Carbon-free reduction one-step synthesis method of Gd2O2S: Tb < 3 + > fluorescent material

Abstract

The invention discloses a carbon-free reduction one-step synthesis method of a Gd2O2S: Tb < 3 + > fluorescent material. The method comprises the following steps: weighing raw materials Gd2O3, Gd2 (SO4) 3.8 H2O, Tb4O7, Na2CO3, C6H8O7 and (C6H10O5) n according to a stoichiometric ratio, and grinding until the raw materials are uniformly mixed; according to the method, a CO reducing atmosphere provided by traditional carbon powder calcination is replaced by an adding mode of combining two reducing agents, and a pure-phase fluorescent material is obtained through high-temperature one-step sintering. In the reaction process of preparing the Gd2O2S: Tb < 3 + > fluorescent material, generation of harmful gas is reduced, the problem of environmental pollution is solved, and the preparation method is a simple and environment-friendly preparation technology.

Description

Technical Field

[0001] The present invention relates to Gd 2 O 2 S:Tb 3+ A one-step carbon-free reduction synthesis method for fluorescent materials, which can prepare Gd in one step by selecting and adjusting the added reducing agent and the proportion 2 O 2 S:Tb 3+ Fluorescent materials belong to the field of optoelectronic functional materials. Background Art

[0002] Rare earth luminescent materials have been widely used in different fields, among which rare earth doped oxysulfide-based fluorescent materials are excellent luminescent materials. Rare earth doped oxysulfide-based fluorescent materials have significant application value in up / down conversion luminescence, long afterglow luminescence, X-ray luminescence, cathode ray luminescence and other application fields.

[0003] Rare earth oxysulfides have the advantages of high luminescence efficiency, low phonon energy, strong chemical stability, good thermal stability, excellent light absorption efficiency and energy transfer efficiency, and they play an important role in the phosphor industry. 2 O 2 S) is a good rare earth ion phosphor matrix. 2 O 2 S:Tb 3+ Gd phosphor is considered to be one of the most effective phosphors in X-ray, cathode ray and ultraviolet imaging systems. 2 O 2 S:Tb 3+ The main methods include high temperature solid phase method, solvent thermal method, combustion method and co-precipitation reduction method. 2 S gas reacts with oxide nanocrystals at high temperature to prepare nano-sulfur oxides: first, nano-Y is prepared by combustion method. 2 O 3 :Tb oxide particles were then placed in a shallow crucible and placed in a tube furnace under H 2 S atmosphere at 800℃ for 15min to obtain nano Y 2 O 2 S:Tb particles. In 2015, Sang Xiaotong et al. synthesized Gd by reduction method. 2 O 2 S:Eu 3+ Luminescent powder, using hydrated rare earth nitrate, ammonium sulfate and sodium hydroxide as experimental raw materials, synthesized Gd by reduction method 2 O 2 S:Eu 3+Luminescent powder. The particle size of the powder is about 1 μm, and it is severely agglomerated. Under the excitation of 323 nm, it produces red light emission, and the main emission peak is 628 nm. In 2016, Lian Jingbao et al. synthesized Gd 2 O 2 S:Pr 3+ Phosphor, it was found that the precursor was converted into a single-phase Gd after calcination in air atmosphere. 2 O 2 SO 4 The powder can be converted into a single-phase quasi-spherical Gd 2 O 2 S powder, the particle size is about 1μm, and the phosphor agglomerates seriously. In 2020, Zhang Changlong et al. successfully synthesized Er by high temperature solid phase method. 3+ , Yb 3+ Co-doped Y 2 O 2 S, and carried out research on upconversion luminescence performance and color regulation under multi-frequency excitation. In 2022, Qin et al. successfully prepared tunable multicolor Gd with hexagonal crystal structure and good luminescence performance through solvent thermal synthesis combined with sulfur calcination. 2 O 2 S:Tb 3+ , Sm 3+ Phosphor, the sample is in capsule shape and uniform in size. 2 O 2 S:Tb 3+ High-temperature solid-phase and carbon thermal reduction methods are commonly used for fluorescent materials. Both methods require the addition of carbon powder during the synthesis process. Carbon powder serves as a raw material and a reducing agent to provide a CO reducing atmosphere during the calcination process. However, at high temperatures, carbon powder may react with other components in the system to generate unnecessary impurities or by-products. In addition, the addition of carbon powder may also lead to uneven product particle size and even agglomeration, reducing the filling and dispersibility of the powder. Based on this, the present invention has developed a high-temperature solid-phase synthesis method that does not require carbon powder. Summary of the invention

[0004] The present invention uses Gd 2 O 3 , Gd 2 (SO 4 ) 3 8H 2 O、Tb 4 O 7 、Na 2 CO 3 , C 6 H 8 O 7 and (C 6 H10 O 5 )n as raw material, and through innovative raw material selection and reducing agent addition, the process was optimized, so that Gd can be prepared in one step by carbon-free reduction. 2 O 2 S:Tb 3+ Fluorescent material.

[0005] The present invention is based on the traditional carbon thermal reduction. 2 O 3 and Gd 2 (SO 4 ) 3 8H 2 Add C to the raw material 6 H 8 O 7 and (C 6 H 10 O 5 )n reducing agent, providing reducing agent and CO reducing atmosphere, replacing the traditional carbon powder as reducing agent. Specifically, Gd 2 O 3 , Gd 2 (SO 4 ) 3 8H 2 O、Tb 4 O 7 、Na 2 CO 3 , C 6 H 8 O 7 and (C 6 H 10 O 5 )n is the raw material. Among them, Na 2 CO 3 As sintering aid, C 6 H 8 O 7 and (C 6 H 10 O 5 )n is a reducing agent. Sintering aid Na 2 CO 3 The content is 0-30wt% of the product mass. Reducing agent C 6 H 8 O 7 and (C 6 H 10 O 5 )n content is 0-20wt% and 0-10wt% of the product mass respectively, and the raw material is kept at 1200-1250℃ for 2-3h to obtain the sample. 6 H 8 O7 and (C 6 H 10 O 5 )n reducing agent combination ratio, to achieve a strong reducing atmosphere during the reaction process, promoting the intermediate product Gd 2 O 2 SO 4 SO 4 2+ ions are reduced to S 2+ , speeding up the reaction rate and reducing the temperature required for the reaction, which promotes the growth of grains and makes the lattice development more perfect. 6 H 8 O 7 and (C 6 H 10 O 5 )n reducing agent combination can also play a protective role in the rare earth doping process, solving the problem that some rare earth ions are easily oxidized to high valence states under high temperature reaction conditions, affecting their luminescence effect. The use of carbon-free reduction technology has two advantages. First, adding C 6 H 8 O 7 and (C 6 H 10 O 5 )nReducing agents can inhibit the occurrence of oxidation reactions. Second, they can produce harmless or non-toxic by-products during the reaction and there is no SO 2 The production of polluting gases such as carbon monoxide and carbon dioxide can be reduced, thereby reducing pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 The Gd synthesized by the present invention 2 O 2 S:Tb 3+ XRD patterns of fluorescent material samples.

[0007] Figure 2 The Gd synthesized by the present invention 2 O 2 S:Tb 3+ Photoluminescence emission spectra of fluorescent material samples.

[0008] Figure 3 The Gd synthesized by the present invention 2 O 2 S:Tb 3+ Photoluminescence excitation spectrum of fluorescent material samples.

[0009] Figure 4 The Gd synthesized by the present invention 2 O 2 S:Tb 3+Cathodoluminescence spectrum of a fluorescent material sample. DETAILED DESCRIPTION

[0010] In the present invention, Gd 2 O 2 S:Tb 3+ The specific process of fluorescent materials is described in detail as follows:

[0011] (1) The present invention uses Gd 2 O 3 , Gd 2 (SO 4 ) 3 8H 2 O、Tb 4 O 7 、Na 2 CO 3 , C 6 H 8 O 7 and (C 6 H 10 O 5 )n is the raw material. Among them, Na 2 CO 3 As sintering aid, C 6 H 8 O 7 and (C 6 H 10 O 5 )n is a reducing agent. Sintering aid Na 2 CO 3 The content is 14wt% of the product mass. Reducing agent C 6 H 8 O 7 and (C 6 H 10 O 5 )n contents are 10wt% and 6wt% of the product mass respectively.

[0012] (2) According to the stoichiometric ratio for preparing 5 g of product, a corresponding amount of Gd was weighed using a precision electronic balance. 2 O 3 , Gd 2 (SO 4 ) 3 8H 2 O、Na 2 CO 3 , C 6 H 8 O 7 and (C 6 H 10 O 5 )nRaw materials.

[0013] (3) Pour the weighed raw materials into a mortar and grind them carefully for 20 to 60 minutes to mix the raw materials evenly. Pour the mixed raw materials into a 25 ml crucible.

[0014] (4) Place the 25 ml crucible containing the raw materials into a box-type resistance furnace and heat it from room temperature to 1250°C at a heating rate of 5°C / min and keep it at that temperature for 2 h.

[0015] (5) The furnace is cooled to room temperature, and after acid washing, water washing, and drying to remove impurities, Gd 2 O 2 S:Tb 3+ Fluorescent material samples.

[0016] Figure 1 Gd prepared after pickling, water washing and drying to remove impurities 2 O 2 S:Tb 3+ The XRD spectrum of the fluorescent material sample is consistent with the diffraction peak of the standard card PDF#26-1422, indicating that Gd was successfully synthesized. 2 O 2 S phase.

[0017] Figure 2 The prepared Gd 2 O 2 S:Tb 3+ Photoluminescence emission spectrum of fluorescent material samples. 6 H 8 O 7 When the content is 10wt% of the product mass, the reducing agent (C 6 H 10 O 5 ) When the n content is 6wt% of the product mass, it has the highest emission peak at 544nm under 292nm ultraviolet light excitation.

[0018] Figure 3 The prepared Gd 2 O 2 S:Tb 3+ Photoluminescence excitation spectrum of fluorescent material sample. The excitation spectrum of the sample is a broadband spectrum with a peak at 292nm, and it can emit bright green light under ultraviolet light excitation.

[0019] Figure 4 The prepared Gd 2 O 2 S:Tb 3+ The cathode luminescence spectrum of the fluorescent material sample shows that under the excitation of cathode rays, the sample has the highest green emission peak at 544nm.

Claims

1.Gd2O2S:Tb 3+ A one-step carbon-free reduction synthesis method for fluorescent materials is characterized by: using Gd2O3, Gd2(SO4)3·8H2O, Tb4O7, Na2CO3, C6H8O7 and (C6H 10 O5)n as raw materials, Na2CO3 as sintering aid, C6H8O7 and (C6H 10 O5)n is a reducing agent, the content of Na2CO3 is 0-30wt% of the product mass, the reducing agent C6H8O7 and (C6H 10 The raw materials were mixed in proportion and calcined at 1200-1250℃ for 2-3h to obtain Gd2O2S:Tb 3 + Fluorescent material.

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