Near-infrared luminescent material flexible fluorescent film and chemical reagent identification and temperature measurement device

Abstract

The invention discloses a near-infrared luminescent material flexible fluorescent film and a chemical reagent identification and temperature measurement device. The near-infrared luminescent material comprises an inorganic compound, the chemical composition formula of the inorganic compound is Y2-x-yMgTiO6: xNd < 3 + > / yEr < 3 + >, x is greater than or equal to 0 and less than or equal to 10%, and y is greater than or equal to 0 and less than or equal to 10%. The near-infrared light-emitting material has a plurality of emission peaks, the wavelengths of the emission peaks are respectively about 1375 nm and 1551 nm, the near-infrared light-emitting material can be excited by low-energy near-infrared light, and the chemical stability and the thermal stability are good. The intensity ratio of emission peaks at 1375 nm and 1551 nm during temperature change can have specific response to temperature change, and the fluorescent probe has the potential for fluorescent temperature measurement. The method comprises the following steps: mixing an organic matter A and an organic matter B which are one or two of organic silica gel, epoxy resin, polydimethylsiloxane, an optical pouring sealant and an ultraviolet curing adhesive; due to the fact that functional groups of different chemical reagents absorb different spectrums, chemical reagent recognition can be achieved by testing the spectrums.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of luminescent materials, and particularly relates to a near-infrared luminescent material flexible fluorescent film and a chemical reagent identification and temperature measuring device. BACKGROUND

[0002] Non-invasive detection technology has attracted extensive attention and important applications in industrial process monitoring, biomedical diagnosis, food quality analysis and other fields due to its characteristics of not needing to destroy the detected object or tissue. The core of the technology is to obtain internal information by interpreting the interaction between the detection signal (such as electromagnetic wave) and the target object. Among many detection signals, electromagnetic wave, especially near-infrared (NIR) light, is considered as an ideal medium for realizing non-invasive detection due to its strong anti-visual interference ability, good penetration into biological tissue, and sensitive response to the characteristic absorption of specific chemical bonds (such as O─H, C─H, N─H) in organic matter.

[0003] The near-infrared spectral region is usually divided into NIR-I (700-1000 nm) and NIR-II (1000-1700 nm). Among them, NIR-II luminescence has a deeper penetration depth in biological tissue and weaker tissue autofluorescence interference, showing great application potential in the field of biological sensing. At present, the light sources for realizing NIR-II luminescence mainly include incandescent lamps, halogen lamps and phosphor converted light emitting diodes (pc-LED (Wang Y, Liu G, Xia Z. NIR-II luminescence in Cr 4+ activated CaYGaO4 toward non-invasive temperature sensing and composition detection[J]. Laser&Photonics Reviews, 2024, 18(1): 2300717.))。In contrast, pc-LED light sources based on fluorescent powder conversion have the advantages of compact structure, high efficiency and low cost, and their performance depends on high-efficiency NIR-II fluorescent materials.

[0004] Among the many near-infrared luminescent centers, trivalent rare earth ions Er 3+ and Nd 3+ are favored due to their unique energy level structure and excellent luminescent properties. Er 3+ ions can produce characteristic emissions in the NIR-II region (such as ~1550 nm) under excitation by 808 nm or 980 nm laser, and this wavelength band has low environmental background, which is very suitable for temperature sensing under ambient light. Nd 3+Ions can be efficiently excited around 808 nm and produce multiple sharp emission peaks in the NIR-I and NIR-II regions (such as ~1060 nm, ~1330 nm), and their emission spectra can effectively cover the characteristic absorption bands of various functional groups. More importantly, the multi-peak emission characteristics of Er 3+ and Nd 3+ ions perfectly meet the requirements of the fluorescence intensity ratio (FIR) temperature measurement technology, which measures the ratio of the emission peak intensities of two non-thermal coupled energy levels to invert the temperature, has the advantages of strong anti-interference ability and high precision, and provides an ideal solution for realizing high-sensitivity, non-contact temperature sensing (Song E, Chen M, Chen Z, et al. Mn 2+ -activated dual-wavelength emitting materials toward wearable optical fibretemperature sensor[J]. Nature Communications, 2022, 13(1): 2166.)。

[0005] Although Er 3+ and Nd 3+ doped materials have great potential in optical sensing, further integration and device of them, especially the preparation of flexible thin films and the use of dual-function sensing devices for simultaneous sensing of multiple physical and chemical parameters (such as temperature and concentration of specific chemical reagents) still face challenges. It is of great significance to develop a flexible thin film integrated with high-efficiency Er 3+ / Nd 3+ co-doped near-infrared luminescent materials, and based on the changes in their luminescence characteristics (such as FIR), to realize non-invasive, real-time detection of the temperature and chemical composition concentration of the measured object, which is of great significance to promote the development of new generation of intelligent sensing technology.

[0006] Therefore, the present application aims to provide a flexible fluorescent thin film based on Er 3+ / Nd 3+ co-doped near-infrared luminescent materials and a temperature sensing and chemical reagent identification device to solve the problems of the prior art. SUMMARY

[0007] The purpose of the present application is to overcome the shortcomings of the prior art and provide a flexible fluorescent thin film of near-infrared luminescent materials and a temperature sensing and chemical reagent identification device. The preparation method is simple, easy to operate, low in equipment cost and pollution-free, and the chemical reagent identification and temperature sensing device can simultaneously realize real-time monitoring of the temperature and chemical composition concentration of the measured solution.

[0008] The purpose of the present application is achieved at least by one of the following technical solutions.

[0009] The present application provides a near-infrared luminescent material, which comprises an inorganic compound of the chemical formula Y 2-x-y MgTiO6: x Nd 3+ / y Er 3+ , wherein 0 ≤ x ≤ 10%, 0 ≤ y ≤ 10%.

[0010] Preferably, x is 1%.

[0011] Preferably, y is 2%.

[0012] Preferably, the luminescent material can generate near-infrared emission peaks with wavelengths of about 1375 nm and 1551 nm under 808 nm excitation; the emission wavelengths corresponding to the non-thermal coupled energy levels are 1375 nm and 1551 nm.

[0013] Preferably, the emission wavelengths of 1375 nm and 1551 nm show thermal quenching and anti-thermal quenching phenomena, respectively, when the temperature is increased, and the fluorescence intensity ratio shows a specific response to the change in temperature.

[0014] Preferably, the luminescent material has the chemical formula Y 1.97 MgTiO6:1%Nd 3+ / 2%Er 3+ , and the emission wavelength range thereof under 808 nm near-infrared light excitation is 1200-1800 nm, wherein the emission wavelengths corresponding to the non-thermal coupled energy levels are 1375 nm and 1551 nm.

[0015] Preferably, the absolute sensitivity of the luminescent material based on the fluorescence intensity ratio for temperature measurement is 6.89×10 -3 K -1 at 253 K, and the maximum relative sensitivity is obtained at 253 K, which is 0.547% K -1 .

[0016] The present application also provides a preparation method of the above-mentioned near-infrared luminescent material, which comprises the following steps: 1) raw materials are weighed according to the stoichiometric ratio of the chemical formula Y 2-x-y MgTiO6: x Nd 3+ / y Er 3+ , (in order to compensate for the loss of Y2O3 at high temperature, 30% excess Y2O3 is added), and the mixture is ground in an agate mortar for 30 minutes; 2) the mixture obtained in step 1) is placed in an alumina crucible and sintered in a muffle furnace; 3) The solid obtained in step 2) is ground into powder in a corundum mortar.

[0017] Preferably, in step 1), x is 1% and y is 2%.

[0018] Preferably, in step 2), the high-temperature sintering temperature is 1450℃, and the heating time is 6-8 h.

[0019] The application also provides a flexible fluorescent film, which is obtained by uniformly dispersing the above-mentioned near-infrared luminescent material in an organic polymer, pouring into a plastic mold, and taking out after heating and curing.

[0020] Preferably, the organic polymer comprises A and B, wherein A and B are one or two of organic silicone glue, epoxy resin, polydimethylsiloxane, optical potting glue, ultraviolet curing glue, and polymethyl methacrylate.

[0021] Preferably, the organic polymer is polydimethylsiloxane glue.

[0022] Further preferably, the near-infrared luminescent material is 0.4 g, the polydimethylsiloxane glue is 2 g, the heating and curing temperature is 100℃, and the curing time is 0.5-2 h.

[0023] The application also provides a chemical reagent identification and temperature measurement device, which comprises an excitation light source, an Edinburgh spectrometer, and the above-mentioned flexible fluorescent film.

[0024] Preferably, the chemical reagent solution comprises one or two of ammonia, acetone, methanol, ethanol, isopropanol, and deionized water.

[0025] Preferably, the excitation light source is 808 nm near-infrared light.

[0026] Compared with the prior art, the application has the following advantages: 1) The near-infrared luminescent material of the application has good thermal stability and does not pollute the environment.

[0027] 2) The near-infrared luminescent material of the present application can measure temperature by fluorescence intensity ratio at variable temperature, and the relative sensitivity can reach 0.547% K -1 .

[0028] 3) The preparation method of the present application is simple, easy to operate, low in equipment cost and pollution-free, and is suitable for universal popularization and use, and is expected to realize wide application in the field of flexible fluorescent film temperature measurement.

[0029] 4) The flexible fluorescent temperature sensing and chemical reagent identification device of the present application can monitor the temperature of the object in real time through the change of the fluorescence intensity ratio of the flexible film emitting near-infrared light, and is successfully applied to the identification and temperature measurement of chemical solutions.

[0030] 5) The flexible fluorescent temperature sensing device of the present application can monitor the temperature change of the chemical solution to be measured in real time, which is helpful to assist in realizing the thermal management of chemical solvents such as methanol, and avoiding damage caused by fire and explosion. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the X-ray diffraction pattern XRD of the near-infrared luminescent material prepared in examples 1, 2 and 3.

[0032] Figure 2 is the scanning electron microscope image SEM of the near-infrared luminescent material prepared in example 1.

[0033] Figure 3 is the fluorescence spectrum of the near-infrared luminescent material prepared in example 1.

[0034] Figure 4 is the emission spectrum of the near-infrared luminescent material prepared in example 1 at different temperatures.

[0035] Figure 5 is the schematic diagram of the relationship between the fluorescence intensity ratio of the non-thermal coupling energy level emission peak of the near-infrared luminescent material prepared in example 1 and the temperature.

[0036] Figure 6 is the temperature sensitivity diagram of the near-infrared luminescent material prepared in example 1.

[0037] Figure 7 is the flexible display diagram of the flexible fluorescent film prepared in example 4.

[0038] Figure 8 is the response diagram of the flexible fluorescent film prepared in example 4 to different chemical reagent solutions.

[0039] Figure 9 is the double-sensing response diagram of the flexible fluorescent film sensing device prepared in example 7 for measuring different concentrations and different temperatures of chemical reagent solutions. DETAILED DESCRIPTION

[0040] The present invention will be specifically described below with reference to the embodiments, but the implementation and protection scope of the present invention are not limited to the following embodiments.

[0041] Example 1 The chemical formula of the near-infrared phosphor in this embodiment is Y. 2-x-y MgTiO6: x Nd 3+ / y Er 3+ ,in x = 1%, y = 2%. According to the stoichiometric ratio of each element in the chemical formula (to compensate for the loss of Y₂O₃ at high temperature, an excess of 30% Y₂O₃ was added), accurately weigh 0.2190 g Y₂O₃, 0.0524 g MgO, 0.0799 g TiO₂, 0.0038 g Er₂O₃, and 0.0017 g Nd₂O₃. Then, grind the raw material powder in an agate mortar for 30 minutes, transfer it to an alumina crucible, cover it, and sinter it in an air-atmosphere high-temperature reactor at 1450℃ for 8 hours. After natural cooling, remove it and grind it again for about 10 minutes to obtain Y₂O₃. 1.97 MgTiO6:1%Nd 3+ / 2%Er 3+ Fluorescent powder.

[0042] The XRD, SEM, and fluorescence spectra of the near-infrared luminescent material prepared in Example 1 are shown below. Figure 1 ( Figure 1 The range of x and y values ​​has been expanded to include xrd). Figure 2 and Figure 3 As shown, from Figure 1 It can be seen from this that the phosphor is a single phase. Figure 2 It can be seen that the average particle size of the prepared near-infrared luminescent material is about a few micrometers. Figure 3 It can be seen that this phosphor can emit near-infrared light of 1200-1800 nm under 808 nm near-infrared light excitation, with the main emission peaks located around 1375 and 1551 nm. Figure 4 It can be seen that the emission peak position of the prepared near-infrared luminescent material remains unchanged at different temperatures, but the emission peak intensity changes with temperature.

[0043] Figure 5 This is a schematic diagram showing the relationship between the non-thermally coupled energy level emission peak intensity ratio of the near-infrared luminescent material prepared in Example 1 and temperature. The fluorescence intensity ratio (FIR) is fitted by an exponential function and can be deciphered as a temperature signal through a reference curve, which is the curve obtained by fitting the function relationship between FIR and temperature.

[0044] Figure 6 is a schematic plot of the temperature sensitivity of the near-infrared luminescent material prepared in Example 1, S a is the absolute sensitivity, S r is the relative sensitivity. According to Figure 6 It can be seen that the highest absolute sensitivity reaches 6.89 x 10 -3 K -1 at 253 K, and the highest relative sensitivity reaches 0.547% K -1 .

[0045] Example 2 The chemical composition formula of the near-infrared fluorescent powder of this example is Y 2-x-y MgTiO6: x Nd 3+ / y Er 3+ , wherein x = 10%, y = 0. According to the stoichiometric ratio of each element in the chemical formula, (in order to compensate for the loss of Y2O3 at high temperature, 30% excess Y2O3 is added), 0.2032 g of Y2O3, 0.0524 g of MgO, 0.0799 g of TiO2, and 0.0168 g of Nd2O3 are accurately weighed. Then the raw material powder is ground in an agate mortar for 30 minutes, transferred to an alumina crucible, and sintered in an air atmosphere high-temperature reaction furnace at 1450°C for 8 hours. After natural cooling, it is taken out and ground again for about 10 minutes to obtain Y 1.9 MgTiO6: 10%Nd 3++ fluorescent powder.

[0046] Example 3 The chemical composition formula of the near-infrared fluorescent powder of this example is Y 2-x-y MgTiO6: x Nd 3+ / y Er 3+ , wherein x = 0, y = 10%. According to the stoichiometric ratio of each element in the chemical formula, (in order to compensate for the loss of Y2O3 at high temperature, 30% excess Y2O3 is added), 0.2032 g of Y2O3, 0.0524 g of MgO, 0.0799 g of TiO2, and 0.0191 g of Er2O3 are accurately weighed. Then the raw material powder is ground in an agate mortar for 30 minutes, transferred to an alumina crucible, and sintered in an air atmosphere high-temperature reaction furnace at 1450°C for 8 hours. After natural cooling, it is taken out and ground again for about 10 minutes to obtain Y 1.9 MgTiO6: 10%Er 3+ fluorescent powder.

[0047] Example 4 A flexible fluorescent film capable of temperature sensing. The flexible fluorescent film of the present application is prepared according to the following method. 0.4 g of near-infrared fluorescent powder is uniformly dispersed in 2 g of polydimethylsiloxane glue, poured into a plastic mold, vacuumed for 10 min, and then taken out after curing at 80°C for 2 hours to obtain the flexible fluorescent film. The near-infrared fluorescent powder is the near-infrared fluorescent powder prepared in Example 1 above, and its chemical composition formula is Y 1.97 MgTiO6: 1% Nd 3+ / 2% Er 3+ .

[0048] Figure 7 is a flexible display diagram of the flexible fluorescent film prepared in Example 4, and it can be seen that the film has good flexibility and can be bent at will. Figure 8 is a response diagram of the flexible fluorescent film prepared in Example 4 to different chemical reagent solutions, which reflects the chemical reagent recognition property of the flexible fluorescent film.

[0049] Example 5 A flexible fluorescent film capable of temperature sensing. The flexible fluorescent film of the present application is prepared according to the following method. 0.4 g of near-infrared fluorescent powder is uniformly dispersed in 2 g of polydimethylsiloxane glue, poured into a plastic mold, vacuumed for 10 min, and then taken out after curing at 60°C for 4 hours to obtain the flexible fluorescent film. The near-infrared fluorescent powder is the near-infrared fluorescent powder prepared in Example 1 above, and its chemical composition formula is Y 1.97 MgTiO6: 1% Nd 3+ / 2% Er 3+ .

[0050] Example 6 A flexible fluorescent film capable of temperature sensing. The flexible fluorescent film of the present application is prepared according to the following method. 0.4 g of near-infrared fluorescent powder is uniformly dispersed in 2 g of polydimethylsiloxane glue, poured into a plastic mold, vacuumed for 10 min, and then taken out after curing at 150°C for 0.5 hours to obtain the flexible fluorescent film. The near-infrared fluorescent powder is the near-infrared fluorescent powder prepared in Example 1 above, and its chemical composition formula is Y 1.97 MgTiO6: 1% Nd 3+ / 2% Er 3+ .

[0051] Example 7 A device for temperature sensing and chemical reagent recognition of a flexible fluorescent film. It includes an excitation light source, an Edinburgh spectrometer, a chemical reagent solution (a mixed solution of methanol and deionized water), a temperature-variable table, a glass culture dish, and a flexible fluorescent film prepared in Example 4; The excitation light source directly irradiates the flexible fluorescent film, the excited near-infrared light is obtained by the Edinburgh spectrometer, the FIR is calculated, and the temperature information is converted according to the calibration curve. The flexible fluorescent film can absorb the light emitted by the near-infrared excitation light source and release near-infrared light, and the intensity ratio of the emission peaks of two different wavelengths changes specifically when the temperature changes. The flexible fluorescent film is placed in a glass dish containing a chemical reagent solution, and the glass dish is placed on a temperature changing table.

[0052] The real-time monitoring of temperature and (methanol and deionized water mixed solution) concentration of the sensing device obtained in application example 7 in a temperature increasing process is as follows Figure 9 As can be seen from the figure, the device can well perform fluorescence temperature measurement and effectively distinguish different solution concentrations, and is expected to be applied to the thermal management of methanol and other chemical solvents.

[0053] In summary, compared with the prior art, the present application has the following advantages: 1) The near-infrared luminescent material of the present application is thermally stable and has no environmental pollution. The emission peak intensity ratio has a specific response to temperature under low-energy near-infrared light excitation, which can be fitted by a function.

[0054] 2) The near-infrared luminescent material of the present application can measure temperature by fluorescence intensity ratio when the temperature changes, and the relative sensitivity can reach 0.547% K -1 .

[0055] 3) The preparation method of the present application is simple, easy to operate, low in equipment cost and pollution-free, and is suitable for popularization and use; it is expected to be widely used in the field of flexible fluorescent film temperature measurement.

[0056] 4) The chemical reagent recognition device of the present application can monitor the temperature of the object in real time through the change of the fluorescence intensity ratio of the flexible film emitting near-infrared light, and is successfully applied to the identification and temperature measurement of chemical solutions.

[0057] 5) The flexible fluorescent temperature sensing device of the present application can monitor the temperature change of the chemical solution to be measured in real time, which is helpful to assist in realizing the thermal management of methanol and other chemical solvents, and avoiding damage caused by fire and explosion.

[0058] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application is included in the protection scope of the present application.

Claims

1. A near-infrared luminescent material, characterized in that, Includes chemical formula Y 2-x-y MgTiO6: x Nd 3+ / y Er 3+ Inorganic compounds, where 0 ≤ x ≤ 10%, 0 ≤ y ≤ 10%.

2. The near-infrared luminescent material according to claim 1, characterized in that, The near-infrared luminescent material can generate near-infrared emission peaks with wavelengths of approximately 1375 nm and 1551 nm under 808 nm excitation; the emission wavelengths corresponding to the non-thermally coupled energy levels are 1375 nm and 1551 nm.

3. The near-infrared luminescent material according to claim 2, characterized in that, The emission wavelengths of 1375 nm and 1551 nm exhibit thermal quenching and antithermal quenching phenomena, respectively, upon heating, and their fluorescence intensity shows a specific response to temperature changes.

4. The near-infrared luminescent material according to claim 1, characterized in that, The near-infrared luminescent material can be thermometric by fluorescence intensity ratio.

5. A method for preparing a near-infrared luminescent material as described in any one of claims 1-4, comprising the following steps: 1) According to the general chemical formula Y 2-x-y MgTiO6: x Nd 3+ / y Er 3+ The raw materials were weighed according to the stoichiometric ratio and ground in an agate mortar. 2) Place the mixture obtained in step 1) into an alumina crucible and sinter it in a muffle furnace; 3) Grind the solid obtained in step 2) into powder in an agate mortar to obtain near-infrared luminescent material.

6. A flexible fluorescent film, characterized in that, The near-infrared luminescent material as described in any one of claims 1-4 is uniformly dispersed in an organic polymer, poured into a plastic template, heated and cured, and then removed.

7. A flexible fluorescent film according to claim 6, characterized in that, The organic polymers include A and B, wherein A and B are one or two of silicone, epoxy resin, polydimethylsiloxane, optical potting compound, UV curing adhesive, and polymethyl methacrylate.

8. The flexible fluorescent film according to claim 6, characterized in that, The heating and curing temperature is 60~150 degrees Celsius, and the curing time is 0.5~4 hours.

9. A chemical reagent identification and temperature measuring device, characterized in that, The invention includes an excitation light source, a spectrometer, and the flexible fluorescent film as described in any one of claims 6-8. The flexible fluorescent film is placed in air / different chemical reagent solutions. The flexible fluorescent film absorbs light emitted by the near-infrared excitation light source and emits near-infrared light. Due to the different spectral absorptions of functional groups, the spectra in different chemical reagent solutions exhibit specific changes, and the type of chemical reagent solution can be identified by the fluorescence intensity ratio of the spectra. The fluorescence intensity ratio undergoes specific changes with temperature variations, which can be deciphered as a temperature signal through a reference curve, enabling real-time, in-situ monitoring of the temperature of air / different chemical reagent solutions.

10. A chemical reagent identification and temperature measuring device according to claim 9, characterized in that, The chemical reagent solution includes, but is not limited to, one or two of ammonia, acetone, methanol, ethanol, isopropanol, and deionized water.

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