Self-reduction strontium aluminate long afterglow luminescent material and preparation method thereof in air atmosphere

Abstract

This invention discloses a self-reducing strontium aluminate long-afterglow luminescent material and its preparation method in air atmosphere, belonging to the technical field of long-afterglow luminescent materials. The chemical formula of the self-reducing strontium aluminate long-afterglow luminescent material is Sr. 1‑x‑y‑z‑a Al 2‑b (B b O4:Eu x ,Dy y ,Zr z , of which 0

Description

Technical Field

[0001] This invention relates to the field of long afterglow luminescent materials technology, specifically to a self-reducing strontium aluminate long afterglow luminescent material and its preparation method in an air atmosphere. Background Technology

[0002] Long-afterglow luminescent materials, capable of storing incident light and slowly releasing visible light after the excitation source is removed, are widely used in emergency signage, arts and crafts, and other fields. Against the backdrop of advancing carbon peaking and carbon neutrality projects, the inherent low-carbon properties of this material are particularly important. In recent years, various long-afterglow luminescent materials have emerged, providing options for a wide range of applications.

[0003] Currently, among numerous long-afterglow luminescent materials, the best performing is the europium-dysprosium co-doped strontium aluminate long-afterglow luminescent material, with an afterglow time exceeding 20 hours and a striking yellow-green luminescent color, showing broad application prospects. However, the preparation of this long-afterglow luminescent material requires a reducing atmosphere, which results in high production costs and limits its widespread adoption. References include "The boron effect on low temperature luminescence of SrAl2O4:Eu,Dy" and "Mechanism of long phosphorescence of SrAl2O4:Eu..." 2+ ,Dy 3+ and CaAl2O4,:Eu 2+ ,Nd 3+ The preparation method reported in the article requires a reducing atmosphere. The methods disclosed in Chinese patent applications CN108504353A and CN111635757A also require a reducing atmosphere.

[0004] Since Eu exists in the trivalent form under normal conditions, only divalent Eu can produce a long afterglow effect of yellow-green color in the strontium aluminate matrix. The reducing atmosphere mainly functions to reduce trivalent Eu ions to divalent Eu ions, while generating a large number of O vacancies in the system to achieve the long afterglow effect.

[0005] However, the reducing atmosphere makes the preparation cost of this long-afterglow luminescent material very high. It is estimated that if the reducing atmosphere were eliminated, the production cost could be reduced by about 50%. If a long-afterglow luminescent material of strontium aluminate could be prepared without the aid of a reducing atmosphere, its market prospects would be very broad. Summary of the Invention

[0006] One of the objectives of this invention is to provide a self-reducing strontium aluminate long afterglow luminescent material.

[0007] The second object of the present invention is to provide a preparation method of the above self-reducing strontium aluminate long afterglow luminescent material in an air atmosphere.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] In the first aspect, the present invention provides a self-reducing strontium aluminate long afterglow luminescent material with a chemical general formula of Sr 1-x-y-z- a Al 2-b (B b )O4:Eu x ,Dy y ,Zr z , where 0 < x ≤ 0.01, 0 < y ≤ 0.02, 0 < z ≤ 0.07, 0 < a ≤ 0.05, 0 < b ≤ 0.2.

[0010] In the second aspect, the present invention provides a preparation method of the above self-reducing strontium aluminate long afterglow luminescent material in an air atmosphere, including the following steps:

[0011] S1: Weigh compounds containing Sr, compounds containing Al, compounds containing Eu, compounds containing Dy, compounds containing Zr, and compounds containing B according to the stoichiometric ratios of each element in Sr 1-x-y-z-a Al 2-b (B b )O4:Eu x ,Dy y ,Zr z , 0 < x ≤ 0.01, 0 < y ≤ 0.02, 0 < z ≤ 0.07, 0 < a ≤

[0012] 0.05, 0 < b ≤ 0.2.

[0013] S2: Mix the weighed raw materials and mix and grind them充分混合研磨 to obtain raw material powder.

[0014] S3: Transfer the raw material powder to a crucible, heat it to 1300 - 1500 °C in an air atmosphere, keep it warm for 2 - 6 hours, cool it to room temperature with the furnace, and discharge the material.

[0015] S4: After discharging, perform crushing and grinding to obtain the self-reducing strontium aluminate long afterglow luminescent material.

[0016] Preferably, the compound containing Sr is SrCO3 or SrO, the compound containing Al is Al2O3, the compound containing Eu is Eu2O3, the compound containing Dy is Dy2O3, the compound containing Zr is ZrO2, and the compound containing B is H3BO3 or B2O3.

[0017] Preferably, the heating rate in step S3 is 2-15°C / minute.

[0018] More preferably, the heating rate in step S3 is 5°C / min.

[0019] This invention utilizes the self-reduction property of Eu under special coordination conditions, by introducing high-valence Zr... 4+ Occupy Sr 2 + Lattice sites, forming a large number of negatively charged Sr vacancies within the material system. Experiments have shown that these negatively charged Sr vacancies can be utilized in Eu... 3+ The self-reduction process provides electrons, effectively increasing the degree of self-reduction; on the other hand, the introduction of boron (B) to form a BO tetrahedron within the system increases the efficiency of Eu reduction to some extent. 3+ The self-reduction of ions enabled the preparation of Eu2+-doped strontium aluminate long-afterglow materials in an air atmosphere, freeing the preparation of this material from the need for a reducing atmosphere. Simultaneously, considering the promoting effect of non-stoichiometric ratios on vacancy defect generation, a strontium aluminate long-afterglow luminescent material prepared without the aid of a reducing atmosphere is provided, exhibiting emission spectra and afterglow characteristics comparable to conventional strontium aluminate long-afterglow luminescent materials. The provided self-reducing strontium aluminate long-afterglow luminescent material emits yellow-green fluorescence under excitation by ultraviolet, violet, and blue light, and slowly releases yellow-green optical fibers after the excitation light is removed.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. The preparation of strontium aluminate long afterglow luminescent materials is freed from the reducing atmosphere, significantly reducing production costs. The prepared long afterglow luminescent materials have comparable effects to conventional strontium aluminate long afterglow luminescent materials, making them an ideal substitute for the latter and facilitating market promotion.

[0022] 2. The process of this invention is simple and easy to industrialize. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a SEM image of the self-reducing strontium aluminate long afterglow luminescent material prepared in Example 1 of the present invention;

[0025] Figure 2 The image shows the XRD pattern of the self-reducing strontium aluminate long afterglow luminescent material prepared in Example 1 of this invention.

[0026] Figure 3 The afterglow curves are shown for the self-reducing strontium aluminate long afterglow luminescent materials prepared in Examples 1-5 of this invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] A self-reducing strontium aluminate long afterglow luminescent material with the general chemical formula Sr 0.945 Al 1.9 (B 0.1 O4:Eu 0.005 ,Dy 0.01 ,Zr 0.01 The specific preparation method is as follows:

[0030] S1: Weigh out SrCO3, Al2O3, Eu2O3, Dy2O3, ZrO2 and H3BO3 according to the stoichiometric ratio;

[0031] S2: Mix all the raw materials taken, grind them thoroughly, and obtain raw material powder;

[0032] S3: Transfer the raw material powder to a crucible, heat it to 1350℃ in air atmosphere at a heating rate of 5℃ / min, hold it at that temperature for 6 hours, cool it to room temperature with the furnace, and then discharge the material.

[0033] S4: After discharge, the material is crushed and ground to obtain self-reducing strontium aluminate long afterglow luminescent material.

[0034] like Figure 1-3 As shown, the prepared strontium aluminate long-afterglow luminescent material was tested. XRD showed that its structure was a pure strontium aluminate phase, and SEM showed that its powder particle size was about 100 μm. Afterglow brightness was tested according to GB / T24981.2, and its brightness after 60 minutes without the excitation source was 50.4 mcd / m². 2 It achieves the afterglow performance of typical strontium aluminate long afterglow luminescent materials.

[0035] Example 2

[0036] A self-reducing strontium aluminate long afterglow luminescent material with the general chemical formula Sr 0.885 Al 1.9 (B 0.1O4:Eu 0.005 ,Dy 0.01 ,Zr 0.07 The specific preparation method is as follows:

[0037] S1: Weigh out SrCO3, Al2O3, Eu2O3, Dy2O3, ZrO2 and H3BO3 according to the stoichiometric ratio;

[0038] S2: Mix all the raw materials taken, grind them thoroughly, and obtain raw material powder;

[0039] S3: Transfer the raw material powder to a crucible, heat it to 1450℃ in air atmosphere at a heating rate of 5℃ / min, hold it at that temperature for 3 hours, cool it to room temperature with the furnace, and then discharge the material.

[0040] S4: After discharge, the material is crushed and ground to obtain self-reducing strontium aluminate long afterglow luminescent material.

[0041] like Figure 3 As shown, the afterglow brightness of the prepared strontium aluminate long-afterglow luminescent material was tested according to GB / T24981.2, and its brightness after 60 minutes without the excitation source was 69 mcd / m². 2 It achieves the afterglow performance of typical strontium aluminate long afterglow luminescent materials.

[0042] Example 3

[0043] A self-reducing strontium aluminate long afterglow luminescent material with the general chemical formula Sr 0.898 Al 1.9 (B 0.1 O4:Eu 0.007 ,Dy 0.015 ,Zr 0.05 The specific preparation method is as follows:

[0044] S1: Weigh out SrCO3, Al2O3, Eu2O3, Dy2O3, ZrO2 and H3BO3 according to the stoichiometric ratio;

[0045] S2: Mix all the raw materials taken, grind them thoroughly, and obtain raw material powder;

[0046] S3: Transfer the raw material powder to a crucible, heat it to 1450℃ in air atmosphere at a heating rate of 5℃ / min, hold it at that temperature for 3 hours, cool it to room temperature with the furnace, and then discharge the material.

[0047] S4: After discharge, the material is crushed and ground to obtain self-reducing strontium aluminate long afterglow luminescent material.

[0048] like Figure 3As shown, the afterglow brightness of the prepared strontium aluminate long-afterglow luminescent material was tested according to GB / T24981.2, and its brightness after 60 minutes without the excitation source was 85.5 mcd / m². 2 This demonstrates the superior afterglow performance of strontium aluminate long afterglow luminescent materials.

[0049] Example 4

[0050] A self-reducing strontium aluminate long afterglow luminescent material with the general chemical formula Sr 0.898 Al 1.8 (B 0.2 O4:Eu 0.007 ,Dy 0.015 ,Zr 0.05 The specific preparation method is as follows:

[0051] S1: Weigh out SrCO3, Al2O3, Eu2O3, Dy2O3, ZrO2 and H3BO3 according to the stoichiometric ratio;

[0052] S2: Mix all the raw materials taken, grind them thoroughly, and obtain raw material powder;

[0053] S3: Transfer the raw material powder to a crucible, heat it to 1450℃ in air atmosphere at a heating rate of 5℃ / min, hold it at that temperature for 3 hours, cool it to room temperature with the furnace, and then discharge the material.

[0054] S4: After discharge, the material is crushed and ground to obtain self-reducing strontium aluminate long afterglow luminescent material.

[0055] like Figure 3 As shown, the afterglow brightness of the prepared strontium aluminate long-afterglow luminescent material was tested according to GB / T24981.2, and its brightness after 60 minutes without the excitation source was 78.9 mcd / m². 2 It is superior to Examples 1 and 2, and achieves the afterglow performance of general strontium aluminate long afterglow luminescent materials.

[0056] Example 5

[0057] A self-reducing strontium aluminate long afterglow luminescent material with the general chemical formula Sr 0.9 Al 1.95 (B 0.05 O4:Eu 0.01 ,Dy 0.02 ,Zr 0.05 The specific preparation method is as follows:

[0058] S1: Weigh out SrCO3, Al2O3, Eu2O3, Dy2O3, ZrO2 and H3BO3 according to the stoichiometric ratio;

[0059] S2: Mix all the raw materials taken, grind them thoroughly, and obtain raw material powder;

[0060] S3: Transfer the raw material powder to a crucible, heat it to 1450℃ in air atmosphere at a heating rate of 5℃ / min, hold it at that temperature for 3 hours, cool it to room temperature with the furnace, and then discharge the material.

[0061] S4: After discharge, the material is crushed and ground to obtain self-reducing strontium aluminate long afterglow luminescent material.

[0062] like Figure 3 As shown, the afterglow brightness of the prepared strontium aluminate long-afterglow luminescent material was tested according to GB / T24981.2, and its brightness after 60 minutes without the excitation source was 80.6 mcd / m². 2 It achieves the afterglow performance of typical strontium aluminate long afterglow luminescent materials.

Claims

1. A self-reducing strontium aluminate long afterglow luminescent material, characterized in that, The general chemical formula is Sr 1-x-y-z-a Al 2-b (B b O4:Eu x ,Dy y ,Zr z , where 0 < x ≤ 0.01, 0 < y ≤ 0.02, 0 < z ≤ 0.07, 0 < a ≤ 0.05, 0 < b ≤ 0.2; The preparation method of self-reducing strontium aluminate long afterglow luminescent material in air atmosphere includes the following steps: S1: According to Sr 1-x-y-z-a Al 2-b (B b O4:Eu x ,Dy y ,Zr z The stoichiometric ratios of each element in the following formulas are used to weigh out compounds containing Sr, Al, Eu, Dy, Zr, and B, respectively. S2: Mix the weighed raw materials, grind them thoroughly, and obtain raw material powder; S3: Transfer the raw material powder to a crucible, heat it to 1300-1500℃ in air atmosphere, hold it for 2-6 hours, cool it to room temperature with the furnace, and then discharge the material; S4: After discharge, the material is crushed and ground to obtain a self-reducing strontium aluminate long afterglow luminescent material; the Sr-containing compound is SrCO3 or SrO, the Al-containing compound is Al2O3, the Eu-containing compound is Eu2O3, the Dy-containing compound is Dy2O3, the Zr-containing compound is ZrO2, and the B-containing compound is H3BO3 or B2O3.

2. The self-reducing strontium aluminate long afterglow luminescent material according to claim 1, characterized in that: The heating rate in step S3 is 2-15℃ / minute.

3. The self-reducing strontium aluminate long afterglow luminescent material according to claim 2, characterized in that: The heating rate in step S3 is 5°C / minute.

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