Rare earth ion doped (Eu < 3 + >, Tm < 3 + > or Tb < 3 + >) Y2Mo3O12 temperature sensing fluorescent powder

Abstract

The invention belongs to the field of inorganic nano functional material application, and relates to rare earth ion doped (Eu < 3 + >, Tm < 3 + > or Tb < 3 + >) Y2Mo3O12 temperature sensing fluorescent powder and a preparation method thereof. Y2Mo3O12 is a typical negative thermal expansion material, the Y2Mo3O12 fluorescent powder doped with Eu < 3 + >, Tm < 3 + > or Tb < 3 + > ions with different concentrations is prepared through a high-temperature solid-phase reaction method, and the temperature response sensitivity of the fluorescent powder can be improved by utilizing the temperature influence on the non-radiation rate of rare earth ions and the negative thermal expansion characteristic of a matrix. The fluorescent powder disclosed by the invention can be excited by ultraviolet light near 365 nm, a main emission peak can be in any range of red, green and blue light bands according to doped ion types, and temperature sensing of the fluorescent powder can be obtained by utilizing the change of the intensity of a single emission peak or the relative intensity of double emission peaks along with temperature. The invention is expected to provide novel high-sensitivity temperature sensing fluorescent powder and a sensitivity improving strategy.

Description

Technical Field

[0001] The present invention belongs to the application field of inorganic nano functional materials and relates to a rare earth ion doped (Eu 3+ , Tm 3+ or Tb 3 + )Y2Mo3O 12 Temperature sensing phosphor and preparation method thereof. Background Art

[0002] Rare earth ions have unique electronic layer structures and excellent spectral properties, and their emission spectra cover almost the entire visible light spectrum. Rare earth-doped luminescent materials are one of the commonly used luminescent materials, which are composed of luminescent centers (activators) and matrix materials. The fluorescence intensity of rare earth-doped luminescent materials usually shows obvious thermal quenching phenomenon as the temperature rises (the phenomenon of decreasing luminescence intensity as the temperature rises). The main reason for this phenomenon is that under the condition of increasing temperature, the vibration of the matrix lattice is enhanced, resulting in enhanced interaction between phonons and electrons, and at the same time, the non-radiative transition rate increases, resulting in a decrease in luminescence intensity and a decrease in fluorescence lifetime. The characteristic of rare earth luminescent materials that the luminescence spectrum or fluorescence lifetime changes due to temperature makes them a potential temperature sensing material for non-contact temperature measurement. Rare earth luminescence temperature sensing is not only related to the energy level structure of the rare earth ions themselves, but also to the matrix environment in which they are located. Reasonable selection and design of the structural composition of the phosphor is expected to achieve an improvement in temperature sensitivity.

[0003] Generally speaking, as the temperature rises, the non-harmonic vibration of the material will increase the distance between atoms, which is why most materials have the property of "thermal expansion and contraction". Negative thermal expansion materials are just the opposite. As the temperature rises, their volume decreases. Its internal mechanism is very complex and is generally believed to be caused by non-vibration effects such as the phonon vibration effect of the material or the phase transition of the material's magnetic structure and the crystal charge transfer mechanism. It is precisely because of the unique properties of negative thermal expansion materials that rare earth ion-doped materials may have special temperature-dependent optical properties. The reduction in the volume of the matrix lattice under high temperature conditions will shorten the distance between the sensitizer and the activator, thereby increasing the probability of interaction between ions. The distortion of the lattice will also affect the luminescence efficiency of the material at high temperatures to a certain extent.

[0004] Y2Mo3O 12 It is a rare earth molybdate material with negative thermal expansion effect and belongs to A2M3O 12 (where A represents a trivalent cation and M is an element such as Mo or W) type negative thermal expansion material. A2M3O 12 It has two crystal structures: tetrahedral structure and orthorhombic structure, of which the orthorhombic structure has negative thermal expansion properties.12 As a matrix, it can provide a larger solubility of the luminescent center, a higher luminescent efficiency, and is easily regulated by the temperature field. Therefore, the rare earth ion doped Y2Mo3O 12 It has broad application prospects in the field of fluorescence temperature sensing.

[0005] In terms of papers, in 2021, Yuanming Yang et al. prepared Y2Mo3O 12 :Er 3+ , Yb 3+ Upconversion phosphor (Journal of Luminescence, 2021, 240, 118410), using Er from room temperature to 753K 3+ The fluorescence intensity ratio of upconversion emission was analyzed for Y2Mo3O 12 :Er 3+ , Yb 3+ Temperature sensing properties of the phosphor. The negative thermal expansion phenomenon of this phosphor above 393K has been confirmed, and the upconversion emission at high temperature is greatly enhanced even in the case of thermal quenching. The maximum absolute sensitivity and relative sensitivity of this temperature sensing phosphor reach 1.303*10 -2 K -1 and 1.139% K -1 .

[0006] In summary, in recent years, although Y2Mo3O 12 The synthesis method and temperature sensing of the material have received attention, but they mainly use up-conversion luminescence, which has low luminescence efficiency and high requirements for equipment. 12 The research on the preparation method of the material and its temperature sensing has not been reported, and no patents related to it have been published. The present invention prepares Eu doped with different concentrations by high temperature solid phase reaction method 3+ , Tm 3+ or Tb 3+ Ionic Y2Mo3O 12 Phosphors, by utilizing the fact that the non-radiative rate of rare earth ions is affected by temperature and the negative thermal expansion characteristics of the matrix, can improve the temperature response sensitivity of the phosphors. The phosphors involved in the present invention can be excited by ultraviolet light near 365nm, and the main emission peak can be in any range of the red, green, and blue light bands according to the type of doped ions. Its temperature sensing can be obtained by using the change of the single emission peak intensity or the relative intensity of the double emission peaks with temperature. The present invention is expected to provide a new type of high-sensitivity temperature sensing phosphor and a sensitivity improvement strategy. Summary of the invention

[0007] The purpose of the present invention is to provide a rare earth ion doped (Eu 3+ , Tm3+ or Tb 3+ )Y2Mo3O 12 Temperature sensing phosphor and preparation method thereof.

[0008] The chemical formula of the rare earth ion doped cubic zirconium tungstate upconversion nanocrystals of the present invention is: Y2Mo3O 12 :RE 3+ (RE 3+ For Eu 3+ Tm 3+ , Tb + one of them).

[0009] The rare earth ion doped Y2Mo3O 12 The crystal phase of the temperature sensing phosphor is an orthorhombic phase.

[0010] The rare earth ion doped Y2Mo3O 12 The temperature sensing phosphor can perform down-shift luminescence. Under the excitation of ultraviolet light near 365nm, its luminescence spectrum covers the red, blue and green light bands respectively depending on the doped ions.

[0011] The rare earth ion doped Y2Mo3O 12 The preparation method of the temperature sensing phosphor comprises the following steps:

[0012] (1) Calculation. Determine the total mass or amount of substance of the product. 24 Mo7N6O 24 4H2O (99.9%) was used as the sample powder matrix raw material, and Tm2O3 (99.99%), Tb2O3 (99.5%) or Eu2O3 (99.99%) were used as the sample powder rare earth doping ion raw materials. The doping ratio of rare earth ions (0.5mol%-20mol%) was determined, and the mass required for each raw material was calculated according to the product structure. It should be noted that the doping ions were considered to replace the Y atoms in the matrix;

[0013] (2) Weighing. Weigh each raw material using a balance according to the mass of each raw material calculated in step 1, and grind it evenly in an agate mortar;

[0014] (3) High-temperature solid-phase reaction. The uniform powder obtained in step 2 is placed in an alumina crucible, and then placed in a muffle furnace and fired at high temperature for several hours. After the temperature drops to room temperature, the sample is taken out and placed in an agate mortar for grinding and packaging. The sample preparation is completed.

[0015] The present invention has the following beneficial effects:

[0016] The rare earth ion doped Y2Mo3O12 Temperature sensing phosphors can perform down-shift luminescence, converting ultraviolet or short-wavelength excitation light into visible light emission with a longer wavelength. At the same time, it is expected to combine with orthorhombic phase Y2Mo3O 12 The negative thermal expansion property of the material improves the sensitivity of temperature sensing. 12 The preparation method of temperature sensing phosphor has the advantages of low experimental cost, low reaction energy consumption, simple and controllable preparation process, high reaction yield, high product purity and uniform product crystal phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The orthorhombic phase Y2Mo3O of Example 1 of the present invention 12 : X-ray diffraction pattern of 15mol% Eu phosphor;

[0018] Figure 2 The orthorhombic phase Y2Mo3O of Example 1 of the present invention 12 : Fluorescence spectrum of 15mol% Eu phosphor at different excitation wavelengths;

[0019] Figure 3 The orthorhombic phase Y2Mo3O of Example 1 of the present invention 12 : Fluorescence emission spectrum of 15 mol% Eu phosphor under variable temperature. DETAILED DESCRIPTION

[0020] The content of the invention of the present invention is further described below in conjunction with the accompanying drawings and examples. These embodiments should be understood to be used only to illustrate the present invention and not to limit the scope of protection of the present invention. After reading the contents recorded in the present invention, various changes or modifications made to the present invention based on the principles of the present invention also fall within the scope defined by the claims of the present invention. At the same time, the technical scheme of the present invention is not limited to the specific embodiments listed below, but also includes any combination of reaction conditions of each specific embodiment; it is not limited to the specific reaction reagents listed below, but also includes any combination of the same type and the same family of reagents; it is not limited to the specific fluorescence spectrum test method and temperature sensing analysis method listed below, but also includes any combination of the same type of fluorescence spectrum, variable temperature fluorescence spectrum test and analysis method.

[0021] Example 1: Synthesis of Y2Mo3O in this embodiment 12 :Eu phosphor and temperature spectrum test method are implemented according to the following steps:

[0022] (1) Weigh 0.1919 g and 0.5297 g of Y2O3 (99.99%) and H 24 Mo7N6O 244H2O (99.9%) solid powder was fully ground in a mortar for 10 minutes. 0.0528 g of Eu2O3 was weighed and added to the above powder. The mixture was ground for 10 minutes until it was evenly mixed.

[0023] (2) The uniform powder obtained above is placed in an alumina crucible, and then placed in a muffle furnace and fired at 800°C for 4 hours. After the temperature drops to room temperature, the sample is taken out and placed in an agate mortar for grinding and packaging. The sample preparation is completed.

[0024] (3) Conduct X-ray diffraction tests on the laboratory’s samples.

[0025] (4) The laboratory samples are encapsulated in a variable temperature powder holder, placed in the sample compartment of the fluorescence spectrometer, and different temperatures are set. After the temperature stabilizes, the fluorescence spectrum test is performed.

Claims

1. A rare earth ion doping (Eu 3+ , Tm 3+ or Tb 3+ )Y2Mo3O 12 Temperature sensing phosphor, characterized in that: The crystal structure of the phosphor is orthorhombic phase, and the doping ion is Eu. 3+ , Tm 3+ or Tb 3+ One of the above, with a doping concentration between 0.5mol% and 20mol%.

2. A rare earth ion doping (Eu according to claim 1 3+ , Tm 3+ or Tb 3+ )Y2Mo3O 12 The method for preparing temperature sensing phosphor is characterized by: The preparation method adopts a high-temperature solid phase method, the preparation temperature is between 750-900°C, and the high-temperature reaction time is 2-10 hours.

3. A rare earth ion doping (Eu according to claim 1 3+ , Tm 3+ or Tb 3+ )Y2Mo3O 12 Temperature sensing phosphor, characterized in that: The phosphor can be excited by 360-370nm excitation light to generate Stokes luminescence.

4. A rare earth ion doping (Eu according to claim 1 3+ , Tm 3+ or Tb 3+ )Y2Mo3O 12 Temperature sensing phosphor, characterized in that: The main emission peaks of the phosphors are located in the red light (Eu 3+ ), Blue light (Tm 3+ ) or green light (Tb 3+ ) band.

5. A rare earth ion doping (Eu according to claim 1 3+ , Tm 3+ or Tb 3+ )Y2Mo3O 12 Temperature sensing phosphor, characterized in that: The fluorescence emission intensity of the phosphor changes with temperature, and the corresponding temperature range is from room temperature to 300°C.

6. A rare earth ion doping (Eu according to claim 1 3+ , Tm 3+ or Tb 3+ )Y2Mo3O 12 Temperature sensing phosphor, characterized in that: The temperature sensing characteristic of the phosphor can be realized according to the characteristics that the absolute fluorescence emission intensity (single peak) changes with temperature or the relative fluorescence emission intensity (double peak) changes with temperature.

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