A Cu 2+ -Li + co-doped gallate fluorescent material: preparation and applications

Abstract

The present invention discloses a Cu<supgt;2+< / supgt> - Li<supgt;+< / supgt> co-doped gallate fluorescent material with tunable afterglow. This material is a novel optical material with a wide emission band (~230 nm) and long afterglow performance (~20 min). In addition, with the addition of Li<supgt;+< / supgt>, the emission intensity is enhanced (6.62 times), the defect concentration is increased (3.6 times), and the afterglow time is extended (~20 min), thus realizing the process of tunable afterglow. The afterglow modulation defect engineering strategy in the present invention may further inspire innovative ideas for the preparation of high-performance optical information storage and encryption high-performance long afterglow materials.

Description

Technical Field

[0001] The invention relates to the field of solid luminescent materials, and in particular to a method for preparing fluorescent powder that can be used for optical information storage and encryption. Background Art

[0002] With the rapid development of the information age, people are increasingly concerned about the pitfalls of information security, and storing and encrypting information in a more secure way is an increasingly urgent need. Therefore, materials with optical information storage and anti-counterfeiting properties have received widespread attention. Optical information storage has the advantages of low energy consumption, long life, and large capacity, and plays an indispensable role in modern information storage networks. Due to the limitations of two-dimensional spatial resolution, optical discs, digital video discs, and Blu-ray discs are facing more and more challenges. In addition, due to the lack of suitable optical storage media, practical applications are still difficult. Therefore, the development of new advanced optical materials must meet the needs of modern information storage.

[0003] Persistent luminescent phosphors can store light energy in advance and then release persistent afterglow emission. Long afterglow luminescent materials have unique energy storage and controlled photon release properties under additional stimulation, thus achieving high-capacity storage in next-generation information storage systems. However, the lack of suitable tunable long afterglow luminescent materials is a bottleneck for this type of storage technology. Currently, most of the long afterglow phosphors used for optical information storage and encryption form an interpretation of "writing" and "reading" of information storage with a single afterglow effect or multi-color effect in the emission band. For example: BaGa2O4:Bi 3+ 、Li2CaSiO4:Pr 3+ Etc. Therefore, the prior art needs to be improved. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a Cu 2+ -Li + The co-doped gallate fluorescent material and the preparation method thereof are intended to solve the problems raised in the above background technology.

[0005] The present invention provides a copper-lithium Cu with adjustable afterglow 2+ -Li + Co-doped gallate fluorescent material, its chemical formula is: MGaO2:xCu 2+ ,yLi + , where M is a monovalent metal, x and y represent Cu 2+ and Li + The molar fraction of , 0.0005≤x≤0.012, 0≤y≤0.03;

[0006] The afterglow adjustable copper-lithium Cu 2+-Li + The crystal structure of the co-doped gallate fluorescent material is based on NaGaO2 and the doping component is Cu 2+ and Li + , Cu 2+ Substituting Ga in the matrix 3+ The case, Li + Substituents in the matrix + the case of;

[0007] The afterglow is adjustable means that by adjusting the Cu 2+ -Li + Doping amount to adjust the afterglow time;

[0008] The copper-lithium Cu with adjustable afterglow 2+ -Li + When excited by 355-nanometer ultraviolet light, the co-doped gallate fluorescent material has a strongest emission peak at 585 nanometers, a half-peak width of about 230 nanometers, and an afterglow duration of 1 to 20 minutes.

[0009] Preferably, the monovalent metal M is any one or more combinations of sodium, potassium and cesium.

[0010] The present invention also provides a Cu with adjustable afterglow 2+ -Li + A method for preparing a co-doped gallate fluorescent material, characterized in that it comprises the following steps:

[0011] Step (1), according to the chemical formula MGaO2:xCu 2+ ,yLi + The molar ratio of M, Ga, Cu and Li elements in the mixture is: a compound containing M ions, a compound containing gallium ions, a compound containing copper ions and a compound containing lithium ions are weighed as raw materials, wherein M is a monovalent metal, 0.0005≤x≤0.012, 0≤y≤0.03;

[0012] Step (2), mixing and fully grinding the raw materials weighed in step (1), and then pre-calcining;

[0013] Step (3), the product obtained by pre-sintering in step (2) is naturally cooled to room temperature, and after being fully and evenly ground again, sintered. After the sintering process is completed, it is naturally cooled to room temperature to obtain Cu 2+ -Li + Co-doped gallate phosphors.

[0014] Preferably, the compound containing M ions includes any one or more combinations of M metal oxides, M metal hydroxides, and M metal carbonate compounds;

[0015] The gallium ion-containing compound is Ga2O3, and the copper ion-containing compound is CuO;

[0016] The lithium ion-containing compound is any one or a combination of Li2CO3 and LiF2.

[0017] Preferably, the pre-sintering is carried out in an air atmosphere, the temperature of the pre-sintering is 400 - 800 °C, and the time of the pre-sintering is 4 - 8 hours.

[0018] Preferably, the sintering is carried out in an air atmosphere, the temperature of the sintering is 1000 - 1500 °C, and the time of the sintering is 5 - 12 hours.

[0019] The present invention also provides a method for adjusting the afterglow of a Cu 2+ -Li + co-doped gallate fluorescent material. The Cu 2+ -Li co-doped gallate fluorescent material is obtained according to the preparation method; in step (1), x is set to 0.001; the afterglow time of the product is adjusted by adjusting the doping amount of lithium ions in step (1).

[0020] Preferably, the doping amount of lithium ions is adjusted in the following manner to control the afterglow time of the product:

[0021] When y is 0, the afterglow time of the product is 5 - 15 seconds;

[0022] When y is 0.005, the afterglow time of the product is 14 - 16 minutes;

[0023] When y is 0.01, the afterglow time of the product is 19 - 21 minutes;

[0024] When y is 0.02, the afterglow time of the product is 14 - 16 minutes;

[0025] When y is 0.03, the afterglow time of the product is 9 - 11 minutes.

[0026] The present invention also provides a method for information storage and encryption using the afterglow adjustment method described above. Two types of gallate fluorescent materials with different afterglow times are prepared according to a preset lithium ion doping concentration; the information to be encrypted is obtained, and the two types of gallate fluorescent materials with different afterglow times are used to encode the information to be encrypted to complete information storage and encryption; ultraviolet light in the wavelength range of 355 - 365 nm is used to excite the two types of gallate fluorescent materials with a large difference in afterglow time, and the afterglow time of the gallate fluorescent materials is recorded, and decoding is performed based on the afterglow time to obtain the information to be encrypted.

[0027] Table 1: Cu 2+ -Li + Summary table of the regulation of afterglow by co-doping.

[0028]

[0029] Beneficial effects: The present invention proposes a copper-lithium Cu 2+ -Li + co-doped gallate fluorescent material, which is a new type of optical material with a wide emission band (~230 nm) and long afterglow performance (~20 min). In addition, with the addition of Li + , the emission intensity is enhanced by about 6.62 times, the defect concentration increases by 3.6 times, and the afterglow time is extended by about 20 minutes. More importantly, by adjusting, the length of the afterglow before and after is different, and the material can achieve a new type of optical information storage and encryption. The afterglow modulation defect engineering strategy in the present invention may further inspire innovative ideas for preparing high-performance optical information storage and encryption high-performance long-afterglow materials. Description of the Drawings

[0030] Figure 1 Emission spectrum of the phosphor prepared according to Example 1 under 355-nm ultraviolet light excitation;

[0031] Figure 2 Emission spectrum intensity comparison chart of two types of phosphors prepared according to Examples 1 and 2 with / without lithium ion doping under 355-nm ultraviolet light excitation;

[0032] Figure 3 CIE coordinate comparison chart of two types of phosphors prepared according to Examples 1 and 2 with / without lithium ion doping;

[0033] Figure 4 Thermoluminescence spectrum chart of two types of phosphors prepared according to Examples 1 and 2 with / without lithium ion doping;

[0034] Figure 5 Afterglow comparison chart of two types of phosphors prepared according to Examples 1 and 2 with / without lithium ion doping taken by a camera;

[0035] Figure 6 Schematic diagram of the application in the field of optical information storage and encryption. Detailed Embodiments

[0036] The present invention will be analyzed in detail below in combination with specific embodiments. The following embodiments are intended to illustrate the present invention, and any improvements and changes made on the basis of the present invention are within the protection scope of the present invention.

[0037] A copper-lithium Cu with adjustable afterglow 2+-Li + Co-doped gallate fluorescent material, characterized in that the matrix of the fluorescent material is metal gallate, and the doping component includes Cu 2+ and Li + . Characterized in that the doped Cu 2+ The molar percentage of Li is [0.0005, 0.012], and the doped Li + The molar percentage of Li is [0,0.03]. + The afterglow effect changes. By adjusting Cu 2+ and Li + The doping concentration can realize optical information storage and encryption.

[0038] The preparation method used in the above technical solution adopts a high temperature solid phase sintering method, based on the following steps:

[0039] Step (1), using a compound containing sodium ions, a compound containing gallium ions, a compound containing copper ions, and a compound containing lithium ions as raw materials, according to the chemical formula NaGaO2:xCu 2+ ,yLi + The stoichiometric ratio of each element in the mixture is weighed; where x is the copper ion Cu 2+ The molar percentage of doping is 0.0005≤x≤0.012; y is the lithium ion Li + The molar percentage of doping is 0.005≤y≤0.03;

[0040] Step (2), mixing and fully grinding the powders weighed in step (1), putting them into a crucible after grinding evenly, and pre-calcining them in an air atmosphere at a temperature of 400-800° C. for a pre-calcining time of 4-8 hours;

[0041] Step (3), the mixture obtained after pre-sintering in step (2) is naturally cooled to room temperature, and then fully and evenly ground again, and sintered in an air atmosphere at a sintering temperature of 1000-1500°C for 5-12 hours. After the sintering process is completed, the mixture is naturally cooled to room temperature to obtain a chemical formula of NaGaO2:xCu 2+ ,yLi + Gallate phosphors with long afterglow performance;

[0042] Furthermore, the compound containing sodium ions in step (1) is one or more of Na2CO3 and NaOH; the compound containing gallium ions in step (1) is Ga2O3; the compound containing copper ions in step (1) is CuO; the compound containing lithium ions in step (1) is one or more of Li2CO3 and LiF2.

[0043] Example 1: Preparation of NaGaO2:0.001Cu 2+ phosphor.

[0044] Weigh Na2CO3: 15.9 g, Ga2O5: 28.11 g, and CuO: 0.24 g respectively according to the stoichiometric ratios of the elements in the chemical formula NaGaO2:0.001Cu 2+ 2+ 2+ .

[0045] Place them in an agate mortar, grind them thoroughly and evenly, then put them in a crucible, pre-burn them in an air atmosphere at a pre-burning temperature of 400 °C for 8 hours. After natural cooling to room temperature, grind them again and then calcine them in an air atmosphere at a calcination temperature of 1100 °C for 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.001Cu is obtained

[0046] Example 2: Preparation of NaGaO2:0.001Cu 2+ , 0.01Li + phosphor

[0047] Weigh Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.024 g, and Li2CO3: 0.044 g respectively according to the stoichiometric ratios of the elements in the chemical formula NaGaO2:0.001Cu 2+ , 0.01Li + 2+ + , 0.01Li + .

[0048] Characterize the fluorescence spectrum of this phosphor by a fluorescence spectrometer. The emission peaks of copper ions can be detected. The peak intensity is at 585 nm, the full width at half maximum is 220 nm, and the afterglow duration is about 20 minutes

[0049] When this phosphor is excited by a 355-nm ultraviolet excitation light source, emission spectra with different emission intensities of this phosphor can be obtained( Figure 1)。By preparing a series of lithium-ion-doped phosphors and comparing their emission intensities with the phosphor prepared in Example 1, it is found that the emission intensity of the phosphor after lithium-ion treatment is increased by up to 6.62 times ( Figure 2 )。At the same time, by comparing the CIE chromaticity coordinates of the two phosphors, it can be obtained that the color does not change significantly before and after treatment, which also provides a prerequisite for the subsequent application of the phosphor. Figure 3 )。The thermoluminescence spectra of the two prepared phosphors were tested, and the changes in the trap energy levels of the phosphors before and after Li + treatment were confirmed. The phenomenon of the afterglow change of the two phosphors within 20 minutes can be clearly observed. Figure 4 , Figure 5 )。According to the unique properties and effects of the prepared phosphors, a new type of optical information storage and encryption method was realized. Figure 6 )。Since the emissions of NaGaO2:xCu 2+ and NaGaO2:xCu 2+ ,yLi + are almost the same (excited by 365 nm ultraviolet light), but their long afterglow characteristics are different. The production mode of the dynamic photoluminescence mode without any irradiation treatment is designed and given. There is no obvious signal output under sunlight, which is the initial state of the model. The luminous points and non-luminous points represent the codes "8" and "H" respectively. When the pattern is exposed to 365 nm light, the luminous array is clearly visible, and the letter data "888" is output, marked as optical information 1. The specially treated sample also produced "888" under 365 nm ultraviolet light irradiation. However, after removing the light source, the optical information 2 "HDU" is displayed. As shown by the different patterns prepared with the sample NGO:0.001Cu2+, 1% Li+. Obviously, the prepared template does not show any detectable photon emission under sunlight and emits orange-yellow light under 365 nm ultraviolet light. After removing the light source, the pattern maintains the afterglow effect for a period of time. Moreover, it can re-emit light after heating. This is a typical optical information storage phenomenon. Table 1 records the afterglow conditions of a series of samples doped with different concentrations of Cu 2+ and Li + . It is concluded that the sample NaGaO2:0.001Cu 2+ , 0.01Li + is the optimal sample of this tunable long afterglow phosphor.

[0050] Example 3: Preparation of NaGaO2:0.001Cu 2+ , 0.005Li + phosphor

[0051] According to the chemical general formula NaGaO2:0.001Cu 2+ , 0.005Li+ For the stoichiometric ratios of the elements in + , weigh out Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.024 g, and Li2CO3: 0.022 g respectively and place them in an agate mortar for sufficient and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After naturally cooling to room temperature, grind again and then calcine in an air atmosphere. The calcination temperature is 1100 °C and the time is 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.001Cu 2+ , 0.005Li + .

[0052] Characterize the fluorescence spectrum of the phosphor by a fluorescence spectrometer, and the emission peaks generated by copper ions can be detected. The peak position of the highest intensity is at 585 nm, the full width at half maximum is 220 nm, and the afterglow duration is about 15 minutes.

[0053] Example 4: Preparation of NaGaO2:0.001Cu 2+ , 0.02Li + phosphor

[0054] According to the stoichiometric ratios of the elements in the chemical general formula NaGaO2:0.001Cu 2+ , 0.02Li + weigh out Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.024 g, and Li2CO3: 0.088 g respectively and place them in an agate mortar for sufficient and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After naturally cooling to room temperature, grind again and then calcine in an air atmosphere. The calcination temperature is 1100 °C and the time is 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.001Cu 2+ , 0.02Li + .

[0055] Characterize the fluorescence spectrum of the phosphor by a fluorescence spectrometer, and the emission peaks generated by copper ions can be detected. The peak position of the highest intensity is at 585 nm, the full width at half maximum is 220 nm, and the afterglow duration is about 15 minutes.

[0056] Example 5: Preparation of NaGaO2:0.001Cu 2+ , 0.03Li + phosphor

[0057] According to the stoichiometric ratios of the elements in the chemical general formula NaGaO2:0.001Cu 2+ , 0.03Li +For the stoichiometric ratios of the elements in [the compound], weigh out Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.024 g, and Li2CO3: 0.132 g respectively and place them in an agate mortar for thorough and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After natural cooling to room temperature, grind again and then calcine in an air atmosphere. The calcination temperature is 1100 °C and the time is 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.001Cu 2+ , 0.03Li + .

[0058] Characterize the fluorescence spectrum of this phosphor through a fluorescence spectrometer, and the emission peak generated by copper ions can be detected. The peak position of the highest intensity is at 585 nm, the full width at half maximum is 220 nm, and the afterglow duration is about 10 minutes.

[0059] Example 6: Preparation of NaGaO2:0.0005Cu 2+ , 0.01Li + phosphor

[0060] According to the chemical general formula NaGaO2:0.0005Cu 2+ , 0.01Li + For the stoichiometric ratios of the elements in [the compound], weigh out Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.012 g, and Li2CO3: 0.044 g respectively and place them in an agate mortar for thorough and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After natural cooling to room temperature, grind again and then calcine in an air atmosphere. The calcination temperature is 1100 °C and the time is 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.0005Cu 2+ , 0.01Li + .

[0061] Characterize the fluorescence spectrum of this phosphor through a fluorescence spectrometer, and the emission peak generated by copper ions can be detected. The peak position of the highest intensity is at 585 nm, the full width at half maximum is 200 nm, and the afterglow duration is about 12 minutes.

[0062] Example 7: Preparation of NaGaO2:0.005Cu 2+ , 0.01Li + phosphor

[0063] According to the chemical general formula NaGaO2:0.0005Cu 2+ , 0.01Li +For the stoichiometric ratios of the elements in [the compound], weigh out Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.12 g, and Li2CO3: 0.044 g respectively and place them in an agate mortar for thorough and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After natural cooling to room temperature, conduct re-grinding and then burn in an air atmosphere. The burning temperature is 1150 °C and the time is 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.005Cu 2+ , 0.01Li + .

[0064] Characterize the fluorescence spectrum of this phosphor through a fluorescence spectrometer. The emission peaks generated by copper ions can be detected. The peak intensity is at its highest at 585 nm, the full width at half maximum is 205 nm, and the afterglow duration is approximately 15 minutes.

[0065] Example 8: Preparation of NaGaO2:0.008Cu 2+ , 0.01Li + phosphor

[0066] According to the chemical general formula NaGaO2:0.008Cu 2+ , 0.01Li + For the stoichiometric ratios of the elements in [the compound], weigh out Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.192 g, and Li2CO3: 0.044 g respectively and place them in an agate mortar for thorough and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After natural cooling to room temperature, conduct re-grinding and then burn in an air atmosphere. The burning temperature is 1100 °C and the time is 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.008Cu 2+ , 0.01Li + .

[0067] Characterize the fluorescence spectrum of this phosphor through a fluorescence spectrometer. The emission peaks generated by copper ions can be detected. The peak intensity is at its highest at 585 nm, the full width at half maximum is 208 nm, and the afterglow duration is approximately 12 minutes.

[0068] Example 9: Preparation of NaGaO2:0.01Cu 2+ , 0.01Li + phosphor

[0069] According to the chemical general formula NaGaO2:0.01Cu 2+ , 0.01Li +For the stoichiometric ratios of the elements in [the compound], weigh out Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.24 g, and Li2CO3: 0.044 g respectively and place them in an agate mortar for thorough and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After natural cooling to room temperature, grind again and then calcine in an air atmosphere. The calcination temperature is 1100 °C and the time is 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.01Cu 2+ , 0.01Li + is obtained.

[0070] Characterize the phosphor by a fluorescence spectrometer for its fluorescence spectrum. The emission peaks generated by copper ions can be detected. The peak intensity is the highest at 585 nm, the full width at half maximum is 210 nm, and the afterglow duration is about 10 minutes.

[0071] Example 10: Preparation of NaGaO2:0.012Cu 2+ , 0.01Li + phosphor

[0072] According to the chemical general formula NaGaO2:0.012Cu 2+ , 0.01Li + For the stoichiometric ratios of the elements in [the compound], weigh out Na2CO3: 1.59 g, Ga2O5: 2.811 g, CuO: 0.288 g, and Li2CO3: 0.044 g respectively and place them in an agate mortar for thorough and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After natural cooling to room temperature, grind again and then calcine in an air atmosphere. The calcination temperature is 1100 °C and the time is 5 hours. When the furnace temperature naturally cools to room temperature, the target product NaGaO2:0.012Cu 2+ , 0.01Li + is obtained.

[0073] Characterize the phosphor by a fluorescence spectrometer for its fluorescence spectrum. The emission peaks generated by copper ions can be detected. The peak intensity is the highest at 585 nm, the full width at half maximum is 215 nm, and the afterglow duration is about 10 minutes.

[0074] Example 11: Preparation of KGaO2:0.001Cu 2+ , 0.01Li + phosphor

[0075] According to the chemical general formula KGaO2:0.001Cu 2+ , 0.01Li +For the stoichiometric ratios of the elements in it, weigh out K2CO3: 1.36 g, Ga2O5: 2.811 g, CuO: 0.024 g, and Li2CO3: 0.044 g respectively and place them in an agate mortar for sufficient and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After natural cooling to room temperature, grind again and then calcine in an air atmosphere. The calcination temperature is 1200 °C and the time is 6 hours. When the furnace temperature naturally cools to room temperature, the target product KGaO2:0.001Cu 2+ , 0.01Li + .

[0076] Example 12: Preparation of KGaO2:0.01Cu 2+ , 0.01Li + phosphor

[0077] According to the chemical general formula KGaO2:0.01Cu 2+ , 0.01Li + For the stoichiometric ratios of the elements in it, weigh out K2CO3: 1.36 g, Ga2O5: 2.811 g, CuO: 0.24 g, and Li2CO3: 0.044 g respectively and place them in an agate mortar for sufficient and uniform grinding. Then place them in a crucible and pre-burn in an air atmosphere. The pre-burning temperature is 400 °C and the time is 5 hours. After natural cooling to room temperature, grind again and then calcine in an air atmosphere. The calcination temperature is 1200 °C and the time is 6 hours. When the furnace temperature naturally cools to room temperature, the target product KGaO2:0.01Cu 2+ , 0.01Li + .

[0078] The above embodiments are not limitations on the present invention. The present invention is not limited to the above embodiments. As long as it meets the requirements of the present invention, it belongs to the protection scope of the present invention.

Claims

1. A Cu 2+ -Li + co-doped gallate fluorescent material, characterized in that Its chemical general formula is: MGaO2:xCu 2+ , yLi + , where M is a monovalent metal Na, 0.0005 ≤ x ≤ 0.012, 0 ≤ y ≤ 0.03; The Cu with adjustable afterglow 2+ -Li + The crystal structure of the co-doped gallate fluorescent material is based on NaGaO2, and the doping components are Cu 2+ and Li + , Cu 2+ substitutes the lattice site of Ga in the matrix 3+ , Li + substitutes the lattice site of M in the matrix + ; The adjustable afterglow means that the afterglow time is adjusted by adjusting the doping amount of the Cu 2+ -Li + doping amount; The above-mentioned Cu 2+ -Li + The co-doped gallate fluorescent material, when excited by 355-nm ultraviolet light, has its strongest emission peak at 585 nm, a half-peak width of 230 nm, and an afterglow duration of 1 minute to 20 minutes.

2. A preparation method of a Cu 2+ -Li + co-doped gallate fluorescent material with adjustable afterglow, characterized in that It includes the following steps: Step (1): According to the molar ratios of elements M, Ga, Cu, and Li in the chemical formula MGaO₂: xCu 2+ , yLi + , weigh out compounds containing M ions, compounds containing gallium ions, compounds containing copper ions, and compounds containing lithium ions as raw materials respectively, where M is a monovalent metal Na, 0.0005 ≤ x ≤ 0.012, and 0 ≤ y ≤ 0.03; Step (2): After mixing and thoroughly grinding the raw materials weighed in step (1), pre-sintering is carried out. Step (3): Naturally cool the product obtained by pre-burning in step (2) to room temperature. After grinding it sufficiently and evenly again, perform sintering. After the sintering process ends, wait for it to naturally cool to room temperature to obtain Cu 2+ -Li + co-doped gallate phosphor.

3. The preparation method of a Cu 2+ -Li + co-doped gallate fluorescent material with adjustable afterglow, characterized in that The compound containing M ions includes any one or a combination of multiple of M metal oxides, M metal hydroxides, and M metal carbonate compounds. The compound containing gallium ions is Ga2O3, and the compound containing copper ions is CuO. The compound containing lithium ions is any one or a combination of multiple of Li2CO3 and LiF2.

4. A preparation method of a Cu 2+ -Li + co-doped gallate fluorescent material with adjustable afterglow, characterized in that, The pre-sintering is carried out in an air atmosphere. The temperature of the pre-sintering is 400 - 800 °C, and the time of the pre-sintering is 4 - 8 hours.

5. A preparation method of a Cu 2+ -Li + co-doped gallate fluorescent material with adjustable afterglow, characterized in that The sintering is carried out in an air atmosphere. The temperature of the sintering is 1000 - 1500 °C, and the time of the sintering is 5 - 12 hours.

6. A kind of Cu 2+ -Li + Afterglow adjustment method of co-doped gallate fluorescent material, the Cu 2+ -Li + The co-doped gallate fluorescent material is obtained by the preparation method according to claim 2; Characterized in that, In step (1), x is set to 0.001; the afterglow time of the product is adjusted by adjusting the doping amount of lithium ions in step (1).

7. A method for adjusting the afterglow of a Cu 2+ -Li + co-doped gallate fluorescent material, characterized in that, The doping amount of lithium ions is adjusted in the following way to control the afterglow time of the product: When y is 0, the afterglow time of the product is 5 - 15 seconds; When y is 0.005, the afterglow time of the product is 14 - 16 minutes; When y is 0.01, the afterglow time of the product is 19 - 21 minutes; When y is 0.02, the afterglow time of the product is 14 - 16 minutes; When y is 0.03, the afterglow time of the product is 9 - 11 minutes.

8. A method for information storage and encryption using the afterglow adjustment method according to claim 7, characterized in that, Two types of gallate fluorescent materials with different afterglow times are prepared according to the preset lithium ion doping concentration. The information to be encrypted is obtained, and the two types of gallate fluorescent materials with different afterglow times are used to encode the information to be encrypted, completing information storage and encryption. Ultraviolet light in the wavelength range of 355 - 365 nm is used to excite the two types of gallate fluorescent materials with different afterglow times, and the afterglow time of the gallate fluorescent materials is recorded, and decoding is carried out based on the afterglow time to obtain the information to be encrypted.

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