CN107418576A - Rear-earth-doped monoclinic system gadolinium siliate salt fluorescent powder and preparation method thereof - Google Patents

Abstract

A kind of rear-earth-doped monoclinic system gadolinium siliate salt fluorescent powder, its chemical expression are as follows：Gd_2‑xSiO₅：xRE；In formula RE be tri- kinds of elements of Eu, Tb, Sm in any one, x be RE substitute Gd mole, 0.01<x<0.1.Preparation method, as follows：Raw material is stoichiometrically weighed, adds 3 ~ 7wt%BaF₂Grinding is uniform, is put into corundum crucible, and capping is put into calcination in heating furnace, and programming rate is 5 ~ 10 DEG C/min, and calcination temperature is 1450 ~ 1500 DEG C, and soaking time is 2 ~ 3.5 hours；Natural cooling is taken out, and fluorescent powder is obtained after grinding.Fluorescent powder luminous intensity prepared by the present invention is big, technical process is simple and easy.

Description

Rare earth-doped monoclinic gadolinium silicate phosphor powder and preparation method thereof

technical field

The invention belongs to the field of luminescent powder preparation, in particular to a rare earth activated gadolinium silicate fluorescent powder and a preparation method.

Background technique

Monoclinic Y ₂ SiO ₅ (YSO) and Lu ₂ SiO ₅ (LSO) crystal materials are traditional optical substrates. Doped Ce has high light output, high irradiation hardness, low refractive index (small internal reflection loss), medium/high Density and effective atomic number and other advantages, can be widely used in oil well detection, imaging nuclear medicine (PET) and high-energy physics nuclear physics and other applications; doped with Yb can be used as an excellent broadband emitting laser; Er, Yb co-doped It can be used for up-conversion luminescence from infrared to visible light, and the quantum tailoring effect is extremely obvious. The preparation of YSO, LSO, and GSO glass bodies by traditional melt cooling technology also shows excellent transparency (Li Jing, research on the preparation technology of transparent glass-ceramics with high crystallinity. Central South University, 2011). Because YSO and LSO exhibit good thermal insulation performance and corrosion resistance under high temperature conditions, their thin film materials can also be used for thermal barrier coatings (Byung-Koog Jang, et al. Surface & Coatings Technology 2016,308: 24–30; Jia Liu, et al. Journal of the European Ceramic Society 2013,33: 3419–3428; Zhilin Tian, Journal of the European Ceramic Society 2015,35:1923–1932; Zhilin Tian, Journal of the European Ceramic Society 2016,36: 2189 ). There are few studies on powder forms YSO and LSO, and they focus on Eu ³⁺ , Tb ³⁺ , Ce ³⁺ , Sm ³⁺ , Tm ³⁺ (XM Han, et al. Solid State Sciences 2004, 6: 349– 355; Y. Liu, et al. Optical Materials 2004,25: 243–250) after doping. Jiaguo Wang et al. found that RE ₂ SiO ₅ (R=Y, La-Lu) exists in X1 type (low temperature phase, P2 _1/C ) and X2 type (high temperature phase, C2/C), and the composition of gel sol method and temperature have a great influence on the crystal phase, and it is difficult to maintain +3 valence for +3~+4 valence-changing rare earth ions (such as Tb), so a weak reducing atmosphere must be used (Jiaguo Wang. Materials Research Bulletin 2001, 36: 1855–1861 ).

Because (Y _1-x Gd _x ) ₂ SiO ₅ (YGSO), (Lu _1-x Gd _x ) ₂ SiO ₅ (LGSO) crystals can also exhibit good optical matrix properties, people began to pay attention to Gd ₂ SiO ₅ (GSO ) Optical matrix material. The crystal scintillator of GSO:Ce prepared by pulling method (Jie Mingyin et al. Acta Synthetic Crystal, 2005, 34: 136-143), the light output is more than twice that of BGO crystal, and the light attenuation is about 1/7 of that of BGO crystal , high radiation hardness, low refractive index, large density and effective atomic number, etc., are widely used in oil well detection, imaging nuclear medicine (PET) and high energy physics nuclear physics and other applications; GSO:Yb is used as a broadband laser (Ning Kaijie, et al., Acta Synthetic Crystals, 2011, 40:817-827) also showed good performance; and also showed good upconversion luminescence effect on GSO: Er, Yb crystal materials (Han Lin. Rare earth doped laser crystal Research on the non-radiative mechanism and its influence on the luminescent properties of ions, Nankai University, 2009). Generally speaking, the research accumulation in GSO is less, mostly from YSO and LSO, and most of them focus on crystal, glass, and ceramic materials. The research on its powder materials is relatively weak, and the doping types of rare earth ions are also concentrated on Eu ions. For example: Gd ₂ SiO was prepared by Bridgman method (Chen Yonghu, Nuclear Technology, 2002, 25:788-792) and sol-gel method (Bing Yan, Colloids and Surfaces A: Physicochem. Eng. Aspects 287 (2006) 158–162) ₅ : Eu ³⁺ high-vacuum VUV excited high-efficiency phosphors for plasma flat panel display (PDP) and mercury-free fluorescent lamps; Sun Haiying et al. used high-temperature solid-phase method to use Gd ₂ O ₃ , SiO ₂ , and Eu ₂ O ₃ as raw materials for BaF ₂ as a flux and successfully prepared this red phosphor (Sun Haiying, Journal of Changchun University of Science and Technology (Natural Science Edition), 2013, 36:87-89); Song Jialan et al. used high-temperature solid-state method H ₃ SiO ₃ , Y ₂ O _3. Prepare Gd _1.95-x Y _x SiO ₅ :Eu red phosphor with Gd ₂ O ₃ and Eu ₂ O ₃ as raw materials (Chinese Journal of Luminescence, 2000, 21:145-149).

Contents of the invention

The object of the present invention is to provide a rare earth-doped monoclinic gadolinium silicate fluorescent powder and a preparation method thereof.

The chemical expression of the rare earth-doped monoclinic gadolinium silicate phosphor powder described in the present invention is as follows:

Gd _2-x SiO ₅ : xRE

In the formula, RE is any one of the three elements of Eu, Tb, and Sm, and x is the molar amount of Gd replaced by RE, 0.01<x<0.1. When RE is Eu, it emits red fluorescence (main peak at 620nm) under excitation at 277nm, 396nm, and 466nm. When RE is Tb, it emits green fluorescence (main peak at 548nm) under excitation at 247nm, 277nm, and 315nm. When RE is Sm, it emits pink fluorescence (main peak at 602nm) under excitation at 292nm and 402nm.

The preparation method of a rare earth-doped monoclinic gadolinium silicate fluorescent powder according to the present invention comprises the following steps: weighing the raw materials according to the stoichiometric ratio, adding 3~7wt% BaF ₂ to grind evenly, and putting in corundum In the crucible, cover it and put it in a heating furnace for burning, the heating rate is 5~10℃/min, the burning temperature is 1450~1500℃, and the holding time is 2~3.5 hours; take it out after natural cooling, and get the phosphor powder after grinding .

The invention adopts the solid-phase sintering method under weak reducing atmosphere to prepare fluorescent powder, the raw materials used are rare earth oxide (99.95%) and silicon monoxide (99.0%, analytically pure), and the weak reducing atmosphere is provided by silicon monoxide.

The fluorescent powder prepared by the invention has high luminous intensity and simple process.

Description of drawings

Fig. 1 is the XRD spectrum of the Gd ₂ SiO ₅ powder prepared in Example 1, the abscissa is 2θ ( ⁰ ), and the ordinate is intensity (au).

Fig. 2 Excitation and emission fluorescence spectra of Gd _2-x SiO ₅ : xEu red phosphor powder prepared in Examples 2 and 3, the abscissa is the wavelength (nm), and the ordinate is the luminous intensity (au).

Fig. 3 Excitation and emission fluorescence spectra of Gd _2-x SiO ₅ : xTb green phosphor powder prepared in Examples 4 and 5, the abscissa is the wavelength (nm), and the ordinate is the luminous intensity (au).

Fig. 4 Excitation and emission fluorescence spectra of Gd _2-x SiO ₅ : xSm pink phosphor powder prepared in Examples 6 and 7, the abscissa is the wavelength (nm), and the ordinate is the luminous intensity (au).

detailed description

The present invention will be further illustrated in conjunction with the following examples.

Example 1.

Take 36.26g of gadolinium oxide and 4.2g of silicon monoxide, add 3wt% BaF ₂ to grind evenly, put them into a corundum crucible, cover them and put them in a heating furnace for burning, the heating rate is 5~10°C/min, and the burning temperature is 1450°C, the holding time is 3 hours; natural cooling is taken out, and Gd ₂ SiO ₅ powder is obtained after grinding. Figure 1 is the XRD pattern of the powder.

Example 2.

Take 35.90g of gadolinium oxide, 4.2g of silicon monoxide, and 0.35g of europium oxide, add 4wt% BaF ₂ and grind evenly, put them in a corundum crucible, cover them and put them in a heating furnace for burning, the heating rate is 5~10°C/min, The burning temperature is 1500°C, and the holding time is 2 hours; it is taken out by natural cooling, and Gd _1.98 SiO ₅ :0.02Eu powder is obtained after grinding. Figure 2 shows that the phosphor emits red fluorescence (the main peak is 620nm) under the excitation of 277nm, 396nm, and 466nm.

Example 3.

Take 34.81g of gadolinium oxide, 4.2g of silicon monoxide, 1.41g of europium oxide, add 5wt% BaF ₂ and grind evenly, put them in a corundum crucible, cover them and put them in a heating furnace for burning, the heating rate is 5~10°C/min, The burning temperature is 1500°C, and the holding time is 2 hours; it is taken out by natural cooling, and Gd _1.92 SiO ₅ :0.08Eu powder is obtained after grinding. Figure 2 shows that the phosphor emits red fluorescence (the main peak is 620nm) under the excitation of 277nm, 396nm, and 466nm.

Example 4.

Take 36.14g gadolinium oxide, 4.2g silicon monoxide, 0.2 terbium oxide, add 6wt% BaF ₂ and grind evenly, put them into a corundum crucible, cover them and put them in a heating furnace for burning, the heating rate is 5~10°C/min, The burning temperature is 1450°C, and the holding time is 3.5 hours; it is taken out by natural cooling, and Gd _1.99 SiO ₅ :0.01Tb powder is obtained after grinding. Figure 3 shows that the fluorescent powder emits green fluorescence (the main peak is 548nm) under the excitation of 247nm, 277nm, and 315nm.

Example 5.

Take 34.99g of gadolinium oxide, 4.2g of silicon monoxide, and 1.41 g of terbium oxide, add 3wt% BaF ₂ to grind evenly, put them into a corundum crucible, cover them and put them in a heating furnace for burning, the heating rate is 5~10°C/min, The burning temperature is 1450°C, and the holding time is 3.5 hours; it is taken out by natural cooling, and Gd _1.93 SiO ₅ :0.07Tb powder is obtained after grinding. Figure 3 shows that the fluorescent powder emits green fluorescence (the main peak is 548nm) under the excitation of 247nm, 277nm, and 315nm.

Example 6.

Take 35.72g of gadolinium oxide, 4.2g of silicon monoxide, 0.52g of samarium oxide, add 5wt% BaF ₂ and grind evenly, put them into a corundum crucible, cover them and put them in a heating furnace for burning, the heating rate is 5~10°C/min, The burning temperature is 1450°C, and the holding time is 3 hours; it is taken out by natural cooling, and Gd _1.97 SiO ₅ :0.03Sm powder is obtained after grinding. Figure 4 shows that the phosphor emits pink fluorescence (the main peak is 602nm) under excitation at 292nm and 402nm.

Example 7.

Take 35.17g of gadolinium oxide, 4.2g of silicon monoxide, and 1.05g of samarium oxide, add 5wt% BaF ₂ and grind evenly, put them into a corundum crucible, cover them and put them in a heating furnace for burning, the heating rate is 5~10°C/min, The burning temperature is 1450°C, and the holding time is 3 hours; it is taken out by natural cooling, and Gd _1.94 SiO ₅ :0.06Sm powder is obtained after grinding. Figure 4 shows that the phosphor emits pink fluorescence (the main peak is 602nm) under excitation at 292nm and 402nm.

The stoichiometry/processing parameters/luminescence performance comparison of each embodiment of the table

Claims (3)

1. A kind of 1. rear-earth-doped monoclinic system gadolinium siliate salt fluorescent powder, it is characterized in that chemical expression is as follows：

   Gd_2-xSiO₅：xRE

   In formula RE be tri- kinds of elements of Eu, Tb, Sm in any one, x be RE substitute Gd mole, 0.01<x<0.1.
2. 2. a kind of preparation method of rear-earth-doped monoclinic system gadolinium siliate salt fluorescent powder described in claim 1, it is characterized in that As follows：Raw material is stoichiometrically weighed, adds 3 ~ 7wt% BaF₂Grinding is uniform, is put into corundum crucible, capping is put Enter calcination in heating furnace, programming rate is 5 ~ 10 DEG C/min, and calcination temperature is 1450 ~ 1500 DEG C, and soaking time is 2 ~ 3.5 small When；Natural cooling is taken out, and fluorescent powder is obtained after grinding.
3. 3. a kind of preparation method of rear-earth-doped monoclinic system gadolinium siliate salt fluorescent powder according to claim 2, it is special Sign is that raw material is rare earth oxide and silicon monoxide.