Temperature sensing material based on dual-mode thermal response up-conversion luminescence and preparation method and application thereof

Abstract

The invention discloses a temperature sensing material based on dual-mode thermal response up-conversion luminescence and a preparation method and application thereof, and belongs to the technical field of optical temperature sensing. The chemical formula of the material is Bi (4-y) Ti (0.5) M (0.5) O8X: REy, wherein M is W or Mo, X is Cl or Br, RE is Er or Yb / Er, and a hydrothermal-molten salt method series synthesis strategy is adopted for preparation. Different from a traditional thermal quenching material, according to the dual-mode thermal response up-conversion luminescence temperature sensing material Bi4Ti0. 5M0. 5O8X, visible light is weakened along with temperature rise, and meanwhile 800 nm near-infrared luminescence is enhanced. By utilizing the characteristic that the up-conversion luminescence intensity has opposite response to temperature change, the up-conversion temperature sensing material disclosed by the invention has relatively high optical temperature sensitivity in a fluorescence intensity mode and a fluorescence lifetime mode, and is an optical temperature sensing material with a wide temperature measurement range, which can be used for high-temperature environment detection; the method has great application potential in the field of optical temperature sensing.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical temperature sensing, and in particular relates to a temperature sensing material based on dual-mode thermal response up-conversion luminescence, and a preparation method and application thereof. Background Art

[0002] Rare earth upconversion luminescent materials have the advantages of strong visible light emission, long life, fast response, non-contact, strong anti-interference ability, and high temperature measurement resolution. They have broad application prospects in optical temperature measurement. Among them, the temperature sensing of fluorescence intensity ratio (FIR) technology is a detection technology that uses the relationship between the ratio of the intensity of two luminescence peaks and the temperature change to reflect the surrounding environment. It is currently the most studied and widely used optical temperature measurement technology. With the development of fluorescence temperature sensing technology, people have put forward higher and higher requirements on the performance of upconversion luminescent materials, especially the upconversion luminescence efficiency. In addition to luminescence efficiency, the thermal stability of luminescence of the material is also an important indicator to measure whether it can be applied in practice. However, the luminescence efficiency of most rare earth upconversion luminescent materials will decrease significantly with the increase of temperature, that is, fluorescence thermal quenching occurs, which seriously hinders its application in optical temperature sensing.

[0003] Generally speaking, high temperature causes fluorescence quenching of luminescent materials mainly because as the temperature rises, the vibration of the matrix lattice intensifies, leading to enhanced electron-phonon interaction and increased non-radiative transition rate, thus causing a decrease in luminescence intensity and lifetime.

[0004] Sillen-Aurivillius perovskite-structured layered Bi4M 0.5 Ti 0.5 O8X (M=W, Mo; X=Cl, Br), its [Bi2O2] 2+ The layers and staggered negatively charged ions / polyhedron layers are connected by van der Waals forces and form a built-in electric field. In the two-dimensional layered crystals formed by van der Waals forces, phonons have a more efficient migration ability along the two-dimensional structure of the material, while electrons are mainly transmitted and migrated in the three-dimensional direction. The existing built-in electric field will induce directional migration of electrons, thereby reducing the coupling degree of phonons and electrons at high temperatures, achieving a certain degree of acoustic-electric decoupling, and effectively suppressing phonon scattering. Therefore, when the above factors work together, it is possible to achieve anomalous thermally enhanced luminescence of rare earth ions by regulating the electron-phonon coupling effect through the built-in electric field, thereby reducing the phonon scattering effect and suppressing the non-radiative relaxation process at high temperatures. Among them, Er 3+ The ion has rich energy levels and an emission spectrum covering a wide range of wavelengths from deep ultraviolet to near infrared, making it particularly attractive. 3+Related research focuses on blue, green, and red emission bands, while the 800nm ​​near-infrared emission band cannot be detected because it is too weak. 4 I 9 / 2 - 4 I 15 / 2 The transition seems to have been ignored for a long time, and there are even fewer studies on its thermally enhanced luminescence. It is of great significance to introduce Er into perovskite layered materials to study its 800nm ​​near-infrared thermally enhanced luminescence. At the same time, this new material also provides an effective way to improve the fluorescence temperature measurement method. Summary of the invention

[0005] In order to solve the problem of serious thermal quenching and low luminescence efficiency of existing up-conversion materials, one of the purposes of the present invention is to provide a dual-mode thermal response up-conversion luminescence temperature sensing material, the chemical formula of the material is: Bi 4-y Ti 0.5 M 0.5 O8X:RE y , wherein y=0.01-0.2, M is W or Mo, X is Cl or Br, RE is Er or Yb / Er, when rare earth ions are singly doped, RE is Er, and when rare earth ions are doped twice, RE is Yb / Er.

[0006] Bi4M 0.5 Ti 0.5 O8X, an upconversion material with dual-mode thermal response and near-infrared luminescence thermal enhancement was obtained. At 293K~493K, the best absolute sensitivity and relative sensitivity were 72.26%K -1 and 8.27% K -1 .

[0007] Another object of the present invention is to provide a method for preparing a dilute dual-mode thermal response upconversion luminescence temperature sensing material, comprising the following steps:

[0008] (1) dissolving a bismuth source in a mannitol solvent, stirring and mixing, adding an aqueous solution of a halide, subjecting the resulting mixed solution to a hydrothermal reaction, centrifuging, washing, and drying to obtain a BiOX precursor, wherein X is Cl or Br;

[0009] (2) BiOX, Bi2O3, MO3, TiO2 and rare earth ions are mixed evenly, and then NaCl and KCl are added to fully grind and stir to obtain a mixture, and the mixture is sintered, washed and dried to obtain Bi 4-y Ti 0.5 M 0.5 O8X:RE y Phosphor, wherein y=0.01-0.2, M is W or Mo, X is Cl or Br, and RE is Er or Yb / Er.

[0010] Preferably, the molar volume ratio of the bismuth source to the mannitol solution in step (1) is (0.05-0.1):30, unit mol:mL; the bismuth source is one of Bi(NO3)3·5H2O, CBi2O5, Bi2(SO4)3, Bi2O3, and BiPO4, and the molar concentration of the mannitol solvent is 0.1 mol / mL.

[0011] Preferably, in step (1), the volume ratio of the aqueous solution of the halide to the mannitol solvent is (2-3):30, the molar concentration of the aqueous solution of the halide is 2.5 mol / mL, and the halide is a halide containing Cl or Br.

[0012] Preferably, the hydrothermal reaction temperature in step (1) is 120° C. to 220° C., and the hydrothermal reaction time is 6 to 36 hours.

[0013] Preferably, the rare earth ion source in step (2) is one or more of RECl3, RE2O3; and the rare earth ions are Er or Yb / Er.

[0014] Preferably, in step (2), the molar ratio of Bi2O3, BiOX, MO3, TiO2 and rare earth ions is (2.80-2.99):2:1:1:(0.01-0.3), wherein MO3 is WO3 or MoO3.

[0015] Preferably, the amount of NaCl and KCl added in step (2) is 1 to 20 times the total mass of BiOX, Bi2O3, MO3, TiO2, and rare earth ions, wherein the molar ratio of NaCl to KCl is 1:1.

[0016] Preferably, the sintering temperature in step (2) is 400-800° C., and the sintering is carried out in an air atmosphere for 1-24 hours.

[0017] The dual-mode thermal response up-conversion luminescent temperature sensing material prepared by the present invention is used in optical temperature sensing.

[0018] Beneficial effects of the present invention

[0019] (1) In the present invention, Bi 4-y Ti 0.5 M 0.5 O8X:RE y A temperature sensing material based on dual-mode thermal response upconversion luminescence has good luminescence properties, stable physical and chemical properties, simple preparation method, mild reaction conditions, and low raw material cost. This material is expected to be used as a highly sensitive optical anti-counterfeiting material, ultraviolet detector, temperature sensor, photovoltaic ferroelectric material, and optomechanical material sensing material.

[0020] (2) The dual-mode thermal response upconversion luminescence temperature sensing material prepared by the present invention exhibits strong luminescence intensity, and at the same time, as the temperature increases, Er 3+ The ions exhibit opposite thermal responses in the visible and near-infrared emission bands, and achieve thermal enhancement of 800nm ​​near-infrared luminescence. This opposite response characteristic can effectively improve the sensitivity of optical temperature sensing, which is of great significance for the design and development of accurate and efficient optical thermometers.

[0021] (3) Bi prepared by the present invention 4-y Ti 0.5 M 0.5 O8X:RE y It has high optical temperature sensitivity in both fluorescence intensity mode and fluorescence lifetime mode. It is an optical temperature sensing material with a wide temperature measurement range that can be used for high-temperature environment detection and has great application potential in the field of optical temperature sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a comparison diagram of the X-ray diffraction pattern of the dual-mode thermal response upconversion luminescence temperature sensing material prepared in Examples 1 to 5 and a standard card.

[0023] Figure 2 This is a comparison chart of upconversion emission spectra of the dual-mode thermal response upconversion luminescent temperature sensing materials prepared in Examples 1 to 5 under 980nm excitation.

[0024] Figure 3 This is the up-conversion temperature-variable emission spectrum of the dual-mode thermal response up-conversion luminescent temperature sensing material prepared in Example 3 under 980nm excitation.

[0025] Figure 4 for Figure 3 Fitting of the non-thermal coupled temperature sensitivity factors of near-infrared and green light in the up-conversion variable temperature emission spectrum under 980nm excitation. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0027] Example 1

[0028] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.99 Ti 0.5 W 0.5 O8Cl:Er 0.01 , the preparation method is as follows:

[0029] (1) 0.05 mol of Bi(NO3)3·5H2O was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a KCl solution with a concentration of 2.5 mol / mL was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 120°C for 6 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOCl precursor.

[0030] (2) Bi2O3, BiOCl, WO3, TiO2, and Er2O3 were mixed in a molar ratio of 2.99:2:1:1:0.01, and the amount of NaCl and KCl added was 1 times the total mass of Bi2O3, BiOCl, WO3, TiO2, and Er2O3. After being fully ground, the mixture was transferred to a crucible and sintered at 600°C for 6 hours. The mixture was naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.99 Ti 0.5 W 0.5 O8Cl:Er 0.01 .

[0031] Example 2

[0032] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.95 Ti 0.5 W 0.5 O8Cl:Er 0.05 , the preparation method is as follows:

[0033] (1) 0.1 mol of CBi2O5 was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 3 mL of a KCl solution with a concentration of 2.5 mol / mL was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 160°C for 12 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOCl precursor.

[0034] (2) Bi2O3, BiOCl, WO3, TiO2, and Er2O3 were mixed in a molar ratio of 2.95:2:1:1:0.05, and the amount of NaCl and KCl added was 3 times the total mass. After being fully ground, they were transferred to a crucible and sintered at 660°C for 8 hours, naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.95 Ti 0.5 W 0.5 O8Cl:Er0.05

[0035] Example 3

[0036] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.90 Ti 0.5 W 0.5 O8Cl:Er 0.1 , the preparation method is as follows:

[0037] (1) 0.05 mol of BiPO4 was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a solution of NaCl with a concentration of 2.5 mol / mL was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 180°C for 14 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOCl precursor.

[0038] (2) Bi2O3, BiOCl, WO3, TiO2, and Er2O3 were mixed in a molar ratio of 2.90:2:1:1:0.1, and the amount of NaCl and KCl added was 5 times the total mass. After being fully ground, they were transferred to a crucible and sintered at 700°C for 10 hours, naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.9 Ti 0.5 W 0.5 O8Cl:Er 0.1 .

[0039] Example 4

[0040] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.85 Ti 0.5 W 0.5 O8Cl:Er 0.15 , the preparation method is as follows:

[0041] (1) 0.05 mol of Bi(NO3)3·5H2O was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a KCl solution with a concentration of 2.5 mol / mL was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 200°C for 18 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOCl precursor.

[0042] (2) Bi2O3, BiOCl, WO3, TiO2, and ErCl3 were mixed in a molar ratio of 2.85:2:1:1:0.3, and the amount of NaCl and KCl added was 7 times the total mass. After being fully ground, the mixture was transferred to a crucible and sintered at 750°C for 12 hours. The mixture was naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.85 Ti 0.5 W 0.5 O8Cl:Er 0.15 .

[0043] Example 5

[0044] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.8 Ti 0.5 W 0.5 O8Cl:Er 0.2 , the preparation method is as follows:

[0045] (1) 0.05 mol of Bi(NO3)3·5H2O was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a 2.5 mol / mL KCl solution was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 220°C for 24 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOCl precursor.

[0046] (2) Bi2O3, BiOCl, WO3, TiO2, and Er2O3 were mixed in a molar ratio of 2.80:2:1:1:0.2, and the amount of NaCl and KCl added was 10 times the total mass. After being fully ground, they were transferred to a crucible and sintered at 800°C for 24 hours, naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.8 Ti 0.5 W 0.5 O8Cl:Er 0.2 .

[0047] Example 6

[0048] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.8 Ti 0.5 W 0.5 O8Cl:Er 0.1 Yb 0.1 , the preparation method is as follows:

[0049] (1) 0.05 mol of Bi(NO3)3·5H2O was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a KCl solution with a concentration of 2.5 mol / mL was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 160°C for 6 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and pure ethyl acetate, respectively, and then dried at 70°C to obtain a BiOCl precursor.

[0050] (2) Bi2O3, BiOCl, WO3, TiO2, Er2O3, and Yb2O3 were mixed in a molar ratio of 2.8:2:1:1:0.1:0.1, and the amount of NaCl and KCl added was 5 times the total mass. After being fully ground, the mixture was transferred to a crucible and sintered at 660°C for 18 hours, naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.8 Ti 0.5 W 0.5 O8Cl:Er 0.1 , Yb 0.1 .

[0051] The sample prepared in this example has similar optical properties to the sample in Example 3, and also has the 800nm ​​thermal enhancement phenomenon.

[0052] Example 7

[0053] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.8 Ti 0.5 W 0.5 O8Br:Er 0.1 Yb 0.1 , the preparation method is as follows:

[0054] (1) 0.05 mol of Bi(NO3)3·5H2O was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a KBr solution with a concentration of 2.5 mol / mL was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 160°C for 6 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and pure ethyl acetate, respectively, and then dried at 70°C to obtain a BiOBr precursor.

[0055] (2) Bi2O3, BiOCl, WO3, TiO2, Er2O3, and Yb2O3 were mixed in a molar ratio of 2.8:2:1:1:0.1:0.1, and the amount of NaCl and KCl added was 5 times the total mass. After being fully ground, the mixture was transferred to a crucible and sintered at 660°C for 20 hours. The mixture was naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.8 Ti 0.5 W 0.5 O8Cl:Er 0.1， Yb 0.1 .

[0056] Example 8

[0057] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.99 Ti 0.5 W 0.5 O8Br:Er 0.01 , the preparation method is as follows:

[0058] (1) 0.05 mol of Bi2O3 was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a KBr solution with a concentration of 2.5 mol / mL was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 160°C for 36 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOBr precursor.

[0059] (2) Bi2O3, BiOBr, WO3, TiO2, and Er2O3 were mixed in a molar ratio of 2.99:2:1:1:0.01, and the amount of NaCl and KCl added was 12 times the total mass. After being fully ground, the mixture was transferred to a crucible and sintered at 680°C for 12 hours, naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.99 Ti 0.5 W 0.5 O8Br:Er 0.01 .

[0060] Example 9

[0061] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.99 Ti 0.5 W 0.5 O8Br:Er 0.01 , the preparation method is as follows:

[0062] (1) 0.05 mol of Bi2O3 was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a 2.5 mol / mL NH4Cl solution was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 160°C for 12 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOBr precursor.

[0063] (2) Bi2O3, BiOBr, WO3, TiO2, and Er2O3 were mixed in a molar ratio of 2.95:2:1:1:0.5, and the amount of NaCl and KCl added was 16 times the total mass. After being fully ground, they were transferred to a crucible and sintered at 680°C for 12 hours, naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.95 Ti 0.5 W 0.5 O8Br:Er 0.05 .

[0064] Example 10

[0065] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.99 Ti 0.5 Mo 0.5 O8Cl:Er 0.01 , the preparation method is as follows:

[0066] (1) 0.05 mol of Bi2(SO4)3 was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a 2.5 mol / mL NH4Cl solution was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 180°C for 12 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOCl precursor.

[0067] (2) Bi2O3, BiOBr, MoO3, TiO2, and Er2O were mixed in a molar ratio of 2.99:2:1:1:0.01, and the amount of NaCl and KCl added was 18 times the total mass. After being fully ground, they were transferred to a crucible and sintered at 680°C for 12 hours, naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.99 Ti 0.5 Mo 0.5 O8Cl:Er 0.01 .

[0068] Embodiment 11

[0069] The chemical formula of the temperature sensing material of the dual-mode thermal response upconversion luminescence in this embodiment is Bi 3.99 Ti 0.5 Mo 0.5 O8Br:Er 0.01 , the preparation method is as follows:

[0070] (1) 0.05 mol of Bi(NO3)3·5H2O was added to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, and the solution was stirred until it became transparent. Then, 2 mL of a 2.5 mol / mL KCl solution was added and stirred thoroughly to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 160°C for 24 hours. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a precipitate. The precipitate was washed by centrifugation with deionized water and ethanol, respectively, and then dried at 70°C to obtain a BiOCl precursor.

[0071] (2) Bi2O3, BiOBr, MoO3, TiO2, and Er2O3 were mixed in a molar ratio of 2.99:2:1:1:0.01, and the amount of NaCl and KCl added was 20 times the total mass. After being fully ground, they were transferred to a crucible and sintered at 700°C for 6 hours. The mixture was naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 3.99 Ti 0.5 Mo 0.5 O8Br:Er 0.01 .

[0072] Comparative Example 1

[0073] In this embodiment, a chemical formula of NaYF4:20%Yb 3+ , 2%Er 3+ The materials were prepared as follows:

[0074] (1) Add a standard solution of RE(NO3)3 (Y / Yb / Er1 / 478:20:2, 2 mmol in total) dropwise to an 8 mL aqueous solution containing 2 mmol of EDTA-2Na to obtain a chelated RE-EDTA complex. After stirring for 30 minutes, add 28 mL of an aqueous solution containing 25 mmol of NaF to the above solution and stir for 1 hour to obtain a mixed solution. Transfer the mixed solution to a polytetrafluoroethylene reactor and perform a hydrothermal reaction at 180°C for 24 hours. After the reaction is completed, cool naturally to room temperature to obtain a precipitate. Wash the precipitate with deionized water and pure ethyl acetate by centrifugation, and then dry at 70°C to obtain NaYF4:20%Yb 3+ , 2%Er 3+ .

[0075] Compared with the material prepared in Example 3, the material prepared in this comparative example has no 800nm ​​thermal enhancement phenomenon.

[0076] Comparative Example 2

[0077] In this embodiment, a chemical formula of Bi 11.9 O 17 Br2:Er 0.1 The materials, preparation method and dosage of each substance are the same as those in Example 3, as follows:

[0078] (1) Add 0.05 mol Bi(NO3)3·5H2O to 30 mL of an aqueous solution of mannitol with a molar concentration of 0.1 mol / mL, stir until the solution is transparent, then add 2 mL of a 2.5 mol / mL KBr solution, stir thoroughly to obtain a mixed solution. Transfer the mixed solution to a polytetrafluoroethylene reactor, perform a hydrothermal reaction at 160°C for 24 hours, and cool naturally to room temperature after the reaction is completed to obtain a precipitate. Wash the precipitate with deionized water and pure ethyl acetate by centrifugation, and then dry at 70°C to obtain a BiOBr precursor.

[0079] (3) Bi2O3, BiOBr, and Er2O3 were mixed in a molar ratio of 5:2:0.1, and the amount of NaCl and KCl added was 5 times the total mass. After being fully ground, they were transferred to a crucible and sintered at 720°C for 8 hours. The mixture was naturally cooled to room temperature, washed with warm water, and dried at 70°C to obtain Bi 11.9 O 17 Br2:Er 0.1 .

[0080] Compared with the material prepared in Example 3, the material prepared in this comparative example does not have strong up-conversion luminescence intensity and 800nm ​​near-infrared thermal enhancement phenomenon.

[0081] Performance Testing

[0082] The materials prepared in Examples 1 to 5 were subjected to relevant performance tests. First, the prepared materials were subjected to X-ray diffraction analysis. The results are as follows: Figure 1 As shown in the figure, it can be seen that the samples synthesized with different Er doping concentrations are all pure phases, and changing the conditions and doping concentrations does not affect their phase purity.

[0083] The prepared material was subjected to up-conversion emission spectrum analysis under 980nm excitation light, and the results are as follows: Figure 2 As shown in the figure, it can be seen that the luminescence intensity first increases and then decreases with the increase of doping concentration. In Example 3, the luminescence is strongest when the doping concentration is 10%.

[0084] The material prepared in Example 3 was subjected to up-conversion temperature-dependent emission spectroscopy analysis under 980nm excitation. The results are as follows: Figure 3 As shown in the figure, it can be seen that as the temperature increases from 293K to 493K, the green light emission at 524nm, 542nm and the red light emission at 670nm and the near-infrared emission intensity at 800nm ​​show completely opposite changes. The green and red light emission intensities continue to weaken with increasing temperature, while the near-infrared emission at 800nm ​​continues to increase with increasing temperature.

[0085] The material prepared in Example 3 was subjected to the up-conversion temperature-variable emission spectrum under 980nm excitation and the near-infrared and green light non-thermal coupling temperature sensitivity factor fitting. The results are as follows: Figure 4 As shown in the figure, it can be seen that its relative sensitivity (Sr) is the maximum value of 8.27% K at 298K -1 The absolute sensitivity (Sa) is 72.26% K at 493 K. -1 .

Claims

1. A temperature sensing material based on dual-mode thermal response upconversion luminescence, characterized in that: Its chemical formula is: Bi 4- y Ti 0.5 M 0.5 O8X:RE y , wherein y=0.01-0.2, M is W or Mo, X is Cl or Br, and RE is Er or Yb / Er.

2. The method for preparing the temperature sensing material based on dual-mode thermal response upconversion luminescence according to claim 1, characterized in that: The following steps are involved: (1) dissolving a bismuth source in a mannitol solvent, stirring and mixing, adding an aqueous solution of a halide, subjecting the resulting mixed solution to a hydrothermal reaction, centrifuging, washing, and drying to obtain a BiOX precursor, wherein X is Cl or Br; (2) BiOX, Bi2O3, MO3, TiO2 and rare earth ions are mixed evenly, and then NaCl and KCl are added to fully grind and stir to obtain a mixture, and the mixture is sintered, washed and dried to obtain Bi 4-y Ti 0.5 M 0.5 O8X:RE y Phosphor, wherein y=0.01-0.2, M is W or Mo, X is Cl or Br, and RE is Er or Yb / Er.

3. The method for preparing a temperature sensing material based on dual-mode thermal response upconversion luminescence according to claim 2, characterized in that: The molar volume ratio of the bismuth source to the mannitol solution in step (1) is (0.05-0.1):30, unit mol:mL; the bismuth source is one of Bi(NO3)3·5H2O, CBi2O5, Bi2(SO4)3, Bi2O3, and BiPO4, and the molar concentration of the mannitol solvent is 0.1 mol / mL.

4. The method for preparing a temperature sensing material based on dual-mode thermal response upconversion luminescence according to claim 2, characterized in that: In step (1), the volume ratio of the aqueous solution of the halide to the mannitol solvent is (2-3):30, the molar concentration of the aqueous solution of the halide is 2.5 mol / mL, and the halide is a halide containing Cl or Br.

5. The method for preparing a temperature sensing material based on dual-mode thermal response upconversion luminescence according to claim 2, characterized in that: The hydrothermal reaction temperature in step (1) is 120° C. to 220° C., and the hydrothermal reaction time is 6 to 36 hours.

6. The method for preparing a temperature sensing material based on dual-mode thermal response upconversion luminescence according to claim 2, characterized in that: The rare earth ion source in step (2) is one or more of RECl3 and RE2O3; the rare earth ions are Er or Yb / Er.

7. The method for preparing a temperature sensing material based on dual-mode thermal response upconversion luminescence according to claim 2, characterized in that: In step (2), the molar ratio of Bi2O3, BiOX, MO3, TiO2 and rare earth ions is (2.80-2.99):2:1:1:(0.01-0.3), wherein MO3 is WO3 or MoO3.

8. The method for preparing a temperature sensing material based on dual-mode thermal response upconversion luminescence according to claim 2, characterized in that: In step (2), the amount of NaCl and KCl added is 1 to 20 times the total mass of BiOX, Bi2O3, MO3, TiO2 and rare earth ions, wherein the molar ratio of NaCl to KCl is 1:

1.

9. The method for preparing a temperature sensing material based on dual-mode thermal response upconversion luminescence according to claim 2, characterized in that: The sintering temperature in step (2) is 400-800° C., and the sintering is carried out in an air atmosphere for 1-24 hours.

10. Application of the temperature sensing material based on dual-mode thermal response upconversion luminescence as claimed in claim 1 in optical temperature sensing.

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