silicon dioxide, manganese dioxide and other raw materials as initial raw materials according to a chemical formula, and ball-milling a mixture of powder and absolute alcohol in a ball mill, wherein the ball-milled mixture contains Ce³⁺，Mn²⁺Drying the ionic slurry, then carrying out heat treatment in the atmosphere, and generating a cubic garnet phase through phase change; at the same time, Ce³⁺Ions and Mn²⁺Ion diffusion into garnet structure to replace existing Tb³⁺Ions and Al³⁺The ions become luminescent centers, and the terbium aluminum garnet phase fluorescent ceramic for warm white light illumination is obtained.

Under the excitation of blue light band, there can be wide band yellow green-orange red light emission, and the fluorescence peak wavelength can be doped with Ce³⁺，Mn²⁺Is adjusted. The method has Ce³⁺，Mn²⁺Uniform ion distribution, simple preparation process, adjustable spectrum, excellent thermal property, suitability for warm white light illumination light sources and the like.

The terbium aluminum garnet fluorescent ceramic prepared by the invention is targeted to lock the excellent luminescent matrix phase cubic garnet, and the Ce is ball-milled in alcohol³⁺，Mn²⁺Ion is introduced into garnet structure, and solid phase reaction is performed by atmosphere heat treatment to generate wide-spectrum, compact, high-thermal conductivity Tb_3(1-x)Ce_3xAl_5(1-2y)Mn_5ySi_5yO₁₂Fluorescent ceramic material.

Compared with the prior art, the invention has remarkable technical progress. The invention provides a method for preparing terbium aluminum garnet fluorescent ceramic for warm white light illumination, which comprises Ce³⁺，Mn²⁺The ion distribution is uniform, the controllability is high, the consistency is good, and the like. The terbium aluminum garnet fluorescent ceramic has important application in the fields of high-color-rendering, high-brightness and warm white light illumination LEDs.

Drawings

FIG. 1 shows the ultraviolet rayPhotometer for Tb prepared in example 1_2.9997Ce_0.0003Al_4.99Mn_0.005Si_0.00 ₅O₁₂The fluorescent ceramic tests the resulting transmittance.

FIG. 2 shows Tb obtained in example 1 by X-ray diffractometry_2.9997Ce_0.0003Al_4.99Mn_0.005Si_0.005O₁₂And (3) carrying out an XRD (X-ray diffraction) spectrum of the detection on the fluorescent ceramic.

FIG. 3 shows Tb prepared in example 1 with a thermal conductivity tester_2.9997Ce_0.0003Al_4.99Mn_0.005Si_0.00 ₅O₁₂The heat conductivity coefficient atlas for detecting the fluorescent ceramic.

FIG. 4 shows Tb prepared in example 1 using a fluorescence spectrometer_2.9997Ce_0.0003Al_4.99Mn_0.005Si_0.005O₁₂Fluorescence spectrum of the fluorescent ceramic under 460nm blue light excitation.

FIG. 5 shows Tb prepared in example 1 using an integrating sphere_2.9997Ce_0.0003Al_4.99Mn_0.005Si_0.005O₁₂And the electroluminescent spectrum of the white light LED is obtained after the fluorescent ceramic is packaged with a 460nm blue light chip.

FIG. 6 shows Tb obtained in example 2 by X-ray diffractometry_2.9997Ce_0.0003Al_4.97Mn_0.015Si_0.015O₁₂And (3) carrying out an XRD (X-ray diffraction) spectrum of the detection on the fluorescent ceramic.

FIG. 7 shows Tb prepared in example 2 using a fluorescence spectrometer_2.9997Ce_0.0003Al_4.97Mn_0.015Si_0.015O₁₂Fluorescence spectrum of the fluorescent ceramic under 460nm blue light excitation.

FIG. 8 shows Tb prepared in example 2 using an integrating sphere_2.9997Ce_0.0003Al_4.97Mn_0.015Si_0.015O₁₂And the electroluminescent spectrum of the white light LED is obtained after the fluorescent ceramic is packaged with a 460nm blue light chip.

FIG. 9 is a graph of a sample obtained by X-ray diffractometryTb prepared in example 3_2.9997Ce_0.0003Al_4.95Mn_0.025Si_0.025O₁₂And (3) carrying out an XRD (X-ray diffraction) spectrum of the detection on the fluorescent ceramic.

FIG. 10 shows Tb prepared in example 3 using a fluorescence spectrometer_2.9997Ce_0.0003Al_4.95Mn_0.025Si_0.025O₁₂Fluorescence spectrum of the fluorescent ceramic under 460nm blue light excitation.

FIG. 11 shows Tb prepared in example 3 using an integrating sphere_2.9997Ce_0.0003Al_4.95Mn_0.025Si_0.025O₁₂And packaging the fluorescent ceramic and a 460nm blue light chip to obtain the electroluminescent spectrum of the white light LED.

FIG. 12 shows Tb prepared in example 4 using an ultraviolet spectrophotometer_2.9997Ce_0.0003Al_4.9Mn_0.05Si_0.0 ₅O₁₂The fluorescent ceramic tests the resulting transmittance.

FIG. 13 shows Tb obtained by X-ray diffractometry on sample 4_2.9997Ce_0.0003Al_4.9Mn_0.05Si_0.05O₁₂And (3) carrying out an XRD (X-ray diffraction) spectrum of the detection on the fluorescent ceramic.

FIG. 14 shows Tb prepared in example 4 using a fluorescence spectrometer_2.9997Ce_0.0003Al_4.9Mn_0.05Si_0.05O₁₂Fluorescence spectrum of the fluorescent ceramic under 460nm blue light excitation.

FIG. 15 shows Tb prepared in example 4 using an integrating sphere_2.9997Ce_0.0003Al_4.9Mn_0.05Si_0.05O₁₂And packaging the fluorescent ceramic and a 460nm blue light chip to obtain the electroluminescent spectrum of the white light LED.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

Example 1

With terbium oxide (chemical formula: Tb)₄O₇) Alumina (chemical formula: al (Al)₂O₃) Silica (chemical formula: SiO 2₂) Cerium oxide (chemical formula: CeO (CeO)₂) And manganese dioxide (chemical formula: MnO₂) 209272g of terbium oxide, 9.5038g of aluminum oxide, 0.0112g of silicon dioxide, 0.0019g of cerium oxide and 0.0162g of manganese dioxide are weighed as raw materials. The raw materials are mixed in 18ml of absolute alcohol by ball milling, wherein 90g of agate balls are added in a ball milling pot for assisting in mixing evenly. The mixed slurry was ball milled at 250r/min for 12 hours at room temperature.

After the ball milling is stopped, the slurry is placed in a drying oven at 80 ℃ for drying for 12 hours to obtain dried powder, and the dried powder is sieved by using a 200-mesh nylon mesh screen to obtain fine powder. The fine powder was biscuited in a crucible at 850 ℃ for 5 hours in a muffle furnace.

Putting the bisque-fired powder into a metal film with the inner diameter of 20mm, applying unidirectional pressure of 10MPa for press forming, then densifying the blank by cold isostatic pressing at 200MPa, carrying out heat treatment on the densified blank at 1700 ℃ for 5 hours under the condition of oxygen atmosphere, and cooling to obtain the terbium aluminum garnet phase fluorescent ceramic Tb for warm white lighting_2.9997Ce_0.0003Al_4.99Mn_0.005Si_0.005O₁₂。

The ultraviolet-visible spectrophotometer is used for testing the transmission spectrum of the fluorescent ceramic prepared in the embodiment, and as shown in fig. 1, the fluorescent ceramic has a certain transmittance in the range of 400-800 nm.

The phase composition of the fluorescent ceramic prepared in this example was detected by an X-ray diffractometer, and the data of the detection results showed that the phase of the fluorescent ceramic was cubic garnet, and the XRD spectrum was as shown in fig. 2.

The thermal conductivity of the fluorescent material prepared in this example was measured at 25 ℃, 100 ℃, 200 ℃ and 300 ℃ using a thermal conductivity tester, and the thermal conductivity spectrum is shown in fig. 3.

The fluorescence spectrum of the fluorescent material prepared in this example under the excitation of 460nm blue light was measured by a fluorescence spectrometer, and the measurement results are shown in fig. 4.

As can be seen from FIG. 4, the terbium aluminum garnet ceramic prepared in this example can generate broadband light emission under the excitation of blue light, the luminescent peak position is 572nm, and the half width height of the luminescent peak is 132 nm.

The electroluminescent spectrum of the white light LED device obtained by encapsulating the fluorescent ceramic prepared in this example with a 460nm blue light chip was tested by using integrating sphere equipment, and the test result is shown in fig. 5.

Example 2

EXAMPLE 2 preparation of a fluorescent ceramic Material essentially the same as in example 1, except that the starting materials used were terbium oxide, alumina, silica, ceria and manganese dioxide, except that Mn²⁺，Si⁴⁺Relative to Al³⁺The doping amount of (2) was 0.015.

And detecting the phase composition of the obtained fluorescent ceramic by using an X-ray diffractometer, wherein the phase of the fluorescent ceramic obtained on the surface of the detection result data is still a cubic garnet phase, and an XRD (X-ray diffraction) spectrum is shown in figure 6.

The fluorescence spectrum of the fluorescent material prepared in this example under the excitation of 460nm blue light was measured by a fluorescence spectrometer, and the measurement results are shown in fig. 7. A broadband light emission with a peak value of 585nm and a full width at half maximum of 134nm was obtained.

The electroluminescent spectrum of the white light LED device obtained by encapsulating the fluorescent ceramic prepared in this example with a 460nm blue light chip was tested by using integrating sphere equipment, and the test result is shown in fig. 8.

Example 3

EXAMPLE 3 preparation of a fluorescent ceramic Material essentially the same as in example 1, except that the starting materials used were terbium oxide, alumina, silica, ceria and manganese dioxide, except that Mn²⁺，Si⁴⁺Relative to Al³⁺The doping amount of (3) is 0.025.

And detecting the phase composition of the obtained fluorescent ceramic by using an X-ray diffractometer, wherein the phase of the fluorescent ceramic obtained on the surface of the detection result data is still a cubic garnet phase, and an XRD (X-ray diffraction) spectrum is shown in figure 9.

The fluorescence spectrum of the fluorescent material prepared in this example under the excitation of 460nm blue light was measured by a fluorescence spectrometer, and the measurement result is shown in fig. 10. A broadband light emission with a peak of 590nm and a full width at half maximum of 132nm was obtained.

The electroluminescent spectrum of the white light LED device obtained by encapsulating the fluorescent ceramic prepared in this example with a 460nm blue light chip was tested by using integrating sphere equipment, and the test result is shown in fig. 11.

Example 4

EXAMPLE 4 preparation of a fluorescent ceramic Material essentially the same as in example 1, except that the starting materials used were terbium oxide, alumina, silica, ceria and manganese dioxide, except that Mn²⁺，Si⁴⁺Relative to Al³⁺The doping amount of (3) is 0.05.

The ultraviolet-visible spectrophotometer is adopted to test the transmission spectrum of the fluorescent ceramic prepared in the embodiment, and as shown in fig. 12, the fluorescent ceramic has certain transmittance in the range of 400-800 nm

And detecting the phase composition of the obtained fluorescent ceramic by using an X-ray diffractometer, wherein the phase of the fluorescent ceramic obtained on the surface of the detection result data is still a cubic garnet phase, and an XRD (X-ray diffraction) spectrum is shown in figure 13.

The fluorescence spectrum of the fluorescent material prepared in this example under the excitation of 460nm blue light was measured by a fluorescence spectrometer, and the measurement result is shown in fig. 14. A broadband light emission with a peak of 605nm and a full width at half maximum of 124nm was obtained.

The electroluminescent spectrum of the white light LED device obtained by encapsulating the fluorescent ceramic prepared in this example with a 460nm blue light chip was tested by using integrating sphere equipment, and the test result is shown in fig. 15.

As can be seen from the above examples, the invention provides a method for preparing terbium aluminum garnet phase fluorescent ceramic for warm white lighting, and Ce is subjected to ball milling³⁺，Mn²⁺The luminous ions are uniformly distributed, the preparation requirement of the sample is reduced by the process of sintering the ceramic at normal pressure, and the Ce is adjusted³⁺，Mn²⁺Doping concentration of luminescent ionsA luminescence spectrum suitable for warm white lighting applications can be prepared.

In conclusion, the method has the advantages of simple preparation process, adjustable spectrum, excellent thermal performance, suitability for warm white light illumination light sources and the like.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fluorescent ceramic for warm white lighting and its preparation method, the chemical formula of the fluorescent material is Tb_3(1-x)Ce_3xAl_5(1-2y)Mn_5ySi_5yO₁₂Wherein: x is more than or equal to 0.00005 and less than or equal to 0.15, and y is more than or equal to 0.00005 and less than or equal to 0.3; the method is characterized in that: mixing terbium (Tb) heptaoxide₄O₇) Or terbium (Tb) oxide₂O₃) Aluminum oxide (Al)₂O₃) Cerium oxide (CeO)₂) Silicon dioxide (SiO)₂) And manganese dioxide (MnO)₂) According to the formula Tb_3(1-x)Ce_3xAl_5(1-2y)Mn_5ySi_5yO₁₂Proportioning, mixing the powders prepared according to the stoichiometric ratio, pressing and molding, carrying out a phase change reaction on the pressed blank through heat treatment to generate terbium aluminum garnet phase fluorescent ceramic, and carrying out Ce reaction at high temperature³⁺Ions and Mn²⁺Ion diffusion into pomegranateStone structures replacing respectively the existing Tb³⁺Ions and Al³⁺The ions become luminescent centers, and the terbium aluminum garnet phase fluorescent ceramic for warm white light illumination is obtained.

2. The method of preparing terbium aluminum garnet phase fluorescent ceramic for warm white light illumination according to claim 1, characterized by comprising the steps of:

(4) adding the bisque-fired powder into a grinding tool for compression molding, sintering the blank in a vacuum furnace, a hot pressing furnace or a flowing atmosphere high-temperature furnace, wherein the sintering heat preservation temperature is 1300-1800 ℃, the heat preservation time is 1-72 hours, and a phase change reaction is generated in the sintering process to generate a garnet phase;