Gallate scintillator long-afterglow luminescent material excited by X-ray and UV (ultraviolet) and preparation method of gallate scintillator long-afterglow luminescent material

Abstract

The invention discloses a gallate scintillator long-afterglow luminescent material capable of being excited by X rays and UV (ultraviolet) and a preparation method of the gallate scintillator long-afterglow luminescent material. The chemical formula of the material is CaGa2O4: x% Tb < 3 + >, y% Li < + >, 0.3 < = x < = 1.5, and 0 < = y < = 7. The preparation method comprises the following steps: respectively weighing raw materials according to a stoichiometric ratio, uniformly mixing to obtain precursor powder, calcining, cooling to room temperature, and grinding again to obtain the gallate scintillator long-afterglow luminescent material. The material has the advantages of long afterglow time, high luminance and the like under excitation of ultraviolet light and X rays, and the preparation method is simple, free of pollution, low in cost and suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of luminescent materials and relates to a scintillator luminescent material, in particular to a gallate scintillator long afterglow luminescent material excited by X-rays and UV ultraviolet light and a preparation method thereof. Background Art

[0002] Long afterglow luminescence is a unique optical process that continues to emit light for seconds or even hours after the excitation stops. Scintillator long afterglow luminescent materials are long afterglow luminescent materials that can absorb X-rays and store their energy, and continue to emit visible light or near-infrared light after the excitation stops. Because of this unique property, scintillator long afterglow luminescent materials have surpassed other types of luminescent materials in a variety of application fields such as high-contrast bioimaging, high-resolution X-ray detection, and X-ray-induced photodynamic therapy (X-PDT), and therefore are receiving increasing research attention in various fields.

[0003] At present, the reported scintillator long afterglow luminescent materials include: Patent "A long afterglow material that can be excited by X-rays and its application" (application number 201610978260.5) discloses a long afterglow material that can be excited by X-rays, with a maximum duration of 2000 seconds; Patent "X-ray-excited photodynamic anti-cancer nanocomposite particles and preparation method thereof" (application number 202111458723.2) discloses an X-ray-excited photodynamic anti-cancer nanocomposite particle and its preparation method, which belongs to the field of medical technology, and the afterglow time is not reported; Patent "A type of full-spectrum multi-color long afterglow fluorescent material at low temperature of 77K and its preparation method" (application number 202410156158.1) discloses a rare earth-doped double Perovskite material is a phosphor that can emit light for up to 2 hours after being irradiated by X-rays at a temperature of 77K; Patent "A rare earth element doped pyrophosphate long afterglow material that can only be excited by X-rays and its preparation method and application" (Application No. 202410362486.7) discloses a long afterglow material that can only be excited by X-rays and cannot be excited by white light and ultraviolet light, and the afterglow duration can reach at least 4000 seconds; Patent "A new type of X-ray excited long afterglow nanoparticle-photosensitizer coupling system and its preparation method" (Application No. 202410424778.9) discloses a new type of X-ray excited long afterglow nanoparticle-photosensitizer coupling system, which belongs to the field of biomedical materials technology. This NaYF4 : The afterglow time of Tb@NaYF4 long afterglow nanoparticles can reach 90 minutes; the patent "A borate long afterglow luminescent material excited by X-rays and its preparation method" (application number 202410696431.X) discloses a borate long afterglow luminescent material that can be excited by X-rays, and the afterglow duration can reach at least 5400 seconds. The afterglow time and afterglow brightness of the above scintillator long afterglow luminescent materials are still poor, so it is necessary to develop new scintillator long afterglow materials with excellent afterglow performance. Summary of the invention

[0004] The object of the present invention is to provide a gallate scintillator long afterglow luminescent material excited by X-rays and UV ultraviolet light, the chemical formula of the luminescent material is CaGa2O4: x%Tb 3+ , y%Li + ; Among them, 0.3≤x≤1.5, 0≤y≤7.

[0005] Furthermore, the chemical formula of the luminescent material is CaGa2O4: x%Tb 3+ ; The values ​​of x are 0.3, 0.6, 0.9, 1.2, and 1.5.

[0006] Furthermore, the chemical formula of the luminescent material is CaGa2O4: 1.2%Tb 3+ , y%Li +; The values ​​of y are 1, 2, 3, 5, 7.

[0007] The luminescence mechanism of the present invention: When 254nm ultraviolet light irradiates CaGa2O4: Tb 3+ , Li + When the ultraviolet light source is removed, the trapped electrons absorb energy under the action of thermal disturbance at room temperature, break free from the bondage and return to the conduction band, and then jump to the luminescence center Tb 3+ The excited state of the ion occurs 5 D4→ 7 F J (J = 6, 5, 4, 3) energy level transitions, generating 486nm, 543nm, 588nm and 624nm Tb 3+ The electrons captured in shallow traps are released quickly, which determines the initial brightness of the material, while the electrons captured in deep traps are released slowly, which determines the afterglow duration of the material. + The co-doping of ions effectively regulates the defect structure in the material and significantly increases the concentration of shallow traps, which significantly improves the initial brightness and afterglow time of the afterglow under ultraviolet excitation. The luminescence mechanism of the material under X-ray excitation is different from that under ultraviolet excitation. When X-rays irradiate the material, high-energy free electrons are ionized due to the photoelectric effect and the Compton effect. These electrons collide with other atoms in the material to produce secondary electrons. After losing kinetic energy, the free electrons reach the bottom of the conduction band and are then captured by electron traps, thereby producing long afterglow luminescence. At the same time, when X-rays irradiate the material, a variety of new defect structures different from the inherent defect structure of the material are generated, which makes the afterglow luminescence performance excited by X-rays different from that excited by ultraviolet light.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned gallate scintillator long afterglow luminescent material. The method comprises the following steps: 1) According to the chemical formula CaGa2O4: x%Tb 3+ , y%Li + According to the stoichiometric ratio of each element in the formula, Ga2O3, CaCO3, Tb(NO3)3 or Tb4O7 and Li2CO3 are weighed as raw materials respectively; 2) Place the weighed raw materials in an agate mortar, add anhydrous ethanol, grind for 1-2 hours to mix evenly, and obtain a precursor powder; the amount of anhydrous ethanol added is 400%-600% of the total weight of the raw material mixture; 3) Place the precursor powder in a corundum crucible, put it in a Muffle furnace, heat it to 1100~1300℃ at a heating rate of 5℃ / min in an air atmosphere, calcine it for 3~6h, cool it naturally to room temperature, obtain the calcined product, grind it, and prepare the gallate scintillator long afterglow luminescent material.

[0009] The present invention has the following beneficial effects: 1) The preparation method of the gallate scintillator long afterglow luminescent material of the present invention is simple, efficient, has no waste water or waste gas emissions, is environmentally friendly, and is suitable for industrial and continuous production; 2) The gallate scintillator long afterglow luminescent material prepared by the present invention has the characteristics of long afterglow time and high brightness after being excited by UV light or X-rays for a short time; 3) Tb 3+ The long afterglow luminescent material of the doped gallate scintillator emits bright green afterglow after being excited by UV light or X-rays. The afterglow peak is Tb 3+ Ion linear characteristic emission, the main peak is located at 543nm, and the color coordinates are located near (0.323, 0.4743); Synthesized CaGa2O4: 1.2%Tb 3+ , 2%Li + After being excited by X-rays, the afterglow lasts for more than 1 hour, with an initial intensity of 966948 counts, which decays to 1% of the initial intensity after 1 hour. After being excited by UV light, the afterglow lasts for up to 7 hours, and the initial brightness of the afterglow can reach 0.1594 cd / m 2 ; 4) The gallate scintillator long afterglow luminescent material prepared by the present invention can be mixed with polymer materials such as epoxy resin and curing agent to form a flexible film, which can be used as a luminescent flexible film or a green afterglow luminescent device, and has good application prospects in high-level anti-counterfeiting, photodynamic therapy, biological imaging and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The gallate scintillator long afterglow luminescent material CaGa2O4: x%Tb prepared in Example 1 3+ (x=0, 0.3, 0.6, 0.9, 1.2, 1.5) and the standard PDF#01-073-6109 card diffraction pattern of CaGa2O4.

[0011] Figure 2 The gallate scintillator long afterglow luminescent material CaGa2O4: x%Tb prepared in Example 1 3+ Emission spectra of (x=0.3, 0.6, 0.9, 1.2, 1.5) under 242nm UV excitation; the inset shows the emission intensity of the series of samples at 543nm and Tb 3+ The relationship between concentration.

[0012] Figure 3 The gallate scintillator long afterglow luminescent material CaGa2O4: x%Tb prepared in Example 1 3+ (x=0.3, 0.6, 0.9, 1.2, 1.5) Afterglow luminescence intensity decay curve under UV light excitation.

[0013] Figure 4 The gallate scintillator long afterglow luminescent material CaGa2O4: x%Tb prepared in Example 1 3+ (x=0.3, 0.6, 0.9, 1.2, 1.5) Thermoluminescence spectra under UV light excitation.

[0014] Figure 5 The gallate scintillator long afterglow luminescent material CaGa2O4 prepared in Example 2: 1.2% Tb 3+ , y%Li + (y=0, 1, 2, 3, 5, 7) and PDF#01-073-6109 standard card diffraction pattern.

[0015] Figure 6 The gallate scintillator long afterglow luminescent material CaGa2O4 prepared in Example 2: 1.2% Tb 3+ ,y%Li + (y=0, 1, 2, 3, 5, 7) emission spectra under 242nm ultraviolet excitation; the inset shows the emission intensity of the series of samples at 543nm and Li + The relationship between concentration.

[0016] Figure 7 The gallate scintillator long afterglow luminescent material CaGa2O4 prepared in Example 2: 1.2% Tb 3+ , y%Li + (y=0, 1, 2, 3, 5, 7) Afterglow decay curve under UV light excitation.

[0017] Figure 8 The gallate scintillator long afterglow luminescent material CaGa2O4 prepared in Example 2: 1.2% Tb 3+ , y%Li + (y=0, 1, 2, 3, 5, 7) Thermoluminescence spectra under UV light excitation.

[0018] Fig. 9 The gallate scintillator long afterglow luminescent material CaGa2O4 prepared in Example 2: 1.2% Tb 3+ , 2%Li + Emission spectrum under X-ray excitation.

[0019] Fig.10 The gallate scintillator long afterglow luminescent material CaGa2O4 prepared in Example 2: 1.2% Tb 3+ , 2%Li + Afterglow luminescence decay curve after 3 minutes of X-ray excitation.

[0020] Fig.11 The gallate scintillator long afterglow luminescent material CaGa2O4 prepared in Example 2: 1.2% Tb 3+ , 2%Li + The photo was taken by the mobile phone after being excited by 254nm UV light and X-rays.

[0021] Fig.12 The gallate scintillator long afterglow luminescent material CaGa2O4 prepared in Example 2: 1.2% Tb 3+ , 2%Li + Thermoelectric spectra under UV light and X-ray excitation at room temperature and low temperature.

[0022] In the above figures, CGO represents CaGa2O4. DETAILED DESCRIPTION

[0023] The present invention is further explained below with reference to specific embodiments.

[0024] Example 1 According to the molecular formula CaGa2O4: x%Tb 3+ According to the stoichiometric ratio shown in (x=0, 0.3, 0.6, 0.9, 1.2, 1.5), 300.27 mg of CaCO3, 562.32 mg of Ga2O3 and 3.104~15.522 mg of Tb(NO3)3 were weighed respectively, the above raw materials were placed in an agate mortar, anhydrous ethanol was added and ground until mixed uniformly to obtain a precursor powder, the precursor powder was transferred to a corundum crucible, placed in a muffle furnace, and calcined at a temperature of 1100~1300℃ in an air atmosphere at a heating rate of 5℃ / min for 3~6h, and naturally cooled to room temperature to obtain a calcined product, and the calcined product obtained by grinding was prepared as a gallate scintillator long afterglow luminescent material.

[0025] Product structure characterization and performance evaluation: Figure 1 Display of the prepared gallate scintillator long afterglow luminescent material CaGa2O4: x%Tb 3+ The samples (x=0, 0.3, 0.6, 0.9, 1.2, 1.5) are all pure phases, which is consistent with the standard card PDF#01-073-6109, indicating that doping a small amount of Tb does not change the crystal phase.

[0026] Figure 2 It is shown that under 242nm wavelength excitation, the luminescence wavelength of the prepared gallate scintillator long afterglow luminescent material is multiple Tb in the range of 400nm-700nm. 3+ The characteristic emission of Tb is located at 543nm. 3+ The optimal doping concentration is x=1.2%.

[0027] Figure 3 The results show that the luminescent material can continuously emit a luminous brightness of 0.32 mcd / m for more than 3 hours, which is discernible to the human eye. 2 above visible light.

[0028] Figure 4 This is the thermoelectric spectrum of the gallate scintillator long afterglow luminescent material obtained in Example 1. The higher the thermoelectric peak intensity and the higher the peak temperature within a certain range, the more conducive it is to improving the afterglow performance at room temperature. 3+ There are three thermal release peaks, located at T = 342K, 385K, and 446K respectively. According to the formula E(eV) = T m (K) / 500 can be used to calculate the trap depth. The trap depths of the long afterglow luminescent materials are E=0.684eV, E=0.770eV, and E=0.892eV, respectively. The trap depth of 0.6eV to 0.8eV is most favorable for the generation of long afterglow at room temperature. Figure 4 It also shows that CaGa2O4: 1.2%Tb 3+ The thermal release peak intensity is higher, indicating that the trap concentration is greater, which is more conducive to the extension of the afterglow time; overall, it shows that adjusting Tb 3+ The doping concentration of CaGa2O4: 1.2% Tb is beneficial to improve the afterglow performance of the luminescent material. 3+ The long afterglow luminescent material has the best performance.

[0029] Example 2 According to the molecular formula CaGa2O4: 1.2%Tb 3+ , y%Li +According to the stoichiometric ratio shown in (y=0, 1, 2, 3, 5, 7), 300.27 mg of CaCO3, 562.32 mg of Ga2O3, 12.418 mg of Tb(NO3)3, and 1.108-7.758 mg of Li2CO3 were weighed respectively, and the weighed raw materials were placed in an agate mortar, and anhydrous ethanol was added and ground until mixed uniformly to obtain a precursor powder. The precursor powder was transferred to a corundum crucible, placed in a muffle furnace, and calcined at a temperature of 1100-1300°C in an air atmosphere at a heating rate of 5°C / min for 3-6 hours. The product was naturally cooled to room temperature to obtain a calcined product, and the calcined product obtained by grinding was prepared as a gallate scintillator long afterglow luminescent material.

[0030] Product structure characterization and performance evaluation: Figure 5 The gallate scintillator long afterglow luminescent material CaGa2O4: 1.2%Tb 3+ , y%Li + The XRD patterns of the samples (y=0, 1, 2, 3, 5, 7) are pure phases, which are consistent with the standard card PDF#01-073-6109, indicating that doping with a small amount of Li does not produce impurity phases.

[0031] Figure 6 The results show that under the excitation of 242nm wavelength, the luminescence wavelength range of the prepared gallate scintillator long afterglow luminescent material is between 400nm and 700nm, and the emission peak is around 543nm, which belongs to Tb 3+ The 5D4-7F5 characteristic transition, in which Li + Acting as a charge compensator, Li + The lattice distortion caused by doping will change the Tb 3+ The local crystal field symmetry around is conducive to the secondary enhancement of luminescence. The inset shows that as the value y increases, the emission intensity first increases and then decreases. The optimal doping concentration is when y=2%.

[0032] Figure 7 The results show that the luminescent material can continuously emit luminous brightness of 0.32 mcd / m for more than 7 hours, which is discernible by human eyes. 2 above visible light.

[0033] Figure 8 This is the thermoluminescent spectrum of the gallate scintillator long afterglow luminescent material obtained in Example 2. The higher the thermoluminescent peak intensity and the higher the peak temperature within a certain range, the more conducive it is to improving the afterglow performance at room temperature. 3+ , 2% Li + There are four thermal release peaks, located at T = 338K, 398K, 450K, and 480K. According to the formula E(eV) = T m(K) / 500 can be used to calculate the trap depth. The trap depths of the long afterglow luminescent materials are E=0.676eV, E=0.796eV, E=0.900eV, and E=0.960eV, respectively. The trap depth of 0.6eV to 0.8eV is most favorable for the generation of long afterglow at room temperature. Figure 8 It also shows that CaGa2O4: 1.2%Tb 3+ , 2% Li + The thermal release peak intensity is higher, indicating that the trap concentration is greater, which is more conducive to the extension of the afterglow time; Figure 8 General description Adjustment + The doping concentration of CaGa2O4: 1.2%Tb is beneficial to improve the afterglow performance of the luminescent material. 3+ , 2% Li + The long afterglow luminescent material has the best performance.

[0034] Fig. 9 When the display material is excited by X-rays, it produces a long bright green afterglow visible to the naked eye. The emission peak is located at 548nm and has a strong afterglow intensity.

[0035] Fig.10 The afterglow time of the material after being excited by X-rays is more than 1 hour.

[0036] Fig.11 After the display material was excited by 254nm ultraviolet light and X-rays (excitation time was 5 minutes), a photo was taken with a mobile phone 1 minute later, showing that a bright green afterglow was produced.

[0037] Fig.12 The low-temperature thermoluminescence spectrum of the material after X-ray excitation is significantly different from that after UV light excitation, indicating that after X-ray excitation, multiple new defect types different from the inherent defect structure are generated in the material.

Claims

1. A gallate scintillator long afterglow luminescent material excited by X-rays and UV ultraviolet light, characterized in that: The chemical formula of the luminescent material is CaGa2O4: x%Tb 3+ , y%Li + ; 0.3≤x≤1.5, 0≤y≤7; the emission wavelength is 400~700nm.

2. The X-ray and UV ultraviolet light excited gallate scintillator long afterglow luminescent material as claimed in claim 1, characterized in that: The chemical formula of the luminescent material is CaGa2O4: x%Tb 3+ ; The values ​​of x are 0.3, 0.6, 0.9, 1.2, and 1.

5.

3. The X-ray and UV ultraviolet light excited gallate scintillator long afterglow luminescent material as claimed in claim 1, characterized in that: The chemical formula of the luminescent material is CaGa2O4: 1.2%Tb 3+ , y%Li + ; The values ​​of y are 1, 2, 3, 5, 7.

4. A method for preparing the X-ray and UV ultraviolet light excited gallate scintillator long afterglow luminescent material as claimed in claim 1, characterized in that: The following steps are involved: 1) According to the chemical formula CaGa2O4: x%Tb 3+ , y%Li + According to the stoichiometric ratio of each element in the formula, Ga2O3, CaCO3, Tb(NO3)3 or Tb4O7 and Li2CO3 are weighed as raw materials respectively; 2) Place the weighed raw materials in an agate mortar, add anhydrous ethanol, grind for 1-2 hours and mix well to obtain a precursor powder; 3) Place the precursor powder in a corundum crucible, put it in a Muffle furnace, heat it to 1100~1300℃ at a heating rate of 5℃ / min in an air atmosphere, calcine it for 3~6h, cool it naturally to room temperature, obtain the calcined product, grind it, and prepare the gallate scintillator long afterglow luminescent material.

5. The method for preparing a gallate scintillator long afterglow luminescent material excited by X-rays and UV light as claimed in claim 4, characterized in that: The amount of anhydrous ethanol added is 400% to 600% of the total weight of the raw material mixture.

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