Quantum dot fluorescence lifetime fiber-optic temperature sensing system

Abstract

The application relates to the temperature sensing field and particularly provides a quantum dot fluorescent lifetime optical fiber temperature sensing system, which comprises an optical fiber circulator, the optical fiber circulator is connected with a light source, a light detector and one end of a sensing optical fiber, light emitted by the light source is incident on the sensing optical fiber through the optical fiber circulator, the light emitted by the sensing optical fiber enters the light detector through the optical fiber circulator, one end of the sensing optical fiber is connected with the optical fiber circulator, the other end of the sensing optical fiber is a detection end, a quantum dot is fixedly arranged on the end face of the detection end, a piezoelectric material layer is further arranged on the end face of the detection end, the piezoelectric material layer covers the quantum dot, the quantum dot is arranged in the piezoelectric material layer, and a thermal expansion layer is fixedly arranged on the side, away from the sensing optical fiber, of the piezoelectric material layer. The specific surface area of the molybdenum disulfide quantum dot is large, the molybdenum disulfide quantum dot is easily affected by temperature, the change of the fluorescent lifetime detected by the system is large under the condition that the temperature change amount is the same, and the detection sensitivity of the temperature sensing system is high.

Description

Technical Field

[0001] This application relates to the field of temperature sensing, and more specifically, to a quantum dot fluorescence lifetime fiber optic temperature sensing system. Background Technology

[0002] Temperature detection is generally achieved through temperature sensing devices. These devices convert changes in temperature into changes in other physical quantities, such as current, voltage, light intensity, wavelength, color, and shape. Since changes in temperature cause changes in these other physical quantities, and the temperature being measured is generally changing, the physical quantity output by the temperature sensing device must also change accordingly. If the measured temperature has changed, but the physical quantity output by the temperature sensing device remains unchanged or changes only slightly, meaning the change in the physical quantity does not keep pace with the change in the measured temperature, the detection result will be inaccurate. Therefore, the sensitivity of the temperature sensing device to temperature changes is crucial.

[0003] Temperature sensing devices based on optical principles have relatively high sensitivity. When a substance is excited by a laser beam, its molecules absorb energy and transition from the ground state to an excited state, then emit fluorescence in the form of radiative transitions back to the ground state. The time required for the fluorescence intensity of the molecule to drop to 1 / e of its maximum intensity after excitation is stopped is called the fluorescence lifetime, which is the energy level lifetime of free ions or ions in a crystal. It represents the average time a particle exists in the excited state, usually called the fluorescence lifetime of the excited state. Generally, the wavelength of fluorescence is longer than the wavelength of incident light, and the fluorescence lifetime, wavelength, and intensity are closely related to temperature and the surrounding medium. Existing temperature sensing devices based on optical principles include: fluorescence intensity type temperature sensing devices that detect temperature by light intensity; fluorescence intensity ratio type temperature sensing devices that detect temperature by light intensity ratio; and fluorescence lifetime type temperature sensing devices that detect temperature by detecting fluorescence decay time, i.e., fluorescence lifetime. Fluorescence intensity type temperature sensing devices directly detect the intensity of emitted fluorescence, which is easily affected by light source fluctuations during the detection process, requiring additional reference channels, making the system complex and costly. Fluorescence intensity ratio-based temperature sensors utilize ratios to avoid the influence of excitation light source intensity, resulting in relatively high accuracy. However, the light intensity reference channel complicates the circuit design and reduces accuracy. Fluorescence lifetime-based temperature sensors use the fluorescence lifetime of crystalline materials such as ruby, rare-earth-doped powder, and phosphor nanoparticles for temperature detection. However, they only consider the effect of temperature on fluorescence lifetime, which is related to multiple factors. Therefore, fluorescence lifetime-based temperature sensors that only consider temperature have low sensitivity.

[0004] In summary, existing temperature sensing devices have low detection sensitivity and cannot meet the requirements for high-sensitivity temperature detection. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a quantum dot fluorescence lifetime fiber optic temperature sensing system, thereby solving the problem that existing temperature sensing devices have low detection sensitivity and cannot meet the requirements for high-sensitivity temperature detection.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This application provides a quantum dot fluorescence lifetime fiber optic temperature sensing system. The system includes a fiber optic circulator, which is connected to a light source, a photodetector, and one end of a sensing fiber. Light emitted from the light source passes through the fiber optic circulator and enters the sensing fiber. Light emitted from the sensing fiber passes through the fiber optic circulator and enters the photodetector. One end of the sensing fiber is connected to the fiber optic circulator, and the other end of the sensing fiber is a detection end. A quantum dot is fixedly disposed on the end face of the detection end, and a piezoelectric material layer is also disposed on the end face of the detection end. The piezoelectric material layer covers the quantum dot, and the quantum dot is disposed inside the piezoelectric material layer. A thermal expansion layer is fixedly disposed on the side of the piezoelectric material layer away from the sensing fiber.

[0008] Furthermore, the quantum dots are molybdenum disulfide quantum dots, with a size of less than 5 nm and a size difference of less than or equal to 2 nm.

[0009] Furthermore, molybdenum disulfide quantum dots are prepared according to the following steps: first, (NH4)6Mo7O 24 4H₂O was dissolved in deionized water, and the pH was adjusted to 6.5 using ammonia solution. Glutathione was added to the pH 6.5 solution, and then added to deionized water. The mixture was stirred until completely dissolved to obtain a solution sample. The solution sample was placed in a high-pressure reactor for hydrothermal reaction at a temperature of 190℃-210℃ for 22-26 hours. After the hydrothermal reaction, the solution was allowed to cool naturally to room temperature. The solution obtained from the hydrothermal reaction was filtered, centrifuged, and dialyzed to finally obtain molybdenum disulfide quantum dots.

[0010] Furthermore, (NH4)6Mo7O 24 The mass ratio of 4H2O to glutathione was 46.8:254, the mass fraction of ammonia was 10%, the centrifugation speed was greater than 8000 r / min, and the time was 20 min.

[0011] Furthermore, the diameter of the sensing end of the sensing fiber closer to the piezoelectric material layer is larger than the diameter of the side farther away from the piezoelectric material layer.

[0012] Furthermore, the sensing fiber is composed of a central ray and multiple edge fibers coaxially distributed around the central ray.

[0013] Furthermore, the center wavelength of the light source is 400nm-450nm.

[0014] Furthermore, the sensing fiber is a single-mode silica fiber or a multimode silica fiber.

[0015] Furthermore, the piezoelectric material layer is made of one of the following: polyvinylidene fluoride, piezoelectric ceramics, lead magnesium niobate, barium titanate, lead zirconate titanate, lead metaniobate, lithium lead barium niobate, quartz crystal, lithium gallium oxide, lithium germanate, titanium germanate, lithium niobate, and lithium tantalate.

[0016] Furthermore, the material of the thermal expansion layer is one of the following: metallic chromium, vermiculite, polyvinylidene chloride, vinyl acetate copolymer, or epoxy resin.

[0017] Compared with existing technologies, the advantages of this invention are as follows: The temperature sensing system of this invention uses molybdenum disulfide quantum dots as the sensing material. Quantum dots have a large specific surface area and are more easily affected by temperature, thus resulting in higher detection sensitivity. Furthermore, the detected fluorescence lifetime is not only related to temperature but also to the surrounding environment. Changes in the surrounding environment, through thermal expansion materials, also depend on changes in the measured temperature. Therefore, under the same change in measured temperature, the system of this application detects a larger change in fluorescence lifetime, resulting in higher detection sensitivity. Attached Figure Description

[0018] Figure 1 A schematic diagram of a quantum dot fluorescence lifetime fiber optic temperature sensing system provided by the present invention;

[0019] Figure 2 TEM image of molybdenum disulfide quantum dots prepared in a quantum dot fluorescence lifetime fiber optic temperature sensing system provided by the present invention;

[0020] Figure 3 The excitation spectrum (solid line) and emission spectrum (dashed line) of molybdenum disulfide quantum dots in a quantum dot fluorescence lifetime fiber optic temperature sensing system provided by the present invention;

[0021] Figure 4 The present invention provides a structure for the sensing end face of a sensing fiber in a quantum dot fluorescence lifetime fiber optic temperature sensing system.

[0022] Figure 5 This invention provides an alternative structure for the sensing fiber end face in a quantum dot fluorescence lifetime fiber optic temperature sensing system.

[0023] Figure 6 This is a schematic diagram of another sensing fiber in a quantum dot fluorescence lifetime fiber optic temperature sensing system provided by the present invention.

[0024] Icons: 1-Fiber optic circulator; 2-Sensing fiber; 3-Quantum dot; 4-Piezoelectric material layer; 5-Thermal expansion layer. Detailed Implementation

[0025] To make the implementation process of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings.

[0026] This invention provides a quantum dot fluorescence lifetime fiber optic temperature sensing system, such as... Figure 1 As shown, the fiber optic temperature sensing system disclosed in this application includes a light source, a photodetector, a sensing fiber 2, a fiber optic circulator 1, quantum dots 3, a piezoelectric material layer 4, and a thermal expansion layer 5. The three ports of the fiber optic circulator 1 are respectively connected to the light source, the photodetector, and the sensing fiber 2. The light source is connected to the inlet of the fiber optic circulator 1, and the photodetector and the sensing fiber 2 are connected to the two outlets of the fiber optic circulator 1. Light emitted from the light source passes through the fiber optic circulator 1 and enters the sensing fiber 2. After acquiring sensing information at the other end of the sensing fiber 2, it enters the fiber optic circulator 1 again, and after entering the fiber optic circulator 1, it is transmitted out from one end of the photodetector and detected by the photodetector. One end of the sensing fiber 2 is connected to the fiber optic circulator 1, and the other end is the detection end. The detection end of the sensing fiber 2 is the end face of the sensing fiber 2, and quantum dots 3, which can be molybdenum disulfide quantum dots 3, are fixedly disposed on the sensing end face. A piezoelectric material layer 4 is disposed around the quantum dots 3, and the quantum dots 3 are embedded within the piezoelectric material layer 4, and the quantum dots 3 are in contact with the end face of the sensing fiber 2. A thermal expansion layer 5 is fixedly disposed on the side of the piezoelectric material layer 4 away from the sensing optical fiber 2, covering the piezoelectric material layer 4; the thermal expansion layer 5 is in direct contact with the environment under test. The sensing end of the sensing optical fiber 2 is located in the environment under test and is used to detect the temperature in the environment under test.

[0027] Quantum dots 3 are fixedly disposed on the sensing end face of the sensing fiber 2. The size of quantum dots 3 is less than 5 nm, preferably less than 3 nm, so that the quantum confinement effect is more obvious. The size of quantum dots 3 can be the same or different. Preferably, the size difference of quantum dots 3 is less than or equal to 2 nm, so that the corresponding excitation wavelength and fluorescence wavelength are close, superimposed, with greater intensity, easier detection, and more accurate detection of the corresponding fluorescence lifetime, thus resulting in higher accuracy of temperature detection. The distribution of quantum dots 3 can be uniform or non-uniform. Preferably, adjacent quantum dots 3 are closely arranged, so that the light emitted from the sensing fiber 2 can fully illuminate the surface of the quantum dots 3, and the utilization rate of the light field energy in the sensing fiber 2 is higher. The quantum dots 3 at the core of the sensing fiber 2 and the quantum dots 3 at the cladding have different functions. The quantum dots 3 at the core are mainly used to generate fluorescence upon excitation to achieve the purpose of temperature detection, while the quantum dots 3 at the cladding are mainly used to reflect the generated fluorescence, although a small number of quantum dots also generate fluorescence, contributing to temperature detection.

[0028] Molybdenum disulfide quantum dots 3 have a high specific surface area, a large number of unsaturated bonds, numerous dangling bonds and edge active sites, and high quantum efficiency. Under the influence of the quantum confinement effect, they exhibit strong photoluminescence, thus producing strong fluorescence upon excitation by excitation light. This makes the fluorescence easily detectable, leading to the determination of fluorescence lifetime, which enables the system of this invention to accurately detect temperature. The preparation of molybdenum disulfide quantum dots 3 is as follows: First, (NH4)6Mo7O 24 4H₂O was dissolved in deionized water, and the pH was adjusted to 6.5 using ammonia solution. Glutathione was added to the pH 6.5 solution, and then both were added to the deionized water. The mixture was stirred until completely dissolved to obtain a solution sample. The solution sample was placed in a high-pressure reactor for hydrothermal reaction at a temperature of 190℃-210℃, preferably 200℃. The hydrothermal reaction time was 22h-26h, preferably 24h. After the hydrothermal reaction, the solution was allowed to cool naturally to room temperature. The solution obtained from the hydrothermal reaction was filtered, centrifuged, and dialyzed to finally obtain molybdenum disulfide quantum dots 3. Filtration can be performed using a sand filter or other filter paper, with a pore size of 0.22 μm, to remove suspended particulate matter from the solution. After filtration, centrifugation is performed at a speed greater than 8000 r / min, preferably 10000 r / min, for 20 min. The supernatant is collected. The supernatant is placed in a dialysis bag for dialysis for more than 24 h. The molecular weight cutoff of the dialysis bag is 10000 u. Molybdenum disulfide quantum dots 3 are obtained after dialysis. (NH4)6Mo7O 24 The mass ratio of 4H₂O to glutathione was 46.8:254, and the mass fraction of ammonia was 10%. TEM images of the prepared molybdenum disulfide quantum dots 3 are shown below. Figure 2 As shown.

[0029] The piezoelectric material layer 4 is a piezoelectric material that provides a variable dielectric environment for molybdenum disulfide. Under stress and deformation, polarization occurs, generating opposite charges on opposite sides, causing a change in the polarity of the dielectric material surrounding the quantum dot 3 near one of the opposite sides. This change in dielectric polarity depends on the pressure applied to the piezoelectric material; the greater the pressure, the stronger the polarization, the more charge generated, and the greater the change in polarity of the dielectric material around the quantum dot 3. This change in dielectric polarity alters the electron motion process within the quantum dot 3, thus affecting the fluorescence lifetime of the quantum dot 3. The piezoelectric material in the piezoelectric material layer 4 can be one of the following: polyvinylidene fluoride, piezoelectric ceramics, lead magnesium niobate, barium titanate, lead zirconate titanate, lead metaniobate, lithium lead barium niobate, quartz crystal, lithium gallium oxide, lithium germanate, titanium germanate, lithium niobate, or lithium tantalate. It can be prepared using vapor deposition technology.

[0030] A thermal expansion layer 5 is fixedly disposed on the side of the piezoelectric material layer 4 away from the quantum dot 3, and covers the piezoelectric material layer 4. The material of the thermal expansion layer 5 is a thermally expanding material, specifically, it can be metallic chromium, vermiculite, polyvinylidene chloride, vinyl acetate copolymer, epoxy resin, etc. When the thermal expansion layer 5 comes into contact with the test environment, its volume changes and deforms when the test temperature changes, thereby generating stress on the piezoelectric material layer 4. Under the polarization effect, charge accumulates on the two opposite sides of the piezoelectric material layer 4. The quantum dot 3 is disposed near one of the opposite sides, thereby changing the polarity of the dielectric material around the quantum dot 3, and ultimately changing the lifetime of fluorescence generated by the quantum dot. When the material of the thermal expansion layer 5 is metallic chromium, in addition to the effect of thermal expansion and contraction, it can also reflect the generated fluorescence, allowing more fluorescence to enter the sensing optical fiber and be detected by the photodetector.

[0031] The sensing fiber 2 can be either a single-mode silica fiber or a multimode silica fiber, or it can consist of multiple single-mode or multiple multimode silica fibers. The sensing fiber 2 illuminates the quantum dot 3 with excitation light emitted from a light source. Electrons on the quantum dot 3 transition from the valence band to the conduction band, and then return from the excited state in the conduction band to the ground state, simultaneously emitting fluorescence. The emitted fluorescence is collected by the sensing fiber and ultimately received by a photodetector, yielding the fluorescence lifetime. The fluorescence lifetime emitted by the quantum dot 3 is closely related to the size of the quantum dot, the type of quantum dot 3, the arrangement of the quantum dot 3, and the polarity of the dielectric material surrounding the quantum dot 3. Once the system is determined, the fluorescence lifetime mainly depends on the polarity of the dielectric material surrounding the quantum dot 3. The polarity of the dielectric material is closely related to the force on the piezoelectric material layer 4, which in turn is closely related to the deformation of the thermal expansion layer 5. The degree of deformation of the thermal expansion layer 5 is closely related to the temperature being measured. Therefore, this application can obtain the temperature to be measured by detecting the fluorescence lifetime of quantum dot 3. The aforementioned dependencies are all strong, and the accuracy and sensitivity of temperature detection are both high. The excitation and emission spectra of the molybdenum disulfide quantum dots 3 prepared in this application are as follows: Figure 3 As shown, the center wavelength of the excitation light is 430 nm, and the center wavelength of the emitted fluorescence is 310 nm. This is not a limitation on the wavelength of the laser emitted by the light source, but merely an example. The photon energy of the laser emitted by the light source needs to be greater than the band gap of the molybdenum disulfide quantum dot 3, and the wavelength of the laser emitted by the light source should be less than 1800 nm. Preferably, the center wavelength of the laser is 400 nm-450 nm. To improve the signal-to-noise ratio, weak signal detection and processing techniques can be used, such as high-sensitivity detectors, amplification circuits, light source modulation, phase-locked loop technology, etc., to process the obtained signal. During fabrication, after the quantum dot 3 is set, the piezoelectric material layer 4 and the thermal expansion layer 5 can be sequentially deposited using a vacuum chamber electron beam evaporation coating apparatus.

[0032] Furthermore, the sensing end of the sensing fiber 2 is also equipped with noble metal particles, which are mixed with quantum dots. Noble metal particles are also arranged around the molybdenum disulfide quantum dot 3, with both particles positioned on the same plane and on the end face of the sensing end of the sensing fiber 2. The noble metal particles are made of gold or silver and have a size of 20nm-200nm. When light from the sensing fiber 2 shines on the surface of the noble metal particles, the particles generate a localized surface plasmon resonance effect, causing a large number of electrons to accumulate on their surface and forming a strong local electric field. This strong local electric field makes the electrons in the excited state near the quantum dot 3 more unstable, thus altering the fluorescence lifetime of the quantum dot 3. In other words, the strong electric field generated by the noble metal particles can change the rate of electron-hole recombination within the quantum dot, thereby affecting the fluorescence lifetime. On the other hand, the strong electric field generated on the surface of the noble metal particles increases the polarization intensity of the piezoelectric material, resulting in more polarization changes in the dielectric material surrounding the quantum dot 3, thus having a greater impact on the fluorescence lifetime. When the temperature to be measured changes, the force exerted by the thermal expansion layer 5 on the piezoelectric material layer 4 changes, thereby altering the polarization intensity of the piezoelectric material layer 4. The addition of noble metal particles makes the change in polarization intensity even greater, thus increasing the change in fluorescence lifetime. At the same time, it changes the electron-hole recombination rate, making the change in polarization intensity lead to a greater change in fluorescence lifetime. Therefore, the addition of noble metal particles significantly enhances the change in fluorescence lifetime caused by temperature changes, improving the sensitivity of temperature detection.

[0033] Furthermore, such as Figure 4 As shown, the sensing end of the sensing fiber 2 is not planar but curved, forming a concave structure inside the sensing fiber 2. This has several advantages. First, compared to a planar structure, the curved structure has a larger area, allowing for the placement of more quantum dots 3, resulting in more fluorescence and higher detection efficiency. Second, the core is closer to the interior of the sensing fiber 2, resulting in stronger excitation light intensity illuminating the quantum dots 3. Furthermore, at the boundary between the core and cladding, due to the different lengths, more evanescent waves leak, leading to stronger fluorescence from the quantum dots 3. Third, the curved surface allows for a larger divergence angle of the excitation light, enabling more quantum dots 3 to be illuminated, resulting in stronger fluorescence from more quantum dots and higher detection efficiency. Finally, the corresponding piezoelectric material layer 4 is a matching protrusion. The protruding curved surface makes the polarization near the quantum dots more uniform, resulting in more consistent changes in fluorescence lifetime for different quantum dots, making detection easier. Therefore, the detection sensitivity and accuracy of the system in this application are high.

[0034] Furthermore, the diameter of the sensing fiber at the sensing end of sensing fiber 2 is not uniform, such as... Figure 5As shown, the diameter is larger on the side closer to the piezoelectric material layer 4 and smaller on the side farther away from the piezoelectric material layer 4. This results in a larger sensing end area, allowing for the placement of more quantum dots 3, more thorough interaction between the excitation light and the quantum dots 3, and the excitation of stronger fluorescence. The larger area also facilitates fluorescence collection by the sensing fiber. The sensing end can be fabricated using reverse tapered fiber technology, where the fiber is melted and then compressed towards the center to increase its diameter; the desired portion is then cut off.

[0035] like Figure 6 As shown, the sensing fiber 2 can be composed of multiple fibers, including a central fiber and edge fibers coaxially distributed around the central fiber. The central fiber is mainly used to excite and generate fluorescence, while the edge fibers are mainly used to collect the generated fluorescence. The edge fibers can collect fluorescence from all directions, thus resulting in higher fluorescence collection efficiency and reducing the difficulty of fluorescence signal detection.

[0036] In application, the sensing end of the sensing fiber 2 is placed in the environment under test. The connections of the sensing fiber 2, light source, photodetector, and fiber optic circulator 1 are checked to ensure that light emitted from the light source enters the sensing fiber 2 through the fiber optic circulator 1, and light emitted from the sensing fiber 2 enters the photodetector through the fiber optic circulator 1. The light emitted from the light source illuminates the quantum dot 3 at the sensing end of the sensing fiber 2. Electrons within the quantum dot 3 transition from the ground state to an excited state, and then return from the excited state to the ground state, generating fluorescence. The lifetime of the emitted fluorescence is detected by the photodetector. The volume of the thermal expansion layer 5 at the sensing end changes with the temperature of the environment under test. This change in the volume of the thermal expansion layer 5 alters the force acting on the piezoelectric material layer 4. This change in the force acting on the piezoelectric material layer 4 causes a change in the internal polarization intensity, which in turn causes a change in the dielectric material surrounding the quantum dot 3, ultimately affecting the lifetime of the fluorescence emitted by the quantum dot 3. This application transforms the effect of temperature on fluorescence into the effect of the polarity of the surrounding dielectric material on fluorescence lifetime by using thermally expanding and piezoelectric materials. The latter has a stronger dependence and a greater impact. Therefore, the temperature detection sensitivity and accuracy of the system in this application are higher.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A quantum dot fluorescence lifetime fiber optic temperature sensing system, comprising a fiber optic circulator connected to a light source, a photodetector, and one end of a sensing fiber, wherein light emitted from the light source passes through the fiber optic circulator and enters the sensing fiber, and light emitted from the sensing fiber passes through the fiber optic circulator and enters the photodetector, characterized in that... One end of the sensing optical fiber is connected to the optical fiber circulator, and the other end of the sensing optical fiber is a detection end. A quantum dot is fixedly disposed on the end face of the detection end, and a piezoelectric material layer is also disposed on the end face of the detection end. The piezoelectric material layer covers the quantum dot, and the quantum dot is disposed inside the piezoelectric material layer. A thermal expansion layer is fixedly disposed on the side of the piezoelectric material layer away from the sensing optical fiber.

2. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 1, characterized in that, The quantum dots are molybdenum disulfide quantum dots, and the size of the quantum dots is less than 5 nm, with a size difference of less than or equal to 2 nm.

3. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 2, characterized in that, The molybdenum disulfide quantum dots were prepared according to the following steps: First, (NH4)6Mo7O 24 4H₂O was dissolved in deionized water, and the pH was adjusted to 6.5 using ammonia solution. Glutathione was added to the solution with a pH of 6.5, and then added to deionized water. The mixture was stirred until completely dissolved to obtain a solution sample. The solution sample was placed in a high-pressure reactor for hydrothermal reaction at a temperature of 190℃-210℃ for 22-26 hours. After the hydrothermal reaction, the solution was allowed to cool naturally to room temperature. The solution obtained from the hydrothermal reaction was filtered, centrifuged, and dialyzed to finally obtain the molybdenum disulfide quantum dots.

4. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 3, characterized in that, The (NH4)6Mo7O 24 The mass ratio of 4H2O to the glutathione is 46.8:254, the mass fraction of the ammonia is 10%, the centrifugation process is carried out at a speed greater than 8000 r / min for 20 min.

5. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 4, characterized in that, The diameter of the sensing end of the sensing optical fiber closer to the piezoelectric material layer is larger than the diameter of the side farther away from the piezoelectric material layer.

6. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 5, characterized in that, The sensing fiber is composed of a central fiber and multiple edge fibers coaxially distributed around the central fiber.

7. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 1, characterized in that, The center wavelength of the light source is 400nm-450nm.

8. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 1, characterized in that, The sensing fiber is a single-mode silica fiber or a multimode silica fiber.

9. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 1, characterized in that, The piezoelectric material layer is made of one of the following: polyvinylidene fluoride, piezoelectric ceramics, lead magnesium niobate, barium titanate, lead zirconate titanate, lead metaniobate, lithium lead barium niobate, quartz crystal, lithium gallium oxide, lithium germanate, titanium germanate, lithium niobate, and lithium tantalate.

10. The quantum dot fluorescence lifetime fiber optic temperature sensing system according to claim 1, characterized in that, The material of the thermal expansion layer is one of metallic chromium, vermiculite, polyvinylidene chloride, vinyl acetate copolymer, and epoxy resin.

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