ZnO-based up-conversion luminescence optical temperature measurement nano material and preparation method thereof

Abstract

The invention discloses a ZnO-based up-conversion luminescence optical temperature measurement nano material and a preparation method thereof. According to the preparation method, ZnO powder is taken as a raw material, Yb2O3 / Ho2O3, Yb2O3 / Er2O3 and Yb2O3 / Nd2O3 are respectively taken as doping agents, and the ZnO-based up-conversion luminescence optical temperature measurement nano material is prepared. The relative sensitivity of the prepared Yb < 3 + > / Ho < 3 + > co-doped ZnO optical temperature measurement material is up to 2.27% K <-1 >, the relative sensitivity of the Yb < 3 + > / Er < 3 + > co-doped ZnO optical temperature measurement material is up to 2.71% K <-1 >, and the relative sensitivity of the Yb < 3 + > / Nd < 3 + > co-doped ZnO optical temperature measurement material is up to 3.41% K <-1 >. The three kinds of up-conversion temperature measurement sensitivity prepared by the invention are all higher than that of most fluorescent temperature measurement materials, have unique advantages in non-contact and high sensitivity, and provide more possibilities for research and development of rare earth phosphor optical temperature measurement materials. The preparation method has the advantages of simplicity, low cost, high yield and the like, and is easy to industrialize.

Description

Technical Field

[0001] The present invention relates to the technical fields of nanomaterials, luminescent materials, temperature-sensitive materials, etc., and particularly relates to an up-conversion luminescence optical temperature measurement nanomaterial based on ZnO and a preparation method thereof. Background Art

[0002] In recent years, non-contact temperature detection technology, especially fluorescence intensity ratio temperature measurement technology based on the optical response of substances, has attracted much attention due to its unique advantages. This technology mainly relies on the intensity ratio of two or more fluorescence emission peaks of a phosphor at different temperatures for temperature measurement. Since this method is less interfered by measurement conditions, such as factors like fluorescence loss, excitation light source intensity fluctuation, and the distribution of luminescence centers have little impact on it, it has higher accuracy and reliability in practical applications.

[0003] Rare earth elements, with their unique electronic structures and rich energy level characteristics, have become indispensable luminescence centers in many optical materials. These characteristics not only endow rare earth elements with extensive applications in the fields of luminescence, lasers, displays, etc., but also enable them to exhibit characteristics that vary with the ambient temperature in certain optical properties, thus opening up new applications of rare earth-doped luminescent materials in the field of temperature measurement.

[0004] ZnO (zinc oxide) is a wide-bandgap semiconductor material (3.37 eV). It is a stable compound with high melting and boiling points, which enables it to maintain the integrity of its structure in a high-temperature environment, thus ensuring the stability and reliability of the temperature measurement material. It has excellent optical properties, such as high refractive index and light transmittance, which are conducive to the transmission and detection of fluorescence signals generated after rare earth element doping. After rare earth elements are doped into zinc oxide, a large amount of absorption and fluorescence information will be generated by the energy level pair transitions within the f-f configuration or between f-d of its electrons. These fluorescence signals have high sensitivity and resolution and can be used for precise temperature measurement. The doping of rare earth elements will also change the energy band structure and carrier concentration of zinc oxide, thereby further affecting its optical properties. This change may enable the doped zinc oxide material to have stronger fluorescence emission ability at a specific wavelength, thus improving the accuracy and sensitivity of temperature measurement.

[0005] Currently, there are many preparation methods for rare earth ion co-doped ZnO up-conversion luminescent materials, such as chemical combustion method, sol-gel method, chemical vapor deposition method, hydrothermal synthesis, co-precipitation method, etc. The above preparation methods for rare earth ion co-doped ZnO up-conversion luminescent materials have complex processes, long reaction times, high energy consumption, etc., and the prepared rare earth ion co-doped ZnO temperature sensitivity is relatively low.

[0006] To solve the above problems, the present invention is committed to preparing a rare earth ion co-doped ZnO optical temperature measurement material with high sensitivity and suitable for high-temperature environments by a simple method, and using a non-thermally coupled energy level for the optical temperature measurement method of fluorescence intensity ratio. On the one hand, it ensures that the material has high sensitivity, and on the other hand, it realizes the feasibility of the material being applied to high-temperature and high-heat environments. Summary of the Invention

[0007] The purpose of the present invention is to provide a rare earth-doped ZnO-based optical temperature measurement material and a preparation method, so as to solve the technical problem that it is difficult to prepare rare earth-doped ZnO-based optical temperature measurement materials in the prior art. The preferred technical solutions provided by the present invention and the many technical effects that can be produced are described in detail below.

[0008] To achieve the above purpose, the present invention provides the following technical solutions: an upconversion luminescence optical temperature measurement nanomaterial based on ZnO, with a chemical composition formula of ZnO: 1 mol% Yb 3+ , x mol% RE 3+ , where RE 3+ is Ho 3+ or Er 3+ or Nd 3+ ; x = 0.04 - 0.5.

[0009] Preferably, the material is composed of self-assembled nanorods to form a coral shape, the top of the nanorod is hexagonal pyramid-shaped, the length of the nanorod is 2 - 5 μm, and the diameter is 100 - 500 nm.

[0010] Preferably, the RE 3+ is Ho 3+ , and the fluorescence intensity ratio FIR of the non-thermally coupled energy levels 3+ F4, 5 S2- 5 I8 and 5 F5- 5 I8 of Ho 5 has a quantitative relationship with the temperature T: . Where A, B, and C represent constants, and T represents the absolute temperature. Further, the relative temperature sensitivity of the material reaches 2.27% K at 298 K -1 .

[0011] Preferably, the RE 3+ is Er 3+ , and the 3+ of Er 4 F 9 / 2 - 4 I 15 / 2The fluorescence intensity ratio FIR of the 622 nm emission peak and the 677 nm emission peak of the energy level has a quantitative relationship with the temperature T: . Where A, B, and C represent constants, and T represents the absolute temperature. Further, the relative temperature sensitivity of the material reaches 2.71% K at 298 K -1 .

[0012] Preferably, the RE 3+ is Nd 3+ , and the non-thermally coupled energy levels of Nd 3+ G 2 , 9 / 2 G 4 - 7 / 2 I 4 and 11 / 2 H 2 , 9 / 2 F 4 - 5 / 2 I 4 and 9 / 2 the fluorescence intensity ratio FIR of H . Where A, B, and C represent constants, and T represents the absolute temperature. Further, the relative temperature sensitivity of the material reaches 3.41% K at 298 K -1 .

[0013] All rare earth elements applied in the present invention have good luminescence properties. Therefore, the products prepared by using the above rare earth oxides as raw materials all have better application prospects in the optical field. ZnO, as a wide-bandgap semiconductor material, has good luminescence properties. And when it is used as a matrix material, due to its high melting point and boiling point, it can still maintain the structural integrity at high temperatures, thus ensuring the stability and reliability of the temperature measurement material. It provides more possibilities for the research and development of rare earth-doped ZnO-based optical temperature measurement materials.

[0014] The present invention also provides a preparation method of the above ZnO-based upconversion luminescence optical temperature measurement nanomaterial. The method includes mixing ZnO powder, Yb2O3 powder, and RE2O3 powder in a molar ratio of ZnO: Yb2O3: RE2O3 = 100:1: 0.04 - 0.5, placing them in a mold and pressing them into a block; placing it in a graphite crucible anode in the reaction chamber of a direct current arc discharge device, evacuating the reaction chamber and filling it with gas; performing discharge treatment, the gas pressure of the discharge gas is 50 - 60 kPa, the voltage range is 10 - 20 V, the current is 50 - 80 A, and the reaction time is 40 - 60 s; collecting the ZnO-based upconversion luminescence optical temperature measurement nanomaterial on the condensation wall.

[0015] Among them, the RE2O3 is Ho2O3 or Er2O3 or Nd2O3.

[0016] The preparation method of the present invention is simple and convenient to operate, highly efficient and energy-saving, with a large output. No catalyst needs to be added during the reaction process, and no harmful gas is discharged. The rare earth-doped ZnO-based optical temperature measurement material prepared by this method has a high purity, presents a hierarchical coral-like nanostructure, the top of the nanorods is hexagonal pyramid-shaped, and there are a large number of defects on its surface, which enhances the interaction between electrons and phonons. This characteristic leads to a more significant change trend of the fluorescence intensity ratio with temperature, thereby improving the sensitivity of the material to temperature changes. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0018] Figure 1 is a schematic structural diagram of the reaction device used in the method of the present invention; Figure 2 is ZnO:Yb prepared in Example 1 of the present invention 3+ / Ho 3+ XRD image of the optical temperature measurement material; Figure 3 is ZnO:Yb prepared in Example 1 of the present invention 3+ / Ho 3+ EDS image of the optical temperature measurement material; Figure 4 is ZnO:Yb prepared in Example 1 of the present invention 3+ / Ho 3+ SEM image of the optical temperature measurement material; Figure 5 is ZnO:Yb prepared in Example 1 of the present invention 3+ / Ho 3+ PL image of the optical temperature measurement material; Figure 6 is ZnO:Yb prepared in Example 1 of the present invention 3+ / Ho 3+ Variable-temperature luminescence image of the optical temperature measurement material; Figure 7 is ZnO:Yb prepared in Example 1 of the present invention 3+ / Ho 3+ Spectrum of fluorescence intensity ratio experiment and fitting data of the optical temperature measurement material; Figure 8 is ZnO:Yb prepared in Example 1 of the present invention 3+ / Ho 3+ Relative temperature sensitivity image of the optical temperature measurement material; Figure 9 is the XRD image of the ZnO:Yb 3+ / Er 3+ optical temperature measurement material prepared in Example 2 of the present invention; Figure 10 is the XRD image of the ZnO:Yb 3+ / Er 3+ EDS image of the optical temperature measurement material prepared in Example 2 of the present invention; Figure 11 is the XRD image of the ZnO:Yb 3+ / Er 3+ SEM image of the optical temperature measurement material prepared in Example 2 of the present invention; Figure 12 is the XRD image of the ZnO:Yb 3+ / Er 3+ PL image of the optical temperature measurement material prepared in Example 2 of the present invention; Figure 13 is the XRD image of the ZnO:Yb 3+ / Er 3+ Variable-temperature luminescence image of the optical temperature measurement material prepared in Example 2 of the present invention; Figure 14 is the XRD image of the ZnO:Yb 3+ / Er 3+ Spectrum of fluorescence intensity ratio experiment and fitting data of the optical temperature measurement material prepared in Example 2 of the present invention; Figure 15 is the XRD image of the ZnO:Yb 3+ / Er 3+ Relative temperature sensitivity image of the optical temperature measurement material prepared in Example 2 of the present invention; Figure 16 is the XRD image of the ZnO:Yb 3+ / Nd 3+ XRD image of the optical temperature measurement material prepared in Example 3 of the present invention; Figure 17 is the XRD image of the ZnO:Yb 3+ / Nd 3+ EDS image of the optical temperature measurement material prepared in Example 3 of the present invention; Figure 18 is the XRD image of the ZnO:Yb 3+ / Nd 3+ SEM image of the optical temperature measurement material prepared in Example 3 of the present invention; Figure 19 is the XRD image of the ZnO:Yb 3+ / Nd 3+ PL image of the optical temperature measurement material prepared in Example 3 of the present invention; Figure 20 is the XRD image of the ZnO:Yb 3+ / Nd 3+Variable-temperature luminescence image of the optical temperature measurement material; Figure 21 It is ZnO:Yb prepared in Example 3 of the present invention 3+ / Nd 3+ Fluorescence intensity ratio experiment and fitting data spectrogram of the optical temperature measurement material; Figure 22 It is ZnO:Yb prepared in Example 3 of the present invention 3+ / Nd 3+ Relative temperature sensitivity image of the optical temperature measurement material; Figure 1 In the figure: 1. Reaction chamber; 2. Condensing wall; 3. Tungsten cathode; 4. Reaction raw material; 5. Graphite crucible anode; 6. Copper seat (including water inlet and outlet); 7. Gas inlet; 8. Gas outlet; 9. Condensing wall water inlet; 10. Condensing wall water outlet. Specific implementation mode

[0019] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope protected by the present invention.

[0020] Figure 1 It is a schematic structural diagram of the reaction device used in the method of the present invention.

[0021] As Figure 1 shown, the reaction chamber 1 covers the condensing wall 2, the tungsten rod cathode 3 and the graphite crucible anode 5. Among them, the side of the graphite crucible anode 5 opposite to the tungsten rod cathode 3 is filled with the reaction raw material 4, and an arc is generated between the graphite crucible anode 5 and the tungsten rod cathode 3 by controlling the lifting of the copper seat 6. To ensure the smooth condensation of the reaction products, circulating cooling water is introduced at the graphite crucible anode 5 and the condensing wall 2. The copper seat 6 is both a water inlet and a water outlet, and the condensing wall 2 circulates the cooling water through the water inlet 9 and the water outlet 10. Before and after the reaction starts, reaction gases need to be introduced from the gas inlet 7 and the gas outlet 8 to play the roles of gas washing, filling reaction gases and passivation. Finally, the product is obtained at the graphite crucible anode 5.

[0022] Example 1 As Figures 2 - 8 shown, in this example, ZnO:Yb 3+ / Ho 3+ optical temperature measurement material was prepared, and the material preparation process is as follows: Mix ZnO powder, Yb2O3 and Ho2O3 evenly at a ratio of 100:1:0.3, then put them into a tablet press mold to press into an ingot 4 with a diameter of 1.8 cm and a height of 2 cm. Place the obtained ingot 4 in a graphite crucible 5 located in the reaction chamber of a DC arc discharge device, and fix the tungsten rod cathode 3 at a certain distance above the reaction raw material 4. After pumping the reaction chamber 1 to vacuum, fill the reaction chamber 1 with 60 kPa of oxygen as the reaction gas. Turn on the circulating water device and introduce cooling water from the copper seat 6 and the condensation wall 2. Adjust the height of the copper seat 6 to make the graphite crucible 5 contact the tungsten rod 3 and then pull apart instantly to start the arc discharge. During the discharge process, maintain the voltage at 20 V and the current at 80 A for 60 s. Collect ZnO:Yb 3+ / Ho 3+ upconversion luminescence optical temperature measurement nanomaterial. Figure 2 For this ZnO:Yb 3+ / Ho 3+ XRD image of the upconversion luminescence optical temperature measurement material. It can be seen from the figure that the diffraction peaks of this material belong to hexagonal wurtzite zinc oxide, and there are no rare earth oxide impurities. Figure 3 For this ZnO:Yb 3+ / Ho 3+ EDS energy spectrum of the upconversion luminescence optical temperature measurement material. According to the quantitative analysis of the EDS energy spectrum, the atomic ratio of Zn:O:Yb:Ho is about 41.63:44.81:4.99:0.24, indicating that the rare earth ions Yb 3+ and Ho 3+ are successfully doped into ZnO. Figure 4 For this ZnO:Yb 3+ / Ho 3+ SEM image of the upconversion luminescence optical temperature measurement material. It can be seen from the figure that the sample shows a hierarchical coral-like nanostructure. The top of the nanorods is hexagonal pyramidal, the length of the nanorods is 2 - 5 μm, and the diameter is 100 - 500 nm. Figure 5 For this ZnO:Yb 3+ / Ho 3+ PL spectrum of the upconversion luminescence optical temperature measurement material under 980 nm excitation. There are obvious peaks at 551 nm, 669 nm, and 762 nm. The emission peak at 551 nm is due to the 3+ transition of Ho 5 F4, 5 S2- 5 I8 transition. The emission peak at 669 nm is due to the 3+ transition of Ho 5 F5- 5 I8 transition. The emission peak at 762 nm is due to the 3+ transition of Ho 5 F4,5 S2- 5 Transition of I7. Figure 6 For the ZnO:Yb 3+ / Ho 3+ Variable-temperature luminescence spectra of the upconversion luminescence optical temperature measurement material. As the temperature increases, the peak positions of the upconversion luminescence centered at 551 nm, 669 nm, and 762 nm do not change significantly, but the upconversion luminescence intensity decreases with increasing temperature. Among them, the change in the upconversion luminescence intensity centered at 551 nm is more obvious. Figure 7 For the ZnO:Yb 3+ / Ho 3+ Experimental and fitted data spectra of the fluorescence intensity ratio of the upconversion luminescence optical temperature measurement material. As shown in the figure, in the range of 293 - 473 K, using the fluorescence intensity ratio of the non-thermally coupled energy levels Ho 3+ F5- 5 I8 and 5 F4, 5 S2- 5 I8, that is, the fluorescence intensity ratio FIR of the emission peak at 669 nm and the emission peak at 551 nm has a quantitative relationship with the temperature T. The fitted equation is: 5 ... . Figure 8 The relative temperature sensitivity image of the ZnO:Yb 3+ / Ho 3+ upconversion luminescence optical temperature measurement material has a maximum value of 2.27% K at 298 K -1 . Table 1 shows the comparison of the relative temperature sensitivities of the material ZnO:Yb 3+ / Ho 3+ of the present invention and other materials doped with Yb 3+ / Ho 3+ . It can be seen that the relative temperature sensitivity of the ZnO:Yb 3+ / Ho 3+ optical temperature measurement material prepared by the present invention is higher than that of most other materials doped with Yb 3+ / Ho 3+ optical temperature measurement materials.

[0023] Table 1. Comparison table of relative temperature sensitivities of the material ZnO:Yb 3+ / Ho 3+ of the present invention and other materials doped with Yb 3+ / Ho 3+ relative temperature sensitivity Example 2 As Figures 9 - 15 shown, in this example, ZnO:Yb was prepared 3+ / Er 3+ Upconversion luminescence optical temperature - measuring material. The material preparation process is as follows: Mix ZnO powder with Yb2O3 and Er2O3 powders in a ratio of 100:1:0.5 evenly, then put them into a tablet - pressing mold and press them into an ingot 4 with a diameter of 1.8 cm and a height of 2 cm. The obtained ingot 4 is placed in a graphite crucible 5 located in the reaction chamber of a direct - current arc - discharge device, and the tungsten - rod cathode 3 is fixed at a certain distance above the reaction raw material 4; after pumping the reaction chamber 1 to vacuum, fill the reaction chamber 1 with 50 kPa of oxygen as the reaction gas; turn on the circulating water device and pass cooling water from the copper base 6 and the condensation wall 2; adjust the height of the copper base 6 to make the graphite crucible 5 contact with the tungsten rod 3 and then pull apart immediately to start arc discharge. During the discharge process, keep the voltage at 15 V, the current at 50 A, and react for 40 s. Collect ZnO:Yb 3+ / Er 3+ Upconversion luminescence optical temperature - measuring nanomaterial. Figure 9 For the ZnO:Yb 3+ / Er 3+ XRD image of the upconversion luminescence optical temperature - measuring material. It can be seen from the figure that the diffraction peaks of the material belong to hexagonal wurtzite zinc oxide, Figure 10 For the ZnO:Yb 3+ / Er 3+ EDS energy spectrum of the upconversion luminescence optical temperature - measuring material. According to the quantitative analysis of the EDS energy spectrum, the atomic ratio of Zn:O:Yb:Er is approximately 47.22:46.47:4.33:0.81, Figure 11 For the ZnO:Yb 3+ / Er 3+ SEM image of the upconversion luminescence optical temperature - measuring material. It can be seen from the figure that the sample presents a hierarchical coral - like nanostructure, the length of the nanorods is 2 - 5 μm, and the diameter is 100 - 500 nm. Figure 12 For the ZnO:Yb 3+ / Er 3+ PL spectrogram of the upconversion luminescence optical temperature - measuring material under the excitation of 980 nm. The spectrum shows green emission bands at 525 nm and 564 nm, and a main red emission band at 662 nm. The emission spectrum extends to 800 nm. The emission peak at 525 nm is due to the 3+ transition of Er 2 H 11 / 2 - 4 I 15 / 2 transition, and the emission peak at 564 nm is due to the 3+ ion 4 S 11 / 2 - 4 I 15 / 2transition, and the emission peak at 662 nm is due to Er 3+ ions 4 F 9 / 2 - 4 I 15 / 2 transition. Figure 13 is the variable-temperature luminescence spectrum of the ZnO:Yb 3+ / Er 3+ upconversion luminescence optical temperature sensing material. As the temperature increases, the peak positions of the upconversion luminescence centered at 525 nm, 564 nm, and 662 nm do not change significantly, but the upconversion luminescence intensity decreases with increasing temperature. Figure 14 is the fluorescence intensity ratio experimental and fitting data spectra of the ZnO:Yb 3+ / Er 3+ upconversion luminescence optical temperature sensing material. As shown in the figure, in the range of 298 - 558 K, using the 662 nm emission peak and 677 nm emission peak of the 3+ F 4 - 9 / 2 I 4 energy level of Er 15 / 2 luminescence intensity ratio is in agreement with the fitting curve, and the fitted equation is: . Figure 15 is the relative temperature sensitivity diagram of the ZnO:Yb 3+ / Er 3+ upconversion luminescence optical temperature sensing material, with a maximum value of 2.71% K at 298 K -1 . Table 2 is the comparison table of the relative temperature sensitivity of the material ZnO:Yb 3+ / Er 3+ of the present invention and other materials doped with Yb 3+ / Er 3+ . It can be seen that the relative temperature sensitivity of the ZnO:Yb 3+ / Er 3+ optical temperature sensing material prepared by the present invention is higher than that of most other materials doped with Yb 3+ / Er 3+ optical temperature sensing materials.

[0024] Table 2. Comparison table of relative temperature sensitivity of the material ZnO:Yb 3+ / Er 3+ of the present invention and other materials doped with Yb 3+ / Er 3+ relative temperature sensitivity Example 3 As Figures 15 - 22 shown, in this example, ZnO:Yb 3+ / Nd3+ Upconversion luminescence optical temperature sensing material. The material preparation process is as follows: Mix ZnO powder with Yb2O3 and Nd2O3 powders in a ratio of 100:1:0.04, and then put the mixture into a tablet press mold to press into an ingot 4 with a diameter of 1.8 cm and a height of 2 cm. Place the obtained ingot 4 in a graphite crucible 5 located in the reaction chamber of a DC arc discharge device, and fix the tungsten rod cathode 3 at a certain distance above the reaction raw material 4. After evacuating the reaction chamber 1 to vacuum, fill the reaction chamber 1 with 55 kPa of oxygen as the reaction gas. Turn on the circulating water device and introduce cooling water from the copper seat 6 and the condensation wall 2. Adjust the height of the copper seat 6 to make the graphite crucible 5 contact the tungsten rod 3 and then pull apart immediately to start the arc discharge. During the discharge process, maintain the voltage at 10 V and the current at 65 A for 50 s. Collect ZnO:Yb 3+ / Nd 3+ Upconversion luminescence optical temperature sensing nanomaterial. Figure 16 For the ZnO:Yb 3+ / Nd 3+ XRD image of the upconversion luminescence optical temperature sensing material. It can be seen from the figure that the diffraction peaks of the material belong to hexagonal wurtzite structure zinc oxide. Figure 17 For the ZnO:Yb 3+ / Nd 3+ EDS spectrum of the upconversion luminescence optical temperature sensing material. According to the quantitative analysis of the EDS spectrum, the atomic ratio of Zn:O:Yb:Nd is approximately 41.99:44.02:2.47:0.84. Figure 18 For the ZnO:Yb 3+ / Nd 3+ SEM image of the upconversion luminescence optical temperature sensing material. It can be seen from the figure that the sample presents a hierarchical coral-like nanostructure, with the length of the nanorods being 2 - 5 μm and the diameter being 100 - 500 nm. Figure 19 For the ZnO:Yb 3+ / Nd 3+ PL spectrum of the upconversion luminescence optical temperature sensing material under the excitation of 980 nm. The emission spectrum shows a green emission band at 539 nm, an orange emission band at 601 nm, a red emission band at 660 nm, and near-infrared at 755 nm and 806 nm. The appearance of the new visible light emission band and the enhancement of the near-infrared luminescence intensity indicate that there is an effective electron transfer 3+ between Nd 3+ and Yb 3+ ions 2 G 9 / 2 , 4 G 7 / 2 - 4 I9 / 2 The electronic transition corresponding to Nd at 601 nm 3+ of the ion 2 G 9 / 2 , 4 G 7 / 2 - 4 I 11 / 2 The electronic transition corresponding to Nd at 660 nm 3+ of the ion 2 G 9 / 2 , 4 G 7 / 2 - 4 I 13 / 2 The electronic transition. The near-infrared 755 nm and 806 nm are due to 2 S 3 / 2 , 4 F 7 / 2 - 4 I 9 / 2 and 2 H 9 / 2 , 4 F 5 / 2 - 4 I 9 / 2 energy level transitions. Figure 20 This is the variable-temperature luminescence spectrum of the ZnO:Yb 3+ / Nd 3+ upconversion luminescence optical temperature measurement material. As the temperature increases, the positions of the upconversion luminescence peaks at 539 nm, 601 nm, and 660 nm do not change significantly, but the luminescence intensity decreases with increasing temperature, while the near-infrared luminescence intensity at 755 nm and 806 nm increases with increasing temperature. Figure 21 This is the fluorescence intensity ratio experimental and fitting data spectra of the ZnO:Yb 3+ / Nd 3+ upconversion luminescence optical temperature measurement material. As shown in the figure, in the range of 298 - 478 K, using the Nd 3+ non-thermally coupled energy levels 2 H 9 / 2 , 4 F 5 / 2 - 4 I 9 / 2 and 2 G 9 / 2 , 4 G 7 / 2 - 4 I 11 / 2 fluorescence intensity ratio, that is, the fluorescence intensity ratio FIR of the emission peak at 806 nm and the emission peak at 601 nm has a quantitative relationship with the temperature T, and the fitted equation is: . Figure 22 This is the ZnO:Yb3+ / Nd 3+ The relative temperature sensitivity image of the upconversion luminescence optical temperature measurement material has a maximum value of 3.41% K at 298 K -1 Table 3 shows the material ZnO:Yb of the present invention 3+ / Nd 3+ and other materials doped with Yb 3+ / Nd 3+ The comparison table of relative temperature sensitivities shows that the ZnO:Yb 3+ / Nd 3+ optical temperature measurement material prepared by the present invention has a relative temperature sensitivity higher than that of most other materials doped with Yb 3+ / Nd 3+ optical temperature measurement materials.

[0025] Table 3. The material ZnO:Yb of the present invention 3+ / Nd 3+ and other materials doped with Yb 3+ / Nd 3+ Comparison table of relative temperature sensitivities The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. ZnO-based upconversion luminescence optical temperature measurement nanomaterial, characterized in that: The chemical composition is ZnO: 1 mol% Yb 3 + , x mol% RE 3+ , where RE 3+ For Ho 3+ or 3+ or Nd 3+ ;x=0.04~0.

5.

2. The ZnO-based upconversion luminescence optical temperature measurement nanomaterial according to claim 1, characterized in that: The material is formed into a coral shape by self-assembly of nanorods, the top of the nanorods is in the shape of a hexagonal pyramid, the length of the nanorods is 2-5 μm, and the diameter is 100-500 nm.

3. ZnO: Yb according to claim 1 3+ / Ho 3+ Thermometry nanomaterials, characterized by: Using Ho 3+ The non-thermal coupling level 5 F4, 5 S2- 5 I8 and 5 F5- 5 Up-conversion luminescence intensity ratio of I8 It has a quantitative relationship with temperature T: . Among them I 669 for 5 F5- 5 I8 energy level transition (551 nm) upconversion luminescence intensity, I 551 for 5 F4, 5 S2- 5 I8 energy level transition (551 nm) upconversion luminescence intensity, A, B and C represent constants, T represents absolute temperature, and the fitting equation is: .

4. The ZnO-based upconversion luminescence optical temperature measurement nanomaterial according to claim 3, characterized in that: Relative temperature sensitivity of the material 2.27% K at 298 K -1 .

5. The ZnO-based upconversion luminescence optical temperature measurement nanomaterial according to claim 1, characterized in that: The RE 3+ For Er 3+ , using Er 3+ of 4 F 9 / 2 - 4 I 15 / 2 The upconversion luminescence intensity ratio of the 622 nm luminescence peak and the 677 nm luminescence peak of the energy level It has a quantitative relationship with temperature T: . Among them I 677 for 4 F 9 / 2 - 4 I 15 / 2 Energy level transition (677 nm) upconversion luminescence intensity, I 622 for 4 F 9 / 2 - 4 I 15 / 2 The up-conversion luminescence intensity of energy level transition (622 nm), A, B and C represent constants, T represents absolute temperature, and the fitting equation is: .

6. The ZnO-based upconversion luminescence optical temperature measurement nanomaterial according to claim 5, characterized in that: Relative temperature sensitivity of the material 2.71% K at 298 K -1 .

7. The ZnO-based upconversion luminescence optical temperature measurement nanomaterial according to claim 1, characterized in that: The RE 3+ Nd 3+ , using Nd 3+ The non-thermal coupling level 2 G 9 / 2 , 4 G 7 / 2 - 4 I 11 / 2 and 2 H 9 / 2 , 4 F 5 / 2 - 4 I 9 / 2 The fluorescence intensity ratio It has a quantitative relationship with temperature T: . Among them I 806 for 2 H 9 / 2 , 4 F 5 / 2 - 4 I 9 / 2 Energy level transition (806nm) upconversion luminescence intensity, I 601 for 2 G 9 / 2 , 4 G 7 / 2 - 4 I 11 / 2 Energy level transition (601 nm) upconversion luminescence intensity, A, B and C represent constants, T represents absolute temperature. The fitted equation is: .

8. The ZnO-based upconversion luminescence optical temperature measurement nanomaterial according to claim 7, characterized in that: Relative temperature sensitivity of the material 3.41% K at 298 K -1 .

9. The method for preparing the ZnO-based upconversion luminescent optical temperature measuring nanomaterial according to any one of claims 1 to 8, characterized in that: The method includes: Mix ZnO powder, Yb2O3 powder and RE2O3 powder in a molar ratio of ZnO: Yb2O3: RE2O3 = 100:1: 0.04-0.5, place in a mold and press into blocks; The mixed powder block is placed in a graphite crucible anode located in a reaction chamber of a DC arc discharge device, and the reaction chamber is evacuated and filled with gas; Discharge treatment is performed, the gas pressure of the discharge gas is 50~60 kPa, the voltage range is 10~20 V, the current is 50~80 A, and the reaction time is 40~60 s; Conversion luminescent optical thermometry nanomaterials on ZnO-based surfaces collected by condensation wall.

10. The method for preparing the ZnO-based upconversion luminescence optical temperature measurement nanomaterial according to claim 9, characterized in that: The RE2O3 is Ho2O3 or Er2O3 or Nd2O3.

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