Bi-doped europium salt phosphor and preparation method thereof

Abstract

The present invention discloses a Bi-doped europium salt phosphor and a preparation method and application thereof, belonging to the technical field of luminescent materials. The Bi-doped europium salt phosphor of the present invention has a chemical formula of Ba y S E 4 O 8 :xBi; where y is the amount of Ba, 0.95≤y≤1, and x is the doping amount of Bi, 0≤x≤0.05. y S E 4 O 8 The color change is faster and more obvious, which helps to achieve more efficient color change and color display. In addition, by selecting different doping ions and doping concentrations and changing the excitation power, the color change degree can be adjusted, which can be used for erasable optical information recording and intelligent optical switching.

Description

Technical Field

[0001] The invention belongs to the technical field of luminescent materials, and in particular relates to a Bi-doped europium salt phosphor and a preparation method thereof. Background Art

[0002] Lanthanide-doped inorganic photoluminescent materials whose fluorescence intensity can be modulated under external stimuli such as light, electric field, magnetic field, and temperature have great application potential in detection, sensing, anti-counterfeiting, and biological probes. Among these external stimuli, light stimulation has the advantages of being easy to obtain and easy to control, and is an ideal means of stimulation. Photochromic materials can respond to light stimulation in at least one color change direction and have been used in the fields of optical storage and optical switching. Lanthanide-doped inorganic photochromic materials have both good luminescence and photochromic properties, and their fluorescence intensity can be modulated based on the photochromic reaction. This material has a very broad application prospect in the field of optoelectronics.

[0003] Existing photochromic materials are mainly divided into inorganic photochromic materials and organic photochromic materials. However, organic photochromic materials are limited in their application due to their slow reaction speed, easy aging, short duration, poor thermal stability, etc. Compared with organic photochromic materials, inorganic photochromic materials have the advantages of fast reaction speed, strong anti-aging ability, long color change time, good thermal stability, etc., but existing inorganic photochromic materials still have the disadvantage of slow reaction speed. Summary of the invention

[0004] The main purpose of the present invention is to provide a Bi-doped europium salt phosphor and a preparation method thereof, wherein Bi is doped into the europium salt material to obtain Ba y SrEu4O8:xBi material produces color changes under 365nm light excitation.

[0005] To achieve the above object, the present invention provides a Bi-doped europium salt phosphor, the chemical formula of which is Ba y SrEu4O8:xBi; wherein y is the amount of Ba, 0.95≤y≤1, and x is the doping amount of Bi, 0≤x≤0.05.

[0006] As a further improvement of the present invention, y is the amount of Ba, 0.95≤y≤0.999, x is the doping amount of Bi, 0.001<x≤0.05.

[0007] A preparation method of Bi-doped europium salt phosphor comprises the following steps: uniformly mixing Eu2O3, BaCO3, SrCO3 and Bi2O3 into mixed powder, grinding and calcining, and cooling to obtain Bi-doped europium salt phosphor.

[0008] As a further improvement of the present invention, ethanol is added during the grinding, the volume ratio of ethanol to mixed powder mass is: 3-8 ml:3 g, and the grinding time is 10-60 min.

[0009] As a further improvement of the present invention, the calcination temperature is 1500-1600° C., the time is 4-20 hours, and the calcination atmosphere is air.

[0010] As a further improvement of the present invention, the cooling rate is 1-3°C / min.

[0011] The present invention also claims to protect the application of the Bi-doped europium salt phosphor in erasable optical information recording or intelligent optical switching.

[0012] The present invention is based on Ba y SrEu4O8 is the matrix carrier, Bi is the color change center, and the prepared Ba y The photochromic and photoluminescent properties of SrEu4O8:xBi phosphors can meet the requirements of optical storage media. Due to the presence of electron traps in the microstructure of the material, when the material is stimulated by light in a specific band, the matrix carrier absorbs energy, most of which will be converted into photons by the Eu luminescence center and released, and a very small part will be captured by the oxygen vacancy defects in the matrix carrier, causing discoloration. Therefore, Ba y The electron capture and desorption in the oxygen vacancies of SrEu4O8:xBi lead to the formation of Ba y SrEu4O8:xBi ceramics exhibit reversible photochromism from white or light yellow to gray-brown under alternating irradiation of 365nm ultraviolet light and natural light. For europium salt materials, Bi doping broadens the Ba y The absorption band of SrEu4O8 is enhanced, and the excited electrons are provided. When doped with Bi, the oxygen vacancy defects in the matrix carrier increase, resulting in an enhanced color change effect. In addition, the degree of color change and bleaching is related to the illumination time.

[0013] In addition, oxygen defects form electron traps, capture excited electrons and become F-type color centers (defect sites in the crystal that selectively absorb visible light due to alkali metal diffusion). Photochromism in oxide semiconductors involves the migration of photogenerated electrons and holes in the semiconductor and the generation of color centers. Finally, the color center absorbs visible light and causes color change.

[0014] The beneficial effects of the present invention are as follows: the present invention dopes Bi into Ba y SrEu4O8 achieves faster and more obvious color change, which helps to achieve more efficient color change and color display. In addition, by selecting different doping ions and doping concentrations and changing them, the degree of color change can be adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1This is the XRD diagram of the Bi-doped europium salt phosphor prepared in Examples 1-6 of the present invention.

[0016] Figure 2 The actual display shows the color change of the Bi-doped europiumate phosphor prepared in Example 1 of the present invention after being irradiated with 365nm ultraviolet light with a power density of 865 milliwatts per square centimeter for 60 seconds under the shielding of a light-proof material with a hollow square in the middle.

[0017] Figure 3 This is a physical demonstration of the color change of the Bi-doped europiumate phosphor prepared in Example 2 of the present invention after being irradiated with 365nm ultraviolet light with a power density of 865 milliwatts per square centimeter for 60 seconds under the shielding of a light-proof material with a square hollow in the middle.

[0018] Figure 4 This is a physical demonstration of the color change of the Bi-doped europium salt phosphor prepared in Example 3 of the present invention after being irradiated with 365nm ultraviolet light with a power density of 865 milliwatts per square centimeter for 60 seconds under the shielding of a light-proof material with a square hollow in the middle.

[0019] Figure 5 This is a physical demonstration of the color change of the Bi-doped europium salt phosphor prepared in Example 4 of the present invention after being irradiated with 365nm ultraviolet light with a power density of 865 milliwatts per square centimeter for 60 seconds under the shielding of a light-proof material with a square hollow in the middle.

[0020] Figure 6 This is a physical demonstration of the color change of the Bi-doped europium salt phosphor prepared in Example 5 of the present invention after being irradiated with 365nm ultraviolet light with a power density of 865 milliwatts per square centimeter for 60 seconds under the shielding of a light-proof material with a square hollow in the middle.

[0021] Figure 7 This is a physical demonstration of the color change of the Bi-doped europium salt phosphor prepared in Example 6 of the present invention after being irradiated with 365nm ultraviolet light with a power density of 865 milliwatts per square centimeter for 60 seconds under the shielding of a light-proof material with a square hollow in the middle. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the art without making creative work are within the scope of protection of the present invention. Example 1

[0023] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 25% BaCO3, 25% SrCO3, and 0% Bi2O3.

[0024] A preparation method of Bi-doped europium salt phosphor comprises the following steps: placing Eu2O3, BaCO3 and SrCO3 in an agate mortar, adding anhydrous ethanol at a ratio of ethanol volume to powder mass = 5 ml:3 g and grinding for 20 min to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing it in an air atmosphere at a temperature of 1500°C and sintering for 6 h, and cooling it to room temperature to obtain the Bi-doped europium salt phosphor; wherein the heating rate is 5°C / min; and the cooling rate is 3°C / min.

[0025] Depend on Figure 2 It can be seen that the Bi-doped europium salt phosphor prepared in this embodiment changes from white to light gray under ultraviolet light.

[0026] according to Figure 1 It can be seen that the present invention successfully prepared Ba y SrEu4O8:xBi material, and no impurity peak, indicating that the prepared material has high purity. Example 2

[0027] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 24.75% BaCO3, 25% SrCO3, and 0.25% Bi2O3.

[0028] A preparation method of Bi-doped europium salt phosphor comprises the following steps: placing Eu2O3, BaCO3, SrCO3 and Bi2O3 in an agate mortar, adding anhydrous ethanol at a ratio of ethanol volume to powder mass = 5 ml:3 g and grinding for 20 min to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing the mixture in an air atmosphere at a temperature of 1500° C. and sintering for 6 h, and cooling the mixture to room temperature to obtain the Bi-doped europium salt phosphor; wherein the heating rate is 5° C. / min; and the cooling rate is 3° C. / min.

[0029] Depend on Figure 3 It can be seen that the Bi-doped europium salt phosphor prepared in this embodiment changes from light yellow to gray brown under ultraviolet light. Example 3

[0030] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 24.5% BaCO3, 25% SrCO3, and 0.5% Bi2O3.

[0031] A preparation method of Bi-doped europium salt phosphor comprises the following steps: placing Eu2O3, BaCO3, SrCO3 and Bi2O3 in an agate mortar, adding anhydrous ethanol at a ratio of ethanol volume to powder mass = 5 ml:3 g and grinding for 20 min to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing the mixture in an air atmosphere at a temperature of 1500° C. and sintering for 6 h, and cooling the mixture to room temperature to obtain the Bi-doped europium salt phosphor; wherein the heating rate is 5° C. / min; and the cooling rate is 3° C. / min.

[0032] Depend on Figure 4 It can be seen that the Bi-doped europium salt phosphor prepared in this embodiment changes from light yellow to gray brown under ultraviolet light. Example 4

[0033] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 24.25% BaCO3, 25% SrCO3, and 0.75% Bi2O3.

[0034] A preparation method of Bi-doped europium salt phosphor comprises the following steps: placing Eu2O3, BaCO3, SrCO3 and Bi2O3 in an agate mortar, adding anhydrous ethanol at a ratio of ethanol volume to powder mass = 5 ml:3 g and grinding for 20 min to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing the mixture in an air atmosphere at a temperature of 1500° C. and sintering for 6 h, and cooling the mixture to room temperature to obtain the Bi-doped europium salt phosphor; wherein the heating rate is 5° C. / min; and the cooling rate is 3° C. / min.

[0035] Depend on Figure 5 It can be seen that the Bi-doped europium salt phosphor prepared in this embodiment changes from light yellow to gray brown under ultraviolet light. Example 5

[0036] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 24% BaCO3, 25% SrCO3 and 1% Bi2O3.

[0037] A preparation method of Bi-doped europium salt phosphor comprises the following steps: placing Eu2O3, BaCO3, SrCO3 and Bi2O3 in an agate mortar, adding anhydrous ethanol at a ratio of ethanol volume to powder mass = 5 ml:3 g and grinding for 20 min to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing the mixture in an air atmosphere at a temperature of 1500° C. and sintering for 6 h, and cooling the mixture to room temperature to obtain the Bi-doped europium salt phosphor; wherein the heating rate is 5° C. / min; and the cooling rate is 3° C. / min.

[0038] Depend on Figure 6It can be seen that the Bi-doped europium salt phosphor prepared in this embodiment changes from light yellow to gray brown under ultraviolet light. Example 6

[0039] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 23.75% BaCO3, 25% SrCO3, and 1.25% Bi2O3.

[0040] A preparation method of Bi-doped europium salt phosphor comprises the following steps: placing Eu2O3, BaCO3, SrCO3 and Bi2O3 in an agate mortar, adding anhydrous ethanol at a ratio of ethanol volume to powder mass = 5 ml:3 g and grinding for 20 min to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing the mixture in an air atmosphere at a temperature of 1500° C. and sintering for 6 h, and cooling the mixture to room temperature to obtain the Bi-doped europium salt phosphor; wherein the heating rate is 5° C. / min; and the cooling rate is 3° C. / min.

[0041] Depend on Figure 7 It can be seen that the Bi-doped europium salt phosphor prepared in this embodiment changes from light yellow to gray brown under ultraviolet light. Example 7

[0042] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 22.5% BaCO3, 25% SrCO3, and 2.5% Bi2O3.

[0043] A preparation method of Bi-doped europium salt phosphor comprises the following steps: placing Eu2O3, BaCO3, SrCO3 and Bi2O3 in an agate mortar, adding anhydrous ethanol at a ratio of ethanol volume to powder mass = 5 ml:3 g and grinding for 20 min to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing the mixture in an air atmosphere at a temperature of 1500° C. and sintering for 6 h, and cooling the mixture to room temperature to obtain the Bi-doped europium salt phosphor; wherein the heating rate is 5° C. / min; and the cooling rate is 3° C. / min.

[0044] The Bi-doped europium salt phosphor prepared in this embodiment changes from yellow to gray-brown under ultraviolet light. Example 8

[0045] A Bi-doped europiumate phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 24.95% BaCO3, 25% SrCO3, and 0.05% Bi2O3.

[0046] A preparation method of Bi-doped europium salt phosphor comprises the following steps: placing Eu2O3, BaCO3, SrCO3 and Bi2O3 in an agate mortar, adding anhydrous ethanol at a ratio of ethanol volume to powder mass = 3 ml: 3 g and grinding for 10 min to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing the mixture in an air atmosphere at a temperature of 1600° C. and sintering for 4 h, and cooling the mixture to room temperature to obtain the Bi-doped europium salt phosphor; wherein the heating rate is 5° C. / min; and the cooling rate is 1° C. / min.

[0047] The Bi-doped europium salt phosphor prepared in this embodiment changes from white to light gray under ultraviolet light.

[0048] Comparative Example 1

[0049] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 22% BaCO3, 25% SrCO3, and 3% Bi2O3.

[0050] The preparation method of the Bi-doped europium salt phosphor described in this comparative example is the same as that of Example 2.

[0051] The Bi-doped europium phosphor prepared in this comparative example changes from yellow to gray-brown under ultraviolet light, but it takes a longer time to change color under ultraviolet light than in the example. In comparative example 1, excessive Bi doping will lead to excessive defects, and the energy absorbed by the color center will be reduced. In addition, excessive Bi will cause the color of the sample before the color change to become very dark, and the contrast before and after the color change is not obvious.

[0052] Comparative Example 2

[0053] A Bi-doped europium salt phosphor comprises the following raw materials in molar percentage: 50% Eu2O3, 24.995% BaCO3, 25% SrCO3, and 0.005% Bi2O3.

[0054] A preparation method of Bi-doped europium salt phosphor comprises the following steps: grinding Eu2O3, BaCO3, SrCO3 and Bi2O3 in an agate mortar for 20 minutes to obtain a mixed powder; then transferring the mixed powder to a corundum crucible, placing it in an air atmosphere at a temperature of 1500°C and sintering it for 6 hours, and cooling it to room temperature to obtain Bi-doped europium salt phosphor; wherein the heating rate is 5°C / min; and the cooling rate is 3°C / min.

[0055] The Bi-doped europium salt phosphor prepared in this comparative example changes from white to gray-brown under ultraviolet light, but it takes a longer time to change color under ultraviolet light than in the example. In comparative example 2, the raw materials ground without ethanol are not mixed sufficiently, the sample synthesis reaction is not sufficient, and the dispersion of Bi in the sample is not uniform, resulting in a slow photochromic reaction of the material.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A Bi-doped europium phosphor, characterized in that: Its chemical formula is Ba y SrEu4O8:xBi; wherein y is the amount of Ba, 0.95≤y≤0.999, and x is the doping amount of Bi, 0.001<x≤0.05; The preparation method of the Bi-doped europium salt phosphor comprises the following steps: uniformly mixing Eu2O3, BaCO3, SrCO3 and Bi2O3 into mixed powder, adding ethanol, grinding and calcining, and cooling to obtain the Bi-doped europium salt phosphor.

2. The Bi-doped europium phosphor according to claim 1, characterized in that: The ratio of ethanol volume to total mass of mixed powder is 3-8 ml:3 g, and the grinding time is 10-60 min.

3. The Bi-doped europium phosphor according to claim 1, characterized in that: The calcination temperature is 1500-1600°C, the time is 4-20 hours, and the calcination atmosphere is air.

4. The Bi-doped europium phosphor according to claim 1, characterized in that: The cooling rate is 1~3℃ / min.

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