Preparation method and use of yellow fluorescent glass ceramic

Abstract

A preparation method and use of a yellow fluorescent glass ceramic are disclosed. The preparation method includes: mixing a monomer, a cross-linking agent and a filling solvent evenly, then adding fumed silica and stirring evenly, further adding an ultraviolet (UV) photoinitiator and an UV absorber, and stirring thoroughly; adding a yellow phosphor (Y,Gd)AG:Ce, stirring thoroughly and defoaming to obtain a slurry; introducing the slurry into a mold, and curing by UV irradiation or three-dimensional (3D) printing to obtain a body; putting the body into a high-temperature furnace for heating to obtain a phosphor-embedded porous silica glass; putting the porous silica glass into a high-temperature vacuum furnace for densification and sintering to obtain a densified fluorescent glass ceramic; and finally cutting and surface-polishing.

Claims

1. A preparation method of a yellow fluorescent glass ceramic, comprising the following steps: (1) a slurry preparation: mixing a monomer, a cross-linking agent and a filling solvent evenly to obtain a mixed solution; then adding fumed silica to the mixed solution to obtain a first mixture, and stirring the first mixture evenly, wherein a volume ratio of the fumed silica to the mixed solution is 3:7 to 5:5; further adding 0.05-1 wt % of an ultraviolet (UV) photoinitiator and 0.002-0.05 wt % of a UV absorber to the first mixture to obtain a second mixture, and stirring the second mixture thoroughly; finally adding a yellow phosphor (Y,Gd) AG: Ce to the second mixture to obtain a third mixture, stirring thoroughly and defoaming the third mixture to obtain a slurry, wherein a mass ratio of the yellow phosphor to the fumed silica is 1:100 to 15:100, wherein the monomer comprises at least one selected from the group consisting of hydroxyethyl acrylate and 4-hydroxybutyl acrylate, wherein the cross-linking agent comprises polyethylene glycol 400 dibenzoate, and wherein the average particle size of the fumed silica is 10 nm; (2) a curing: introducing the slurry into a mold with a predetermined shape, and curing the slurry by an irradiating with an UV lamp for 20-60 s; (3) a degreasing: putting the body into a high-temperature furnace, heating the body to 600-1,000 C., holding the body in air for 1-10 h to fully decompose and discharge organic matter, and obtaining a phosphor-embedded porous silica glass as a porous precursor; (4) a sintering: putting the porous precursor in a high-temperature vacuum furnace, and performing a densification and the sintering on the porous precursor at 1,050-1,300 C. under vacuum for 0.5-6 h to obtain a densified fluorescent glass ceramic; and (5) a polishing: cutting and surface-polishing the densified fluorescent glass ceramic to obtain the yellow fluorescent glass ceramic with a predetermined size.

2. The preparation method of the yellow fluorescent glass ceramic according to claim 1, wherein in step (1), 55-75 parts by volume of the monomer, 1-8 parts by volume of the cross-linking agent and 15-40 parts by volume of the filling solvent are mixed evenly.

3. The preparation method of the yellow fluorescent glass ceramic according to claim 1, wherein the filling solvent comprises at least one selected from the group consisting of diethylene glycol dibenzoate, phenoxyethanol and ethyl benzoate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an X-ray diffraction (XRD) spectrum of a yellow fluorescent glass ceramic according to Example 2 of the present invention.

(2) FIG. 2 shows excitation and emission spectra of the yellow fluorescent glass ceramic according to Example 2 of the present invention.

(3) FIG. 3 shows a spectrum and parameters of a white light-emitting diode (LED) device packaged with the yellow fluorescent glass ceramic and a blue laser diode (LD) according to Example 2 of the present invention.

(4) FIG. 4 shows a variation of a luminous flux of the white LED device packaged with the yellow fluorescent glass ceramic and the blue LD as a function of an excitation light power according to Example 2 of the present invention.

(5) FIG. 5 shows an electroluminescence spectrum and parameters of a white LED device according to Example 6 of the present invention.

(6) FIG. 6A shows a fluorescent glass ceramic converter prepared in Example 6 of the present invention;

(7) FIG. 6B shows a white LED device packaged with the fluorescent glass ceramic converter prepared in Example 6 of the present invention; and

(8) FIG. 6C shows a hat-shaped body prepared in Example 6 of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(9) The present invention is described in more detail below with reference to the accompanying drawings and specific examples.

(10) The examples of the present invention will be described below.

(11) The yellow phosphor (Y,Gd)AG:Ce, nano-grade fumed silica and other organic raw materials used in the examples are all commercially available.

Example 1

(12) 67 vol % of hydroxyethyl methacrylate, 3 vol % of polyethylene glycol 200 dibenzoate and 30 vol % of diethylene glycol dibenzoate were mixed evenly to obtain a solution. Then fumed silica with an average particle size of 50 nm was added and stirred evenly, where a volume ratio of the fumed silica to the solution was 4:6. Then 0.05 wt % of ultraviolet (UV) photoinitiator 819 and 0.03 wt % of UV absorber Sudan red G were added and stirred thoroughly. Finally, a yellow phosphor (Y,Gd)AG:Ce was added, stirred thoroughly and defoamed to obtain a slurry, where a mass ratio of the yellow phosphor to the fumed silica was 1:100.

(13) The slurry was introduced into a silicone mold and irradiated under a 1,000 W 365 nm UV lamp for 20 s for curing to obtain a body. The body was put into a high-temperature box furnace, and slowly heated to 800 C. by 1 C./min. Then it was held in the air for 3 h to fully decompose and discharge organic matter, thus obtaining a phosphor-embedded porous silica glass as a porous precursor.

(14) The porous precursor was put into a high-temperature vacuum furnace. It was sintered at 1,250 C. under vacuum (about 0.1 Pa) for 2 h to obtain a densified fluorescent glass ceramic. The densified fluorescent glass ceramic was cut and surface-polished to obtain fluorescent glass ceramic sheets of different sizes.

Example 2

(15) 67 vol % of hydroxyethyl methacrylate, 3 vol % of polyethylene glycol 200 dibenzoate and 30 vol % of diethylene glycol dibenzoate were mixed evenly to obtain a solution. Then fumed silica with an average particle size of 50 nm was added and stirred evenly, where a volume ratio of the fumed silica to the solution was 4:6. Then 0.05 wt % of ultraviolet (UV) photoinitiator 819 and 0.03 wt % of UV absorber Sudan red G were added and stirred thoroughly. Finally, a yellow phosphor (Y,Gd)AG:Ce was added, stirred thoroughly and defoamed to obtain a slurry, where a mass ratio of the yellow phosphor to the fumed silica was 5:100.

(16) The slurry was introduced into a silicone mold and irradiated under a 1,000 W 365 nm UV lamp for 20 s for curing to obtain a body. The body was put into a high-temperature box furnace, and slowly heated to 800 C. by 1 C./min. Then it was held in the air for 3 h to fully decompose and discharge organic matter, thus obtaining a phosphor-embedded porous silica glass as a porous precursor.

(17) The porous precursor was put into a high-temperature vacuum furnace. It was sintered at 1,250 C. under vacuum (0.1 Pa) for 2 h to obtain a densified fluorescent glass ceramic. The densified fluorescent glass ceramic was cut and surface-polished to obtain fluorescent glass ceramic sheets of different sizes. An internal quantum efficiency (IQE) of the fluorescent glass ceramic prepared in this example was 73%. The fluorescent glass ceramic sheet was put into a high-pressure hydrothermal kettle for an accelerated aging test, using deionized water as a solvent. After the fluorescent glass ceramic sheet was reacted at 200 C. for 10 h, its luminous intensity did not change, and the glass matrix remained intact.

(18) FIG. 1 is an X-ray diffraction (XRD) spectrum of a sample prepared in this example. It can be seen from FIG. 1 that the fluorescent glass ceramic had both a cubic crystal phase of YAG and an amorphous phase of quartz glass.

(19) FIG. 2 shows excitation and emission spectra of a sample prepared in this example. It can be seen from FIG. 2 that the fluorescent glass ceramic emitted broadband yellow light with a peak wavelength of 550 nm under the excitation of blue light at 420-500 nm.

(20) FIG. 3 shows a spectrum and parameters of a high-power white LED device packaged with the fluorescent glass ceramic sheet prepared in this example and a power-tunable blue LD. Under the excitation of 2.23 W light, the device emitted white light of 355 lm, with a correlated color temperature (CCT, Tc) of 6,523, a color rendering index (CRI, Ra) of 73.6 and coordinates of (0.32,0.31) in a Commission Internationale d'Eclairage (CIE) system.

(21) FIG. 4 shows a variation of a luminous flux of the white LED device with an excitation light power.

Example 3

(22) 67 vol % of hydroxyethyl methacrylate, 3 vol % of polyethylene glycol 200 dibenzoate and 30 vol % of diethylene glycol dibenzoate were mixed evenly to obtain a solution. Then fumed silica with an average particle size of 50 nm was added and stirred evenly, where a volume ratio of the fumed silica to the solution was 4:6. Then 0.05 wt % of ultraviolet (UV) photoinitiator 819 and 0.03 wt % of UV absorber Sudan red G were added and stirred thoroughly. Finally, a yellow phosphor (Y,Gd)AG:Ce was added, stirred thoroughly and defoamed to obtain a slurry, where a mass ratio of the yellow phosphor to the fumed silica was 15:100.

(23) The slurry was introduced into a silicone mold and irradiated under a 1,000 W 365 nm UV lamp for 20 s for curing to obtain a body. The body was put into a high-temperature box furnace, and slowly heated to 800 C. by 1 C./min. Then it was held in the air for 3 h to fully decompose and discharge organic matter, thus obtaining a phosphor-embedded porous silica glass as a porous precursor.

(24) The porous precursor was put into a high-temperature vacuum furnace. It was sintered at 1,250 C. under vacuum (0.1 Pa) for 2 h to obtain a densified fluorescent glass ceramic. The densified fluorescent glass ceramic was cut and surface-polished to obtain fluorescent glass ceramic sheets of different sizes.

Example 4

(25) 67 vol % of hydroxyethyl methacrylate, 3 vol % of polyethylene glycol 200 dibenzoate and 30 vol % of diethylene glycol dibenzoate were mixed evenly to obtain a solution. Then fumed silica with an average particle size of 10 nm was added and stirred evenly, where a volume ratio of the fumed silica to the solution was 4:6. Then 0.05 wt % of ultraviolet (UV) photoinitiator 819 and 0.03 wt % of UV absorber Sudan red G were added and stirred thoroughly. Finally, a yellow phosphor (Y,Gd)AG:Ce was added, stirred thoroughly and defoamed to obtain a slurry, where a mass ratio of the yellow phosphor to the fumed silica was 5:100.

(26) The slurry was introduced into a silicone mold and irradiated under a 1,000 W 365 nm UV lamp for 20 s for curing to obtain a body. The body was put into a high-temperature box furnace, and slowly heated to 800 C. by 1 C./min. Then it was held in the air for 3 h to fully decompose and discharge organic matter, thus obtaining a phosphor-embedded porous silica glass as a porous precursor.

(27) The porous precursor was put into a high-temperature vacuum furnace. It was sintered at 1,150 C. under vacuum (0.1 Pa) for 2 h to obtain a densified fluorescent glass ceramic. The densified fluorescent glass ceramic was cut and surface-polished to obtain fluorescent glass ceramic sheets of different sizes.

Example 5

(28) 67 vol % of hydroxyethyl methacrylate, 3 vol % of polyethylene glycol 200 dibenzoate and 30 vol % of diethylene glycol dibenzoate were mixed evenly to obtain a solution. Then fumed silica with an average particle size of 10 nm was added and stirred evenly, where a volume ratio of the fumed silica to the solution was 4:6. Then 0.05 wt % of ultraviolet (UV) photoinitiator 819 and 0.03 wt % of UV absorber Sudan red G were added and stirred thoroughly. Finally, a yellow phosphor (Y,Gd)AG:Ce was added, stirred thoroughly and defoamed to obtain a slurry, where a mass ratio of the yellow phosphor to the fumed silica was 5:100.

(29) The slurry was introduced into a silicone mold and irradiated under a 1,000 W 365 nm UV lamp for 20 s for curing to obtain a body. The body was put into a high-temperature box furnace, and slowly heated to 800 C. by 1 C./min. Then it was held in the air for 3 h to fully decompose and discharge organic matter, thus obtaining a phosphor-embedded porous silica glass as a porous precursor.

(30) The porous precursor was put into a high-temperature vacuum furnace. It was sintered at 1,150 C. under vacuum (0.1 Pa) for 2 h to obtain a densified fluorescent glass ceramic. The densified fluorescent glass ceramic was cut and surface-polished to obtain fluorescent glass ceramic sheets of different sizes.

Example 6

(31) 67 vol % of hydroxyethyl methacrylate, 3 vol % of polyethylene glycol 200 dibenzoate and 30 vol % of diethylene glycol dibenzoate were mixed evenly to obtain a solution. Then fumed silica with an average particle size of 50 nm was added and stirred evenly, where a volume ratio of the fumed silica to the solution was 4:6. Then 0.05 wt % of ultraviolet (UV) photoinitiator 819 and 0.03 wt % of UV absorber Sudan red G were added and stirred thoroughly. Finally, a yellow phosphor (Y,Gd)AG:Ce was added, stirred thoroughly and defoamed to obtain a slurry, where a mass ratio of the yellow phosphor to the fumed silica was 5:100.

(32) The slurry was introduced into a feeder of a liquid crystal display (LCD) light-curing 3D printer (with a light source having a wavelength of 405 nm), and a pre-designed shape (such as a hat shape shown in FIG. 6C) and a pre-designed size were printed out through software control. The body was put into a high-temperature box furnace, and slowly heated to 600 C. by 1 C./min. Then it was held in the air for 3 h to fully decompose and discharge organic matter, thus obtaining a phosphor-embedded porous silica glass as a porous precursor.

(33) The porous precursor was put into a high-temperature vacuum furnace. It was sintered at 1,250 C. under vacuum (0.1 Pa) for 2 h to obtain a densified fluorescent glass ceramic. The densified fluorescent glass ceramic was polished to obtain a fluorescent glass ceramic converter with a complex shape, where an IQE of the fluorescent glass ceramic convert was 79%.

(34) FIGS. 6A-C shows a hat-shaped body and a fluorescent glass ceramic converter prepared in this example and a white LED device packaged with the fluorescent glass ceramic converter. A bottom size of the hat-shaped fluorescent glass ceramic converter was designed to be the same as a commercially available 1 W blue chip, so it could be directly used for packaging a white LED device. FIG. 5 shows an electroluminescence spectrum and parameters of the white LED device. The device had a luminous efficiency (LE) of 96 lm/W, a CCT (Tc) of 5,096, a CRI (Ra) of 64.5 and coordinates of (0.35,0.41) in a CIE system.

(35) Obviously, the above examples are merely intended to clearly describe the present invention, and other changes or alterations may be made on the basis of the above description. Therefore, obvious changes or alterations made accordingly should still fall within the protection scope of the claims of the invention. In the preparation method for a yellow fluorescent glass ceramic provided by the present invention, the organic solvent used is a light-curing organic solvent. However, a thermal-curing organic solvent may also be used, and the desired body may be obtained by thermal curing.

(36) It can be seen from the implementations of the present invention that the method of the present invention has a simple process and integrates 3D printing to quickly prepare a fluorescent glass ceramics with a complex shape and stable physical and chemical properties. The yellow fluorescent glass ceramic can be packaged with a high-power LED or LD to form a high-brightness white LED device, which can be used in high-power lighting and display.