A phosphatic structure silicate fluorescent powder, a preparation method thereof and application thereof in the field of optical temperature sensing

Abstract

The application provides an apatite structure silicate fluorescent powder, a preparation method thereof and application thereof in the field of optical temperature sensing, and relates to the technical field of fluorescent materials. z (SiO4)6O2:0.01Bi 3+ ,xEu 3+ ; 0 < x < 0.12, z = 8(1-0.01-x). The application adjusts Bi 3+ →Eu 3+ energy transfer by controlling Eu 3+ doping concentration in the Mg2Gd8(SiO4)6O2 matrix, realizes tuning of the fluorescent powder from blue light to red light, and particularly, the Bi 3+ →Eu 3+ energy transfer in the process of temperature rise and drop is beneficial to improving the temperature measurement sensitivity of the fluorescent temperature probe based on FIR, and realizes high-sensitivity optical temperature sensing (the maximum relative sensitivity reaches 0.92%K ‑1 (498K)). Meanwhile, the fluorescent powder can also be widely applied in the field of temperature visualization.

Description

Technical Field

[0001] This invention relates to the field of fluorescent materials technology, and in particular to an apatite-structured silicate phosphor, its preparation method, and its application in the field of optical temperature sensing. Background Technology

[0002] Currently, environmental protection and energy conservation and emission reduction are global challenges. Statistics show that lighting accounts for approximately 20% of global electricity consumption, with most of this energy failing to convert into light energy and instead being released as heat and other forms of energy. Activator ion-doped photoluminescent phosphors are widely used in solid-state lighting due to their advantages such as good stability, high luminous efficiency, energy saving, and environmental friendliness. As research into phosphors deepens, it has been discovered that their applications are no longer limited to solid-state lighting; multifunctional applications are being developed in other fields, one of which is optical temperature measurement.

[0003] Traditional contact thermometers have many limitations in use, such as being unable to measure moving objects, objects in corrosive environments, or small objects. In contrast, non-contact optical thermometers, without requiring direct contact with the object being measured, offer advantages such as a wide measurement range, fast response, and high resolution, meeting the requirements for rapid and accurate measurement. The principle of optical thermometers is primarily based on temperature-related optical parameters, such as the fluorescence intensity ratio (FIR), spectral shift, luminescence lifetime, emission bandwidth, and luminescence intensity, as a function of temperature.

[0004] Apatite crystals have the general chemical formula (A1)2(A2)3(XO4)3Y, where A1 and A2 represent divalent alkaline earth metal ions Ca. 2+ 、Sr 2+ Ba 2+ Etc., Y is mainly F - Cl - OH - XO4 represents PO4 3- SiO4 4- VO4 3- In recent years, apatite-structured phosphors have been frequently reported. Apatite, as an important phosphor matrix material, endows apatite-structured phosphors with high efficiency, thermal stability, and chemical stability. Among them, most rare-earth apatite-structured phosphors possess the high symmetry space group P63 / m. As cations in the crystal are replaced by other ions, the apatite structure crystal changes from the high symmetry space group P63 / m to the relatively low symmetry space groups P6, P63, P3, and P21 / m. In recent years, researchers have also focused on main group metal ions (Bi... 3+Pb 2+ Sn 4+ ) and transition metal ions (Cr 3+ Co 3+ Mn 2+ Mn 4+ Bismuth ions are among the non-rare earth ions. Compared with precious and scarce rare earth resources, bismuth ions have many advantages, such as large mineral reserves and relatively simple purification processes, and they have good prospects in many fields such as luminescence.

[0005] Trivalent bismuth ion (Bi 3+ ) and narrowband characteristic emission of trivalent rare earth ions (Re 3+ Due to their completely different electronic structures and temperature responses, Bi6O2 with a 6s2 configuration is considered an optimal combination for optical thermometry. 3+ Ions with Ce 3+ Eu 3 + Similarly, it exhibits broadband emission, and its luminescence performance is easily affected by surrounding environmental factors. Under certain excitation conditions, it displays multiple emission bands, covering the range from ultraviolet to red light. Re, with its 4fn electron configuration... 3+ The emission spectra of these ions are all characterized by narrow-band emission, with peak shape and position not easily affected by the crystal field environment, and they also have long luminescence lifetimes. This combination is considered a strong candidate material for applications such as optical thermometers and optical anti-counterfeiting. Related technologies reported include CaNb2O6:Bi. 3+ / Ln 3+ (Ln=Eu / Sm / Dy / Tb) series phosphors, Ca3Sc2Si3O 12 :Bi 3+ / Tb 3+ / Eu 3+ Phosphor, LaScO3:Bi 3+ / Tb 3+ / Eu 3+ Phosphors, etc., although these reported phosphors all have temperature-measuring properties, generally suffer from poor temperature sensitivity. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide an apatite-structured silicate phosphor, its preparation method, and its application in the field of optical temperature sensing. The apatite-structured silicate phosphor provided by this invention exhibits excellent luminescence properties and temperature sensitivity.

[0007] This invention provides an apatite-structured silicate phosphor with the chemical formula: Mg2Gd z (SiO4)6O2:0.01Bi 3 + ,xEu3+ ; of which 0 <x≤0.12,z=8(1-0.01-x)。

[0008] Preferably, x is 0.0025, 0.005, 0.01, 0.02, 0.04, 0.08 or 0.12.

[0009] This invention provides a method for preparing the apatite-structured silicate phosphor described in the above technical solution, comprising the following steps:

[0010] According to the stoichiometric ratio shown in the chemical formula of the apatite-structured silicate phosphor, magnesium source, gadolinium source, silicon source, bismuth source and europium source are mixed to obtain a mixture;

[0011] The mixture was calcined in air and then ground to obtain the apatite-structured silicate phosphor.

[0012] Preferably, the magnesium source includes one or more of magnesium oxide, magnesium nitrate, magnesium hydroxide, and magnesium carbonate; the gadolinium source includes one or more of gadolinium oxide, gadolinium nitrate, and gadolinium fluoride; the silicon source includes silicon dioxide; the bismuth source includes one or more of bismuth oxide, bismuth nitrate, bismuth hydroxide, and bismuth carbonate; and the europium source includes one or more of europium oxide, europium nitrate, europium hydroxide, and europium carbonate.

[0013] Preferably, the mixing method is grinding.

[0014] Preferably, the grinding process involves adding a grinding medium, which is ethanol.

[0015] Preferably, the calcination temperature is 1300–1500°C and the time is 4–6 hours.

[0016] Preferably, the calcination temperature is 1450℃ and the time is 5 hours.

[0017] This invention provides the application of the apatite-structured silicate phosphor described in the above technical solutions or the apatite-structured silicate phosphor prepared by the above technical solutions in the fields of solid-state lighting, optical temperature sensing and temperature visualization.

[0018] Preferably, the optical temperature sensor includes a non-contact optical temperature measurement device.

[0019] This invention provides an apatite-structured silicate phosphor with the chemical formula: Mg2Gd z (SiO4)6O2:0.01Bi 3 + ,xEu 3+; where 0 < x ≤ 0.12 and z = 8(1 - 0.01 - x). The present invention provides a bismuth and europium co-doped activated silicate phosphor with Mg2Gd8(SiO4)6O2 (abbreviated as MGSO) as the original matrix material. The present invention uses a specific matrix material to dope Eu 3+ into MGSO:Bi 3+ and studies the energy transfer mechanism of Bi 3+ ,Eu 3+ in MGS:Bi 3+ →Eu 3+ . By controlling the doping concentration of Eu 3+ , the tuning of the phosphor from blue light to red light is achieved; moreover, the emission spectrum of MGSO:Bi 3+ is more sensitive to temperature changes, and the narrow-band emission of Eu 3 + is less sensitive to temperature changes. Based on the fluorescence intensity ratio (FIR) of MGSO:Bi 3+ and Eu 3+ changing with temperature, high sensitivity of the phosphor to temperature can be achieved. According to the FIR of MGS:Bi 3+ ,Eu 3+ changing with temperature, the phosphor is applied to non-contact optical temperature measurement. The phosphor provided by the present invention can be effectively excited by ultraviolet light and near-ultraviolet light within the range of 250 - 450 nm, has a wide absorption range, high emission intensity, excellent color stability, and is a light conversion material with good luminescence characteristics and stability; and has excellent temperature sensitivity and FIR recovery during the heating and cooling process.

[0020] The results of the examples show that for the apatite-structured silicate phosphor provided by the present invention, as the co-doping concentration of Eu 3+ increases, its emission color can transition from the blue light region to the red light region, thereby achieving spectral regulation of the phosphor; the variable-temperature spectrum shows that the broadband emission peak of Bi 3+ is more sensitive to temperature changes than the narrow-band emission peak of Eu 3+ . Based on this feature, a temperature-sensitive response relationship of the fluorescence intensity ratio of MGSO:0.01Bi 3+ !,0.01Eu 3+ phosphor at different temperatures is established, and the relative sensitivity (S r ) is calculated. The maximum relative sensitivity S r = 0.92%K -1 , which is higher than the results of temperature-sensitive phosphors reported in relevant literature.

[0021] The present invention provides a preparation method for the apatite-structured silicate phosphor described in the above technical solutions. The raw materials are rich in source, low in price, the preparation process is simple, and the equipment requirements and production costs are low.

[0022] This invention provides the application of the apatite-structured silicate phosphor described in the above technical solutions, or the apatite-structured silicate phosphor prepared by the above preparation methods, in optical temperature sensors. The apatite-structured silicate phosphor provided by this invention can be excited by ultraviolet to blue light in the range of 250–450 nm, emitting a blue-tuned to red spectrum in the wavelength range of 350–750 nm, with the main emission peaks located in the blue region at 446 nm and the orange region at 613 nm. It exhibits good wavelength matching with near-ultraviolet LED chips (355–365 nm, 380–410 nm) and blue LED chips (445–455 nm), and can be applied in the field of white LEDs. The phosphor also possesses excellent temperature sensitivity and can be applied in temperature sensing fields, such as non-contact optical temperature measurement and visualization. The phosphor provided by this invention has promising application prospects. Attached Figure Description

[0023] Figure 1 These are luminescence photographs of the phosphors obtained in Examples 2-7 under a 365nm UV lamp. Figure 1 The phosphors in the middle, from left to right, correspond to Examples 2, 3, 4, 5, 6, and 7, respectively.

[0024] Figure 2 These are luminescence photographs of the phosphors obtained in Examples 8-14 under a 365nm UV lamp. Figure 2 From left to right, the phosphors in the middle correspond to Examples 8, 9, 10, 11, 12, 13, and 14.

[0025] Figure 3 The PL spectra of the phosphors obtained in Examples 8-14 under 315 nm excitation are shown.

[0026] Figure 4 MGSO: 1mol%Bi 3+ ,ymol%Eu 3+ (y = 0.25 ~ 12.00) CIE chromaticity coordinates of the sample. Figure 4 (a) is the CIE chromaticity coordinate diagram, and (b) is the chromaticity coordinate value of the phosphor at room temperature when y = 0.25 to 12.00;

[0027] Figure 5 In the example, MGSO: 1 mol% Bi 3+ MGSO: 1mol%Bi 3+ 1 mol% Eu 3+ And the XRD diffraction pattern of MGSO;

[0028] Figure 6In the example, MGSO: 1 mol% Bi 3+ 1 mol% Eu 3+ Rietveld refined XRD pattern of phosphor;

[0029] Figure 7 MGSO:1mol%Bi prepared in Example 10 3+ 1 mol% Eu 3+ SEM images and elemental mapping distribution (EDS) images of phosphors;

[0030] Figure 8 This is a schematic diagram of the crystal structure of MGSO;

[0031] Figure 9 In the example, MGSO: 1 mol% Bi 3+ 1 mol% Eu 3+ Temperature-dependent PL spectra;

[0032] Figure 10 for Bi 3+ and Eu 3+ The trend of integral intensity as a function of temperature;

[0033] Figure 11 The temperature-dependent FIR fitting curve;

[0034] Figure 12 MGSO: 1mol%Bi 3+ 1 mol% Eu 3+ The variation of Sa and Sr values ​​of phosphors with temperature;

[0035] Figure 13 MGSO: 1mol%Bi 3+ 1 mol% Eu 3+ FIR reactivity of phosphors during heating and cooling processes;

[0036] Figure 14 MGSO: 1mol%Bi 3+ 1 mol% Eu 3+ CIE chromaticity coordinates of phosphor in the temperature range of 298–498 K Figure 14 (a) is the CIE chromaticity coordinate diagram, and (b) is the MGSO:1mol%Bi diagram. 3+ 1 mol% Eu 3+ Chromaticity coordinates of phosphor in the temperature range of 298–498 K. Detailed Implementation

[0037] This invention provides an apatite-structured silicate phosphor with the chemical formula: Mg2Gd z(SiO4)6O2:0.01Bi 3 + ,xEu 3+ ; of which 0 <x≤0.12,z=8(1-0.01-x)。

[0038] The phosphor provided by this invention uses Mg2Gd8(SiO4)6O2 (abbreviated as MGSO) as the original host matrix and Bi as the base. 3+ and Eu 3+ It is a dopant ion. In this invention, 0.01 in the chemical formula represents Bi. 3+ The molar ratio of Gd doping in the original host matrix Mg2Gd8(SiO4)6O2, where x represents Eu 3+ The molar ratio of Gd doping in the original host matrix Mg2Gd8(SiO4)6O2, and the Gd sites in the original host matrix after being treated with a certain proportion of Bi 3+ and Eu 3+ Doping and substitution to form Mg2Gd z (SiO4)6O2, wherein z = 8(1-0.01-x), and x is preferably 0.0025, 0.005, 0.01, 0.02, 0.04, 0.08 or 0.12.

[0039] In this embodiment of the invention, the phosphor is also represented as MGSO:1mol%Bi 3+ ,ymol%Eu 3+ The form is y = 100x.

[0040] The apatite-structured silicate phosphor provided by this invention uses Mg₂Gd₈(SiO₄)₆O₂ (abbreviated as MGSO) as the matrix material, with bismuth and europium as co-doped activating ions. Mg₂Gd₈(SiO₄)₆O₂ contains two low-symmetry cation sites: a C₃-symmetric 9-coordinate 4f site and a Cs-symmetric 7-coordinate 6h site. Mg and Gd atoms are distributed at these two sites in a certain ratio. Activating ions can replace Mg or Gd sites to occupy both sites (in this invention, activating ions tend to occupy Gd sites). Due to the presence of Mg, the MGSO matrix exhibits higher temperature resistance and a more stable crystal structure compared to other apatite structures. Mg and Gd are located at the A position in the general formula and can be replaced by rare earth ions to form luminescent centers. [SiO₄] 4-The silicon (Si) is an anionic group, forming a stable framework of silicon-oxygen tetrahedra, in which Si cannot be replaced by rare-earth ions. The final O is an adduct anion, also known as a channel anion. Apatite-structured silicates contain two types of cationic lattice sites with local symmetries of C3 and Cs, corresponding to the 9-coordinated 4f site and the 7-coordinated 6h site, respectively. Both sites can accommodate various activator ions, becoming the luminescent centers of phosphors.

[0041] This invention is the first to combine a Mg2Gd8(SiO4)6O2 matrix with Bi 3+ Eu 3+ Co-doping yields apatite-structured silicate phosphors that can be effectively excited by ultraviolet and near-ultraviolet light, exhibiting a wide absorption range, high emission intensity, and excellent optical properties and temperature sensitivity. In this invention, the apatite-structured silicate phosphor contains Bi... 3+ To Eu 3+ Energy transfer, when the phosphor is excited at 315 nm, Bi 3+ To Eu 3+ The energy transfer efficiency between them can reach up to 51.74%. The apatite-structured silicate phosphor provided by this invention, along with Eu... 3+ Increasing the co-doping concentration allows the emission color to transition from the blue to the red region, thus enabling spectral modulation of the phosphor. Furthermore, MGSO:Bi 3+ The emission spectrum of Eu is quite sensitive to temperature changes. 3+ The narrowband emission is insensitive to temperature changes, based on MGSO:Bi 3+ With Eu 3+ The fluorescence intensity ratio (FIR) that varies with temperature enables phosphors to achieve high temperature sensitivity.

[0042] This invention provides a method for preparing the apatite-structured silicate phosphor described in the above technical solution, comprising the following steps:

[0043] According to the stoichiometric ratio shown in the chemical formula of the apatite-structured silicate phosphor, magnesium source, gadolinium source, silicon source, bismuth source and europium source are mixed to obtain a mixture;

[0044] The mixture was calcined in air and then ground to obtain the apatite-structured silicate phosphor.

[0045] Unless otherwise specified, all raw materials involved in this invention are commercially available products well known in the art.

[0046] According to the chemical formula of the apatite-structured silicate phosphor, the present invention mixes magnesium source, gadolinium source, silicon source, bismuth source and europium source in the stoichiometric ratio shown to obtain a mixture.

[0047] In this invention, the magnesium source preferably includes one or more of magnesium oxide (MgO), magnesium nitrate (Mg(NO3)2·6H2O), magnesium hydroxide (Mg(OH)2), and magnesium carbonate (MgCO3); the gadolinium source preferably includes one or more of gadolinium oxide (Gd2O3), gadolinium nitrate, and gadolinium fluoride; the silicon source preferably includes silicon dioxide (SiO2); the bismuth source preferably includes one or more of bismuth oxide (Bi2O3), bismuth nitrate (Bi(NO3)3·6H2O), bismuth hydroxide (Bi(OH)3), and bismuth carbonate (Bi2(CO3)3); and the europium source preferably includes one or more of europium oxide (Eu2O3), europium nitrate (Eu(NO3)3·6H2O), europium hydroxide (Eu(OH)3), and europium carbonate (Eu2(CO3)3). In this invention, the magnesium source, silicon source and gadolinium source are preferably of analytical grade, and the bismuth source and europium source are preferably of 99.99% purity.

[0048] In this invention, the mixing method is preferably grinding, and the grinding preferably involves adding a grinding medium, preferably ethanol. The volume ratio of the ethanol to the total volume of the magnesium source, gadolinium source, silicon source, bismuth source, and europium source is preferably 1:1. Preferably, the magnesium source, gadolinium source, silicon source, bismuth source, and europium source are placed in an agate mortar, the grinding medium is added, and grinding is performed. This invention does not have specific requirements for the grinding time, as long as the raw materials are mixed evenly. After grinding, it is preferable to completely evaporate the grinding medium.

[0049] After obtaining the mixture, the present invention calcines the mixture in an air atmosphere and then grinds it to obtain the apatite-structured silicate phosphor.

[0050] In this invention, the calcination temperature is preferably 1300–1500℃, specifically 1300℃, 1350℃, 1380℃, 1400℃, 1430℃, 1450℃, or 1470℃, more preferably 1450℃, and the calcination time is preferably 4–6 hours, more preferably 5 hours. Preferably, the mixture is transferred to a corundum crucible and placed in a high-temperature tube furnace for calcination. During the calcination process, the raw materials undergo diffusion, reaction, nucleation, and growth processes to ultimately obtain an inorganic crystalline material.

[0051] After calcination, the present invention preferably cools the obtained calcined material (block sample) naturally to room temperature in a high-temperature tube furnace under an air atmosphere.

[0052] In this invention, the grinding is preferably carried out in an agate mortar; this invention does not have special requirements for the particle size of the grinding, as long as it presents as a uniform powder.

[0053] This invention synthesizes the apatite-structured silicate phosphor via a high-temperature solid-state method. The raw materials are readily available, the process is simple, the preparation cost is low, and it can be mass-produced. Compared with sulfides, halides, and nitrides, it is energy-efficient, green, and environmentally friendly.

[0054] This invention provides the application of the apatite-structured silicate phosphor described in the above technical solutions or the apatite-structured silicate phosphor prepared by the above technical solutions in the fields of solid-state lighting, optical temperature sensing and temperature visualization.

[0055] The apatite-structured silicate phosphor provided by this invention has the advantages of broadband absorption and narrowband emission in the ultraviolet to visible light range. It can be used to manufacture the orange-red component of ultraviolet-excited white LEDs and combined with ultraviolet LED chips to prepare high-performance white LEDs.

[0056] In this invention, the optical temperature sensing preferably includes a non-contact optical temperature measurement device. The phosphor provided by this invention is a phosphor based on the broadband-to-narrowband fluorescence intensity ratio in a binary co-doped system with a single matrix. Its temperature measurement is based on the fluorescence intensity ratio of dual emission peaks. This method is less dependent on measurement conditions, not limited by fluctuations in the excitation source intensity, or by changes in luminescence intensity caused by non-temperature factors such as the number and distribution of luminescent centers, resulting in small measurement errors. This measurement method utilizes the different changes in fluorescence intensity emitted by two adjacent thermally coupled energy levels or two different luminescent centers, using their intensity ratio to reflect temperature. The phosphor provided by this invention has promising application prospects in the field of non-contact optical temperature measurement.

[0057] To further illustrate the present invention, the following detailed description, in conjunction with examples, illustrates the apatite-structured silicate phosphor, its preparation method, and its application in the field of fluorescence temperature sensing. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0058] Example 1: Mg2Gd8(SiO4)6O2 phosphor

[0059] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), and 1.450 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add ethanol of the same volume as the raw materials, and grind for 30 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1350°C for 5 hours in air atmosphere. Allow it to cool naturally to room temperature in air atmosphere within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits blue light under a 365 nm ultraviolet lamp.

[0060] Example 2: Mg2Gd 8(1-0.005)(SiO4)6O2:0.005Bi 3+ fluorescent powder

[0061] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0093 g of Bi2O3 (99.99%), and 1.4428 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 30 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1350°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits blue light under a 365 nm ultraviolet lamp.

[0062] Example 3: Mg2Gd 8(1-0.01) (SiO4)6O2:0.01Bi 3+ fluorescent powder

[0063] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0186 g of Bi2O3 (99.99%), and 1.4355 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 30 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1350°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits blue light under a 365 nm ultraviolet lamp.

[0064] Example 4: Mg2Gd 8(1-0.02) (SiO4)6O2:0.02Bi 3+ fluorescent powder

[0065] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0373 g of Bi2O3 (99.99%), and 1.421 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 30 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1350°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits blue light under a 365 nm ultraviolet lamp.

[0066] Example 5: Mg2Gd 8(1-0.03) (SiO4)6O2:0.03Bi 3+ fluorescent powder

[0067] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0559 g of Bi2O3 (99.99%), and 1.4065 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 30 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1350°C for 5 hours in air. Cool to room temperature in air within the high-temperature tube furnace, and grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits blue light under a 365 nm ultraviolet lamp.

[0068] Example 6: Mg2Gd 8(1-0.04) (SiO4)6O2:0.04Bi 3+ fluorescent powder

[0069] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0745 g of Bi2O3 (99.99%), and 1.392 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 30 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1350°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits blue light under a 365 nm ultraviolet lamp.

[0070] Example 7: Mg2Gd 8(1-0.05) (SiO4)6O2:0.05Bi 3+ fluorescent powder

[0071] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0932 g of Bi2O3 (99.99%), and 1.3775 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 30 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1350°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits blue light under a 365 nm ultraviolet lamp.

[0072] Figure 1 These are luminescence photographs of the phosphors obtained in Examples 2-7 under a 365nm UV lamp. Figure 1 From left to right, the following correspond to Example 2 (Mg2Gd) 8(1-0.005) (SiO4)6O2:0.005Bi 3+ Example 3 (Mg2Gd) 8(1-0.01) (SiO4)6O2:0.01Bi 3 + Example 4 (Mg2Gd) 8(1-0.02) (SiO4)6O2:0.02Bi 3+ Example 5 (Mg2Gd) 8(1-0.03) (SiO4)6O2:0.03Bi 3+ Example 6 (Mg) 2(1-0.04) Gd8(SiO4)6O2:0.04Bi 3+ Example 7 (Mg2Gd) 8(1-0.05) (SiO4)6O2:0.05Bi 3+ The phosphor contains 0.01 Bi 3+ This is the optimal doping concentration, at which the phosphor exhibits the highest luminescence intensity.

[0073] Example 8: Mg2Gd 8(1-0.01-0.0025) (SiO4)6O2:0.01Bi 3+ 0.0025Eu 3+ fluorescent powder

[0074] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0186 g of Bi2O3 (99.99%), 0.0035 g of Eu2O3 (99.99%), and 1.4319 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 40 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1450°C for 5 hours in air. Cool to room temperature in air within the high-temperature tube furnace, and grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits blue light under a 365 nm ultraviolet lamp.

[0075] Example 9: Mg2Gd 8(1-0.01-0.005) (SiO4)6O2:0.01Bi 3+ 0.005Eu 3+ fluorescent powder

[0076] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0186 g of Bi2O3 (99.99%), 0.0070 g of Eu2O3 (99.99%), and 1.4283 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 40 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1450°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting blocky sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits a bluish fluorescence under a 365 nm ultraviolet lamp.

[0077] Example 10: Mg2Gd 8(1-0.01-0.01) (SiO4)6O2:0.01Bi 3+ 0.01Eu 3+ fluorescent powder

[0078] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0186 g of Bi2O3 (99.99%), 0.0141 g of Eu2O3 (99.99%), and 1.421 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 40 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1450°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits a bluish-white light under a 365 nm ultraviolet lamp.

[0079] Example 11: Mg2Gd 8(1-0.01-0.02) (SiO4)6O2:0.01Bi 3+ 0.02Eu 3+ fluorescent powder

[0080] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0186 g of Bi2O3 (99.99%), 0.0281 g of Eu2O3 (99.99%), and 1.4065 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 40 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1450°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits a yellow-orange light under a 365 nm ultraviolet lamp.

[0081] Example 12: Mg2Gd 8(1-0.01-0.04) (SiO4)6O2:0.01Bi 3+ 0.04Eu 3+ fluorescent powder

[0082] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0186 g of Bi2O3 (99.99%), 0.0563 g of Eu2O3 (99.99%), and 1.3775 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 40 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1450°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits a yellow-orange light under a 365 nm ultraviolet lamp.

[0083] Example 13: Mg2Gd 8(1-0.01-0.08) (SiO4)6O2:0.01Bi 3+ 0.08Eu 3+ fluorescent powder

[0084] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0186 g of Bi2O3 (99.99%), 0.1126 g of Eu2O3 (99.99%), and 1.3195 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 40 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1450°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits orange light under a 365 nm ultraviolet lamp.

[0085] Example 14: Mg2Gd 8(1-0.01-0.12) (SiO4)6O2:0.01Bi 3+ 0.12Eu 3+ fluorescent powder

[0086] Weigh out 0.0806 g of MgO (analytical grade), 0.3605 g of SiO2 (analytical grade), 0.0186 g of Bi2O3 (99.99%), 0.1689 g of Eu2O3 (99.99%), and 1.2615 g of Gd2O3 (analytical grade). Place the above raw materials in an agate mortar, add an equal volume of ethanol, and grind for 40 minutes to ensure thorough mixing. After the raw materials are evenly mixed and the ethanol has completely evaporated, transfer the mixture to a corundum crucible and place it in a high-temperature tube furnace. Calcinate at 1450°C for 5 hours in air. Allow the mixture to cool naturally to room temperature in air within the high-temperature tube furnace. Grind the resulting block sample into powder in an agate mortar to obtain the desired fluorescent powder. The sample emits orange-red light under a 365 nm ultraviolet lamp.

[0087] Figure 2 These are luminescence photographs of the phosphors obtained in Examples 8-14 under a 365nm UV lamp. Figure 2 From left to right, the corresponding examples are Example 8 (Mg2Gd) 8(1-0.01-0.0025) (SiO4)6O2:0.01Bi 3+ 0.0025Eu 3+ Example 9 (Mg2Gd) 8(1-0.01-0.005) (SiO4)6O2:0.01Bi 3+ 0.005Eu 3+ Example 10 (Mg2Gd) 8(1-0.01-0.01) (SiO4)6O2:0.01Bi 3+ 0.01Eu 3+ Example 11 (Mg2Gd) 8(1-0.01-0.02) (SiO4)6O2:0.01Bi3+ 0.02Eu 3+ Example 12 (Mg2Gd) 8(1-0.01-0.04) (SiO4)6O2:0.01Bi 3+ 0.04Eu 3+ Example 13 (Mg2Gd) 8(1-0.01-0.08) (SiO4)6O2:0.01Bi 3+ 0.08Eu 3+ Example 14 (Mg2Gd) 8(1-0.01-0.12) (SiO4)6O2:0.01Bi 3+ 0.12Eu 3+ () fluorescent powder.

[0088] Figure 3 The PL spectra of the phosphors obtained in Examples 8-14 under 315 nm excitation were obtained by different Eu... 3+ Doping concentration, finding the maximum emission intensity, and determining the optimal doping Eu 3+ The molar concentration was 0.08 Eu. 3+ This is the optimal doping concentration, at which the emission intensity is the highest.

[0089] This invention is based on Bi 3+ With Eu 3+ The energy transfer mechanism between them was investigated, resulting in a series of MGSO:Bi with tunable luminescence colors. 3+ Eu 3+ Phosphor. To more intuitively understand the effect of emission color on Eu... 3+ Concentration dependence, MGSO:1mol%Bi 3+ ,y mol%Eu 3+ The PL spectra of the samples (y = 0.25–12.00) were converted into chromaticity coordinates for observation. The color points of the samples and their corresponding photographs under a 365 nm UV lamp were plotted on a CIE chromaticity coordinate system. The results are as follows: Figure 4 As shown, Figure 4 (a) shows the CIE chromaticity coordinate diagram, with the inset showing the fluorescence of the phosphor under a 365nm UV lamp (the corresponding y values ​​from left to right are 0.25, 0.5, 1, 2, 4, 8, and 12). Figure 4 In Figure (b), the chromaticity coordinates of the phosphor at room temperature are given by y = 0.25–12. It can be clearly seen that as Eu... 3+ As the doping concentration continued to increase, the phosphor was gradually tuned from blue light to red light.

[0090] Figure 5 Mg2Gd prepared in Example 3 8(1-0.01) (SiO4)6O2:0.01Bi 3+Phosphor (MGSO: 1mol% Bi) 3+ ), Mg2Gd prepared in Example 10 8(1-0.01-0.01) (SiO4)6O2:0.01Bi 3+ 0.01Eu 3+ Phosphor (MGSO: 1mol% Bi) 3+ 1 mol% Eu 3+ XRD diffraction patterns of Mg2Gd8(SiO4)6O2 host matrix and Mg2Gd8(SiO4)6O2. The diffraction patterns obtained in Examples 3 and 10 are compared with those of Mg2Gd8(SiO4)6O2 host matrix. 4)6 The O2 ICSD card showed consistency with the sample, and no impurity peaks were detected, indicating trace Bi doping. 3+ / Eu 3+ Even after the ions entered the crystal lattice, the sample retained the pure MGSO phase. For further analysis, the diffraction patterns of the three samples were refined using Rietveld refinement. The original model used for Rietveld refinement analysis was also Mg₂Gd₈(SiO₄)₆O₂, and the results are as follows: Figure 6 As shown, the Rietveld refinement results of the diffraction pattern indicate that the crystal structure data are reliable, further demonstrating that the obtained phosphor sample remains a pure phase even with activator doping. Example 3: Mg₂Gd 8(1-0.01) (SiO4)6O2:0.01Bi 3+ Phosphor (MGSO: 1mol% Bi) 3+ ), Mg2Gd prepared in Example 10 8(1-0.01-0.01) (SiO4)6O2:0.01Bi 3+ 0.01Eu 3+ Phosphor (MGSO: 1mol% Bi) 3+ 1 mol% Eu 3+ The refinement parameters of the Mg2Gd8(SiO4)6O2 matrix (MGSO) are shown in Table 1.

[0091] Table 1 MGSO: 1 mol% Bi 3+ MGSO: 1mol%Bi 3+ 1 mol% Eu 3+ And the fine-tuning parameters of MGSO

[0092]

[0093] Crystal structure model of MGSO ( Figure 8As shown in the diagram, the MGSO crystal is composed of three polyhedra: a 9-coordinate tetrahedron, a 7-coordinate decahedron, and a 4-coordinate Si-O tetrahedron. However, since the Si-O tetrahedron cannot be substituted by activator ions, it will not be discussed further. The central atom of the tetrahedron and decahedron is Mg. 2+ or Gd 3+ Atoms, both distributed in a certain proportion, can accommodate activator ions; the tetrahedron consists of one cation (Mg). 2+ or Gd 3+ The decahedron consists of a cation (Mg) and nine surrounding oxygen atoms, with the cation located at the 4f site and exhibiting C3 symmetry; the decahedron is composed of a single cation (Mg). 2+ or Gd 3+ The cation is composed of 7 oxygen atoms and is located at the 6h site, exhibiting Cs symmetry. Rietveld refinement results show that Bi... 3+ and Eu 3 + They tend to occupy Gd sites to form luminescent centers.

[0094] Mg2Gd prepared in Example 10 8(1-0.01-0.01) (SiO4)6O2:0.01Bi 3+ 0.01Eu 3+ Phosphor (MGSO: 1mol% Bi) 3+ 1 mol% Eu 3+ Characterization was performed using SEM and EDS, and the results are as follows: Figure 7 As shown. Through MGSO:Bi 3+ Eu 3+ SEM images of the samples revealed the microstructure of the phosphor, and EDS elemental mapping was used to analyze the uniformity of elemental distribution. The results showed that Mg, Gd, Si, O, Bi, and Eu elements were uniformly distributed in the matrix, confirming that the reactants were the desired substances.

[0095] The emission spectrum has been measured and shows that Bi 3+ and Eu 3+ The emission bands are independent of each other, meaning that the prepared MGSO:Bi can be utilized. 3+ Eu 3+ Phosphors were used to test the temperature dependence of the emission spectrum, thereby designing an optical temperature sensor. To explore the potential applications of the prepared sample in optical thermometry, the temperature dependence of MGSO:1mol%Bi was tested. 3+ 1 mol% Eu 3+ PL spectra of the sample at different temperatures. MGSO:1mol%Bi in the range of 298–498 K. 3+ 1 mol% Eu 3+Temperature-dependent PL spectra (i.e., variable-temperature spectra) such as Figure 9 As shown ( Figure 9 The characteristic peaks of Bi are visible in the lower 350–525 nm range. During the heating process, the intensity changes of the overall PL spectrum of the sample exhibit a similar trend, i.e., Bi... 3+ and Eu 3+ The corresponding PL spectral intensity gradually decreases with increasing temperature, a common phenomenon caused by thermal quenching. However, from... Figure 10 The integral intensity histogram shows that in MGSO:1mol%Bi 3+ 1 mol% Eu 3+ Medium, Bi 3+ The fluorescence intensity of Eu showed a significant decreasing trend, indicating that... 3+ To Bi 3+ The FIR value of ions is strongly dependent on temperature. Figure 11 The temperature-dependent FIR fitting curve shows that different data values ​​can be used to measure different temperatures.

[0096] Based on the above characteristics, the absolute sensitivity (S) was calculated. a ) and relative sensitivity (S r ), Figure 12 MGSO: 1mol%Bi 3 + 1 mol% Eu 3+ The variation of Sa and Sr values ​​of the phosphor with temperature shows that the maximum absolute sensitivity S a =0.0047K -1 Maximum relative sensitivity S r =0.92%K -1 (498K). The prepared MGSO:1 mol% Bi 3+ 1 mol% Eu 3+ The Sa and Sr values ​​of the phosphor and some recently published thermosensitive phosphors were compared (as shown in Table 2, where Mg2Gd8(SiO4)6O2:Bi) 3+ Eu 3+ The present invention is MGSO:1mol%Bi 3+ 1 mol% Eu 3+ Phosphor, SrY2O4:Bi 3+ Eu 3+ and SrLu2O4:Bi 3+ Eu 3+ (This is a recently reported phosphor), MGSO: 1mol% Bi 3+ 1 mol% Eu 3+The Sr value of the phosphor is higher than that reported in the literature. Within the K range of 298–498 K, MGSO:1 mol% Bi 3+ 1 mol% Eu 3+ The PL spectral chromaticity coordinates of the phosphor sample are as follows: Figure 14 As shown, the color changes with temperature in a regular trend. 。 In addition, such as Figure 13 As shown, the FIR curves of the sample were almost completely reversible during the heating (298→498K) and cooling (498→298K) processes. These results indicate that the prepared MGSO:1mol%Bi 3+ 1 mol% Eu 3+ Phosphors possess excellent temperature sensitivity and FIR reversion during heating and cooling processes, demonstrating their potential application value in the field of temperature sensing.

[0097] Table 2 Comparison of optical parameters of temperature-sensitive phosphors

[0098]

[0099]

[0100] Example 15

[0101] MGSO:0.01Bi at different preparation temperatures 3+ 0.01Eu 3+ Research on phosphors

[0102] The calcination temperatures in Example 10 were changed to 1250℃, 1300℃, 1350℃, 1380℃, 1400℃, 1430℃, and 1470℃, respectively, while the rest remained the same as in Example 10.

[0103] Phosphors were obtained at a calcination temperature of 1250℃, but a pure phase sample could not be synthesized.

[0104] Phosphors were obtained by calcination at 1300℃, but a pure phase sample could not be synthesized.

[0105] Phosphors were obtained by calcination at 1350℃, and a pure phase sample was synthesized. However, the sample showed low luminescence intensity under a 365nm ultraviolet lamp.

[0106] Phosphors were obtained by calcination at 1380℃. The sample was a pure phase, but the luminescence intensity of the sample was low under a 365nm ultraviolet lamp.

[0107] Phosphors were obtained by calcination at 1400℃. The sample was a pure phase and exhibited moderate luminescence intensity under a 365nm ultraviolet lamp.

[0108] Phosphors were obtained by calcination at 1430℃. The sample was a pure phase and exhibited moderate luminescence intensity under a 365nm UV lamp.

[0109] The phosphor was obtained by calcination at 1470℃. The sample melted and showed no luminescence.

[0110] In Example 10, phosphors were obtained by calcination at 1450°C, and a pure phase was synthesized. The sample showed the best luminescence intensity under a 365nm ultraviolet lamp.

[0111] This invention synthesizes a series of MGSO:Bi using a high-temperature solid-state method. 3+ and MGSO:Bi 3+ Eu 3+ Phosphors. The morphology, structure, luminescent properties, and thermosensitivity of the prepared phosphors were systematically characterized, and the effects of MGSO:Bi on phosphors were investigated. 3+ Eu 3+ Zhongbi 3+ →Eu 3+ The energy transfer mechanism, through controlling Eu 3+ The doping concentration enables the phosphor to be tuned from blue to red light. Eu doping... 3+ Subsequently, the chromaticity coordinates and correlated color temperature (CCT) of the phosphor changed. In variable-temperature spectroscopy testing, it was found that MGSO:Bi... 3+ The emission spectrum of Eu is quite sensitive to temperature changes, considering that Eu 3+ The narrowband emission is insensitive to temperature changes, according to MGSO:Bi 3+ Eu 3+ The temperature-dependent FIR (Fluorescent Irradiance) of this phosphor allows it to be used in non-contact optical temperature measurement. The MGSO:Bi provided by this invention... 3+ Eu 3+ Phosphors have potential applications in solid-state lighting and optical temperature measurement.

[0112] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A silicate phosphor with an apatite structure, characterized in that, The chemical formula is: Mg2Gdz(SiO4)6O2:0.01Bi 3+ ,xEu 3+ Where x is 0.0025, 0.005, 0.01, 0.02, 0.04, 0.08 or 0.12, and z = 8(1-0.01-x); The preparation method of the apatite-structured silicate phosphor includes the following steps: According to the stoichiometric ratio shown in the chemical formula of the apatite-structured silicate phosphor, magnesium source, gadolinium source, silicon source, bismuth source and europium source are mixed to obtain a mixture; The mixture was calcined in air and then ground to obtain the apatite-structured silicate phosphor; the calcination temperature was 1450℃ and the time was 5h.

2. The method for preparing the apatite-structured silicate phosphor according to claim 1, characterized in that, Includes the following steps: According to the stoichiometric ratio shown in the chemical formula of the apatite-structured silicate phosphor, magnesium source, gadolinium source, silicon source, bismuth source and europium source are mixed to obtain a mixture; The mixture was calcined in air and then ground to obtain the apatite-structured silicate phosphor; the calcination temperature was 1450℃ and the time was 5h.

3. The preparation method according to claim 2, characterized in that, The magnesium source includes one or more of magnesium oxide, magnesium nitrate, magnesium hydroxide, and magnesium carbonate; the gadolinium source includes one or more of gadolinium oxide, gadolinium nitrate, and gadolinium fluoride; the silicon source includes silicon dioxide; the bismuth source includes one or more of bismuth oxide, bismuth nitrate, bismuth hydroxide, and bismuth carbonate; and the europium source includes one or more of europium oxide, europium nitrate, europium hydroxide, and europium carbonate.

4. The preparation method according to claim 2 or 3, characterized in that, The mixing method is grinding.

5. The preparation method according to claim 4, characterized in that, The grinding process involves adding a grinding medium, which is ethanol.

6. The application of the apatite-structured silicate phosphor according to claim 1 or the apatite-structured silicate phosphor prepared by any one of claims 2 to 5 in the fields of solid-state lighting, optical temperature sensing and temperature visualization.

7. The application according to claim 6, characterized in that, The solid-state lighting includes white LEDs, and the optical temperature sensing includes non-contact optical temperature measurement devices.

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