Stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 fluorescent powder, and preparation method and application thereof

Abstract

The application relates to a stress and temperature dual-mode sensing Yb-Nd co-doped Sr3Sn2O7 fluorescent powder, a preparation method thereof and application, and belongs to the field of stress luminescence and up-conversion luminescence materials. The raw material of the stress and temperature dual-mode sensing Yb-Nd co-doped Sr3Sn2O7 fluorescent powder comprises a main component, a fluxing agent, a dopant, Yb 3+ and Nd 3+ sources: the stoichiometric ratio of each element is expressed as (1-x)(Sr 2.99‑y Sn2O7:0.01Nd 3+ ,yYb 3+ )-xLi; wherein x=0-0.4; y=0.001-0.01. The preparation method of the fluorescent powder adopts solid phase reduction reaction sintering, and after preparation, the fluorescent powder is integrated with medical bone cement, the dual stress and temperature sensing property of the fluorescent powder is utilized, and accurate and non-contact monitoring of the condition of a joint prosthesis is realized.

Description

Technical Field

[0001] This invention relates to a stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor, its preparation method and application, particularly its application in postoperative infection detection, and belongs to the field of stress luminescence and upconversion luminescence materials. Background Technology

[0002] Knee replacement surgery has been routinely performed for decades, and its number continues to grow worldwide, improving the quality of life for patients with knee osteoarthritis by reducing pain and improving long-term function. Despite the maturity of knee replacement surgery, postoperative infection monitoring remains a significant challenge due to its elusive complexity. Postoperative complications typically manifest as joint movement disorders and weight-bearing imbalances, often attributed to the inherent instability of the prosthesis components and wear of the polyethylene pad. This intricate interaction largely contributes to the necessity of subsequent replacement. Force measurements during knee replacement surgery help determine wear and cold flow of the polyethylene material, stress distribution at the prosthesis and prosthesis-bone interface, and stress transfer to the underlying bone. Simultaneously, postoperative infection, characterized by significant local swelling and elevated temperature, further complicates the recovery process. Therefore, accurate monitoring of stress and temperature within the artificial joint is crucial for proactively identifying irrational stress distributions and inflammation in affected areas.

[0003] However, current research lacks significant advancements in the simultaneous detection of stress and temperature in the near-infrared spectroscopy. Based on this, two feasible strategies have emerged. The first requires designing traditional sensing methods with complex architectural constraints, typically electronic sensors. These often require wired connections and current inputs, presenting challenges in terms of complex device architecture and miniaturization, which may limit their application in biological systems and generally lead to reduced fault tolerance. The second approach utilizes optical temperature or stress sensing techniques, leveraging widely developed up-conversion luminescent materials. This technology enables self-calibration and self-adjustment of fluorescence intensity ratios, thereby improving temperature sensing accuracy and lifetime. However, these methods often struggle to simultaneously incorporate the dual sensing properties of pressure and temperature, particularly in the biosensitive near-infrared band.

[0004] Stress-luminescent materials emit photons when subjected to mechanical stimuli such as pressure, bending, and torsion. Compared to traditional sensing techniques, stress-luminescent materials offer direct, reliable, and highly sensitive on / off modulation. This property stems from their unique characteristics, which facilitate miniaturization and real-time visualization of pressure. The pursuit of temperature-proportional materials, combined with their stress-sensing properties, holds the potential to effectively address the aforementioned challenges. Furthermore, these materials exhibit emission spectra spanning a wide wavelength range, extending from ultraviolet to visible and near-infrared light. This remarkable spectral diversity indicates their immense potential in various fields, including artificial electronic skin, stress sensing, optical information storage, and multimodal anti-counterfeiting.

[0005] Existing dual-mode sensors mainly fall into two categories. One is based on traditional electrically conductive structures, which offers high detection sensitivity and the ability to integrate multiple sensing modes. However, the large size required for battery use and complex structural design significantly limits its application in biological systems. Therefore, another approach has emerged: innovative design and rare-earth ion doping of phosphors for functional integration, enabling multi-mode sensing. Phosphors possess miniaturization and passive properties, offering unique advantages for in vivo applications. Consequently, exploring novel near-infrared dual-mode sensing phosphors has become a research hotspot; however, phosphors with both dual-mode sensing capabilities in the near-infrared band have not yet been reported.

[0006] Current research on materials requiring simultaneous stress and temperature dual-mode measurements primarily focuses on stress-sensitive materials across various flexible visible light emission bands. However, it is important to note that the reported upper limits for the measurable force of flexible stress-emitting materials are all less than 100 N, far below the 500-3290 N range experienced by the knee joint during everyday human activity. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a stress- and temperature-controlled dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor, its preparation method, and its applications. This stress- and temperature-controlled dual-mode sensing ytterbium- and neodymium co-doped Sr3Sn2O7 phosphor is a highly robust stress-luminescent material that can be detected through biological tissue under X-ray excitation, with mechanoluminescence signals located at 887 nm, 1100 nm, and 1350 nm, exhibiting very high luminescence intensity. It also possesses unique temperature sensitivity, emitting upconversion luminescence under 980 nm excitation, with emission peaks located at 750 nm, 810 nm, and 860 nm, and the emission peak ratio exhibiting an exponential curve change with increasing temperature. It demonstrates excellent temperature sensitivity. Furthermore, it is noteworthy that both stress luminescence and photoluminescence occur within the near-infrared biological window, facilitating good bio-penetration. Utilizing the superior properties of this material, it holds significant promise for integration with polymethyl methacrylate (PMMA) medical bone cement. This integration provides a new method for bimodal measurement of force and temperature during artificial joint replacement, enabling precise and non-contact monitoring of the condition of the joint prosthesis.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention provides a stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor, including internal doping with Yb. 3+ Source and internally doped Nd 3+ source.

[0010] The stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor achieves stress and temperature dual sensing in the near-infrared band. Its crystal is Sr3Sn2O7, which belongs to the orthorhombic crystal system.

[0011] This invention provides a stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor whose raw materials include a main component, a flux, a dopant, and an internally doped Yb. 3+ Source and internally doped Nd 3+ Source: The expression for the stoichiometric ratio of each element is (1-x)(Sr) 2.99-y Sn2O7:0.01Nd 3+ ,yYb 3+ )-xLi; where x = 0 to 0.4; y = 0.001 to 0.01; more preferably, x = 0.2, y = 0.005, the corresponding phosphor has the best dual-mode sensing effect.

[0012] The main components include strontium-containing compound raw materials and tin-containing compound raw materials, and the main components are internally doped with Yb. 3+ Source and internally doped Nd 3+ The sum of the three sources is 100 mol%.

[0013] The fluxing agent is a compound with fluxing properties, and its molar percentage accounts for (main component + Yb dopant) 3+ Source + Internally Doped Nd 3+ The sum of the three sources is 1 mol%.

[0014] The dopant is a compound that modulates the band gap and defects, and its molar percentage accounts for (main component + internally doped Yb). 3+ Source + Internally Doped Nd 3+ The sum of the three sources (source, source, and source) is 0-20 mol%. Furthermore, when the dopant is not 0 mol%, the band gap of the crystal can be reduced, the electronic transition barrier can be lowered, thereby enhancing luminescence.

[0015] The internally doped Yb 3+ Mole percentage of source (main component + Yb doping) 3+ Source + Internally Doped Nd 3+ The sum of the three sources is 0.1-1 mol%; the internally doped Nd 3+ The molar percentage of the source (main component + Yb doped) 3+ Source + Internally Doped Nd 3+ The sum of the three sources is 1 mol%.

[0016] The strontium-containing compound raw material is preferably one or more of strontium carbonate, strontium oxide, and strontium nitrate.

[0017] The tin-containing compound raw material is preferably one or more of tin oxide, tin disulfide, tin tetrachloride, and tin tetraiodide.

[0018] Preferably, the fluxing agent is one or more of H3BO3, sodium chloride, sodium carbonate, and aluminum fluoride, and the dopant is Li. + Li2CO3 is preferred for introducing Yb. 3+ The source is preferentially introduced with Yb2O3, and internally doped with Nd. 3+ The source is preferentially introduced with Nd2O3.

[0019] Nd 3+ and Yb 3+ Sr in the crystal 2+ Yb 3+ As a sensitizer, Nd 3+ It is the luminescent center.

[0020] The method for preparing the stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor of the present invention includes the following steps:

[0021] S1: Weigh the raw materials according to the raw materials and molar ratio of the stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor, and mix all the raw materials evenly to obtain a mixture.

[0022] In S1, the mixing is carried out by grinding, preferably for 15 to 30 minutes.

[0023] In S1, the purity of the raw materials is all analytical grade or higher. Preferably, the main components are SrCO3 and SnO2, the flux is H3BO3, the dopant is Li2CO3, and Yb is internally doped. 3+ The source material is Yb2O3, with Nd doping. 3+ The raw material for the source is Nd2O3.

[0024] S2: Under an inert atmosphere, the mixture is subjected to solid-phase reduction sintering and then ground to obtain stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor.

[0025] In the S2 process, the solid-phase reduction sintering reaction temperature is 1500–1600℃, and the reaction time is 4–6 h.

[0026] In S2, solid-phase reduction sintering is carried out in a tube furnace. The mixture is placed in a corundum crucible and then on a corundum boat, and finally placed into the tube furnace.

[0027] In step S2, the grinding process lasts for 10 to 30 minutes to ensure the sample is thoroughly ground.

[0028] In S2, the inert atmosphere is preferably a nitrogen atmosphere.

[0029] Furthermore, in the S2 method for preparing stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor, the crucible used is a common high-purity corundum crucible with a mass purity of over 95%, which is placed on a corundum boat.

[0030] The application of the stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor of the present invention is as a stress and temperature dual-mode sensor for monitoring postoperative infection. Specifically, the stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor is prepared into a stress and temperature dual-mode sensor, which is used as an adhesive to fix the artificial joint after joint replacement surgery to the natural bone of the human body, for monitoring stress and temperature, and determining whether postoperative complications and postoperative infection occur.

[0031] The method for fabricating the stress and temperature dual-mode sensor is as follows:

[0032] Step 1: Mix stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor and medical bone cement powder evenly to obtain fluorescent cement mixed powder; by mass ratio, stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor: medical bone cement powder = (1~2): (10~1).

[0033] Step 2: Mix the medical bone cement liquid and fluorescent cement powder until the mixture becomes dough-like, then place it in a mold to shape it, thus obtaining a stress and temperature dual-mode sensor;

[0034] In step 1, the mixing is preferably done by grinding for 20-30 minutes, and the ratio of stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor to medical bone cement powder is preferably 1:4.

[0035] The main component of the medical bone cement powder is methyl acrylate-methyl methacrylate polymer or polymethyl methacrylate polymer. Further, the components and their mass percentages in the medical bone cement powder are as follows: methyl acrylate-methyl methacrylate polymer: 80-90%, zirconium dioxide: 9.5-15%, benzoyl peroxide: 0.5-5%; more preferably, methyl acrylate-methyl methacrylate polymer: 87%, zirconium dioxide: 12%, benzoyl peroxide: 1%.

[0036] In step 2, preferably, the solid-liquid ratio is: fluorescent cement powder: medical bone cement liquid = 8g: 3mL; wherein, medical bone cement liquid: medical bone cement powder = 1g: 0.5mL. The main components and their mass percentages in the medical bone cement liquid are: methyl methacrylate 95-99%, N,N-dimethyl-p-toluidine 1-5%.

[0037] In step 2, the shaping process involves letting the sample stand at room temperature for 10–15 minutes.

[0038] The stress and temperature dual-mode sensor has a maximum force measurement limit of 5000N, a stress sensitivity of 0.1%-0.5% / 10N, and a temperature sensitivity of 1.32%-1.37% at a normal human body temperature of 37℃.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] (1) Stress and temperature sensing: This invention prepares a stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor, which is used to sense stress and temperature. 3+ 、Nd 3+The mechanoluminescence intensity of the dual-doped near-infrared stress-luminescent phosphor was significantly enhanced by the combined use of the flux H3BO3 and the dopant Li2CO3, and it could produce obvious stress luminescence under X-ray excitation through a 4mm thick pigskin. Furthermore, because Yb 3+ With the introduction of [the technology], the sample can generate phonon-assisted upconversion luminescence under 980nm laser irradiation, producing three independent near-infrared photoluminescence peaks. Due to the phonon-assisted transition, these three peaks are extremely sensitive to temperature changes, giving the sample excellent temperature sensing characteristics.

[0041] (2) Stress and temperature sensitivity: This invention prepares a Yb 3+ 、Nd 3+ Double-doped near-infrared stress-emitting phosphors exhibit good physical and chemical stability and excellent stress and temperature sensing capabilities. Compared to existing technologies, the phosphor provided by this invention utilizes Yb... 3+ 、Nd 3+ Double doping achieves a phosphor stress sensitivity of 0.5% / 10N and a temperature sensitivity of 1.37% at a normal human body temperature of 37℃. Yb 3+ 、Nd 3+ The double doping results in Nd under X-ray excitation. 3+ While maintaining near-infrared stress luminescence properties, Yb 3+ Sensitize Nd 3+ The phonon-assisted upconversion luminescence phenomenon was generated under 980nm laser excitation, and the phonon effect gave the sample extremely high temperature sensitivity.

[0042] (3) Application Feasibility: The sample combining the fluorescent powder with medical bone cement exhibited excellent mechanical stability, demonstrating its feasibility for application in joint replacement surgery. Furthermore, the fluorescent powder is electrically passive, possessing potential for miniaturization and offering unique advantages for applications in biological organisms.

[0043] (4) Optimization of luminescence: The luminescence performance of the phosphor is greatly optimized by using the flux H3BO3 and the dopant Li2CO3 in combination.

[0044] (5) Environmental friendliness: Biotoxicity tests show that the fluorescent powder is friendly to the human body and has no toxic effects. The fluorescent powder components do not contain heavy metal compounds such as S, La, Ge, and Lu, nor do they contain sulfides, making it more friendly to the environment and the human body. Attached Figure Description

[0045] Figure 1 For different Yb in Example 1 3+ Powder X-ray diffraction spectra of doped samples ((1)-(5)).

[0046] Figure 2 For different Li in Example 2 + Powder X-ray diffraction spectra of doped samples ((1)-(5)).

[0047] Figure 3 For different Yb in Example 1 3+ Stress emission spectra of samples with different doping concentrations ((1)-(5)) measured under the same conditions; where (a) is the stress emission spectrum of 600nm-1100nm and (b) is the stress emission spectrum of 1100nm-1500nm.

[0048] Figure 4 For different Li in Example 2 + Stress emission spectra of samples with different doping concentrations ((1)-(5)) measured under the same conditions.

[0049] Figure 5 This is an in-situ emission image (taken by a near-infrared camera) of sample (3) in Example 2 during the stress process.

[0050] Figure 6 The stress emission spectrum of sample (3) in Example 2 is a spectrum showing the change in intensity of the integral intensity of the stress emission spectrum as a function of the magnitude of the force.

[0051] Figure 7 The photoluminescence spectrum of sample (3) in Example 2 under 980nm laser excitation as a function of temperature.

[0052] Figure 8 The spectrum of the photoluminescence peak ratio of sample (3) in Example 2 as a function of temperature.

[0053] Figure 9 The dependence spectral lines between different peak positions of photoluminescence in sample (3) in Example 2.

[0054] Figure 10 The spectrum shows the relative sensitivity of temperature measurement of sample (3) in Example 2 as a function of temperature.

[0055] Figure 11 The data are the biotoxicological characterization data of sample (3) in Example 2; (a) is the cell activity diagram of mouse epithelial fibroblasts in different concentrations of Sr3Sn2O7:Nd,Yb powder solution, (b) is the cell activity diagram of human umbilical vein endothelial cells in different concentrations of Sr3Sn2O7:Nd,Yb powder solution, and (c) is the cell activity diagram of mouse embryonic osteoblasts in different concentrations of Sr3Sn2O7:Nd,Yb powder solution.

[0056] Figure 12 This is a conceptual diagram of the application of artificial knee replacement surgery in sample (3) of Example 2.

[0057] Figure 13 The diagram shows the principle of stress-sensing luminescence and temperature-dependent photoluminescence during implementation; where (a) is a schematic diagram of the stress sensing device and (b) is a schematic diagram of the temperature sensitivity sensing device.

[0058] Figure 14 The diagram shows the interaction between stress and temperature signals during the dual-mode sensing process of sample (3) in Example 2. Among them, (a) is a stress luminescence measurement device with a heating stage, (b) is the peak intensity data of stress luminescence under 3000N stress at different temperatures, and (c) is the upconversion photoluminescence intensity and stress luminescence intensity under 980nm laser excitation.

[0059] Figure 15 This is a biological tissue penetration experiment of stress luminescence and upconversion photoluminescence of sample (3) in Example 2; wherein, (a) is a stress luminescence measurement device through pigskin, (b) is the effect of different pigskin thickness on stress luminescence intensity, (c) is a variable temperature upconversion photoluminescence measurement device through pigskin, and (d) is the effect of different pigskin thickness on upconversion photoluminescence.

[0060] Figure 16 The experimental data for the long-term stability, chemical water bath stability, and thermal shock stability of sample (3) in Example 2 are as follows: (a) is a schematic diagram of the compression fatigue test, (b) is a schematic diagram of the water bath stability test, (c) is a schematic diagram of the thermal shock test, (d) is the mechanoluminescence intensity stability of the sample prepared 180 days ago after the compression fatigue test, (e) is the mechanoluminescence intensity stability of the sample after the water bath stability test after the compression fatigue test, and (f) is the mechanoluminescence intensity stability of the sample after the thermal shock test after the compression fatigue test.

[0061] Figure 17 The image shows the effect of mixing sample (3) with medical bone cement before and after in Example 2 on its photoluminescence; where (a) is the I before and after the phosphor binds with PMMA. 810 with I 860 (a) The fluorescence intensity ratio, (b) The relative sensitivity data of the sample before and after the phosphor is bound to PMMA, where the dots and lines represent experimental data and fitting curves, respectively. (c) The normalized s-upconversion photoluminescence spectrum of the powder before and after binding to PMMA under 980nm laser excitation at 309k. Detailed Implementation

[0062] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0063] In the following examples, unless otherwise specified, all raw materials used are commercially available, and all raw materials have a purity of analytical grade or higher.

[0064] The medical bone cement can be selected from commercially available medical bone cement, and is preferably ( ). MV (Heraeus).

[0065] The silicone mold has a cylindrical small hole (Ф=25mm, h=10mm).

[0066] Example 1

[0067] SrCO3, SnO2, Yb2O3, Nd2O3, and H3BO3 were selected as phosphor raw materials. The five groups of compound raw materials were accurately weighed according to the molar mass ratio of each element, and the formulations are as follows:

[0068] (1) 2.99SrCO3-2SnO2-0Yb2O3-0.005Nd2O3-0.01H3BO3 (Comparative Example 1)

[0069] (2) 2.9875SrCO3-2SnO2-0.00125Yb2O3-0.005Nd2O3-0.01H3BO3 (Example 1)

[0070] (3) 2.985SrCO3-2SnO2-0.0025Yb2O3-0.005Nd2O3-0.01H3BO3 (Example 2)

[0071] (4) 2.9825SrCO3-2SnO2-0.00375Yb2O3-0.005Nd2O3-0.01H3BO3 (Example 3)

[0072] (5) 2.98SrCO3-2SnO2-0.05Yb2O3-0.005Nd2O3-0.01H3BO3 (Example 4)

[0073] The total weight of the mixture was controlled at 3g. 3g of the mixture was accurately weighed, poured into an agate mortar and ground for 20 minutes, then placed in a corundum crucible. The corundum crucible was then placed on a corundum boat and placed in a high-temperature tube furnace. The heating rate was precisely controlled: 10℃ / min below 1200℃ and 5℃ / min above 1200℃. Under a high-purity nitrogen atmosphere, the sample was directly heated from room temperature to 1200℃ and held at 1200℃ for 20 minutes, then heated to 1550℃ and held for 5 hours. After the holding period, the temperature was lowered to 400℃ after 500 minutes and then allowed to cool naturally in the furnace. This yielded a stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor, whose expression is: Sr... 2.99-y Sn2O7:0.01Nd 3+ ,yYb3+ (Where, y = 0, 0.0025, 0.005, 0.0075, and 0.01 correspond to Comparative Example 1 and Examples 1-4, respectively). The heating rate and cooling rate are recommended settings for high-temperature tubular furnaces.

[0074] Example 2

[0075] SrCO3, SnO2, Yb2O3, Nd2O3, Li2CO3, and H3BO3 were selected as phosphor raw materials. The six groups of compound raw materials were accurately weighed according to the molar mass ratio of each element, and the formulations are as follows:

[0076] (1) 1(2.985SrCO3-2SnO2-0.0025Yb2O3-0.005Nd2O3)-0Li2CO3-0.01H3BO3 (Example 5)

[0077] (2) 0.9(2.985SrCO3-2SnO2-0.0025Yb2O3-0.005Nd2O3)-0.05Li2CO3-0.01H3BO3 (Example 6)

[0078] (3) 0.8(2.985SrCO3-2SnO2-0.0025Yb2O3-0.005Nd2O3)-0.1Li2CO3-0.01H3BO3 (Example 7)

[0079] (4) 0.7(2.985SrCO3-2SnO2-0.0025Yb2O3-0.005Nd2O3)-0.15Li2CO3-0.01H3BO3 (Example 8)

[0080] (5) 0.6(2.985SrCO3-2SnO2-0.0025Yb2O3-0.005Nd2O3)-0.2Li2CO3-0.01H3BO3 (Example 9)

[0081] The total weight of the mixture was controlled to be 5g. 5g of the mixture was accurately weighed, ground in an agate mortar for 20 minutes, and then placed in a corundum crucible. The corundum was then placed in a high-temperature tube furnace. The heating rate was precisely controlled: 10℃ / min below 1200℃ and 5℃ / min above 1200℃. Under a high-purity nitrogen atmosphere, the sample was directly heated from room temperature to 1200℃ and held at 1200℃ for 20 minutes, then heated to 1550℃ and held for 5 hours. After the holding period, the temperature was lowered to 400℃ after 500 minutes and then allowed to cool naturally in the furnace. This yielded a stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor, whose expression is (1-x)(Sr... 2.985 Sn2O7:0.01Nd 3+ 0.0025Yb 3+ )-xLi(x=0, 0.1, 0.2, 0.3, 0.4).

[0082] X-ray diffraction (XRD) spectra of all stress- and temperature-controlled dual-mode ytterbium-neodymium co-doped Sr3Sn2O7 phosphor samples were determined using a Rigaku D / MAX 2550VB XRD system. The test voltage was 40 kV, the scan speed was 10° / min, and Cu-Kα rays were used. Figure 1 and Figure 2 As shown, the X-ray diffraction results, compared with the PDF card analysis in JADE, indicate that the crystals precipitated in Examples 1 and 2 are both Sr3Sn2O7, belonging to the orthorhombic crystal system, indicating that Nd... 3+ Yb 3+ and Li + The doping did not affect the formation of the crystal phase.

[0083] Application Example 1

[0084] To conduct stress luminescence testing, the stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor obtained in Examples 1 and 2 was ground for 20 minutes. 1.6g of the stress and temperature dual-mode sensing ytterbium-neodymium co-doped Sr3Sn2O7 phosphor and 6.4g of medical bone cement powder were placed in an agate mortar and ground for 20 minutes. The well-mixed powder was poured into a beaker, and 3ml of medical bone cement liquid was added. The mixture was rapidly stirred with a glass rod for 30 seconds until it resembled a dough. For ease of subsequent testing, the sample was poured into a silicone mold (Ф=25mm, h=15mm) and left to stand at room temperature (26℃) for 12 minutes. The sample was then removed from the mold. The sample size can be customized based on the mold selection and subsequent cutting methods. The cured sample was cut and polished into a 10mm thick, 25mm diameter cylinder for subsequent mechanoluminescence testing. The cured sample was cut and polished into a thin slice with a thickness of 2 mm for subsequent photoluminescence temperature measurement.

[0085] The main components of the medical bone cement powder are methyl acrylate-methyl methacrylate polymer (87 wt.%), zirconium dioxide (12 wt.%), and benzoyl peroxide (1 wt.%). The main components of the medical bone cement liquid are methyl methacrylate (98 wt.%) and N,N-dimethyl-p-toluidine (2 wt.%).

[0086] A domestically produced stress luminescence measurement system was adopted, which mainly consists of three parts: a 365nm ultraviolet LED and an X-ray tube, a general-purpose testing machine (China SUST CMT 1104), and two high-sensitivity CCD spectrometers (Canada Horiba Lumetta and Ocean Optics NIRQuest 1.7 fiber optic spectrometer). Figure 3 As can be seen from the stress luminescence intensity comparison diagram of Example 1, with Yb 3+ Increasing the doping concentration led to a sharp decrease in mechanoluminescence intensity, while Yb doping enhanced the intensity of upconversion photoluminescence excited at 980 nm. Therefore, a sample with a Yb doping concentration of 0.5 mol% was selected for subsequent optimization experiments. Figure 4 As can be seen from the comparison diagram of the mechanoluminescence intensity of Example 2, the sample corresponding to Example 7 has the strongest stress luminescence intensity, corresponding to x = 0.2.

[0087] Figure 5 The image shows the in-situ emission of the sample corresponding to Example 7 in Example 2 under stress. The near-infrared camera used was SPLG-Mars640 from Benona (Shenzhen) Technology Co., Ltd. It can be clearly seen that the near-infrared stress emission intensity and emission area distribution change with the applied stress.

[0088] Figure 6 The stress emission peak intensity of the sample corresponding to Example 7 in Example 2 shows the intensity change trend as the magnitude of the force changes. By fitting this curve, it can be found that the stress emission peak intensity shows a simple linear change trend with the magnitude of the applied stress. The corresponding formula is: emission peak position integral intensity = 520413 + 372 * stress value (N), which has the potential for stress sensing.

[0089] Figure 7 The photoluminescence spectrum of the sample corresponding to Example 7 in Example 2 under 980nm laser excitation as a function of temperature is shown. To mitigate the potential impact of laser heating on the sample, a low pump power of 0.32W was used, corresponding to a power density of only 6W / cm². 2 As shown in the figure, the phonon-assisted upconversion luminescence generated by the sample under 980 nm excitation light exhibits a significant increase in intensity with temperature, reaching a 99-fold increase at 773 K. This temperature-dependent behavior is attributed to the phonon-induced upconversion luminescence from Yb 3+ To Nd 3+ Thermally enhanced phonon assistance.

[0090] Figure 8 The photoluminescence peak ratio of the sample corresponding to Example 7 in Example 2 changes with temperature, and the corresponding fitting formula is: Where C is a host-dependent parameter, which has a complex relationship with the radiative transition rate, degeneracy, and emission angular frequency of the thermally coupled energy level. ΔE is the energy difference between the thermally coupled energy levels, k... B Let C be the Boltzmann constant, T be the temperature in Kelvin. The fitted values ​​of C and ΔE are as follows: Figure 8 As shown in the figure, the ratios of the three peak values ​​of photoluminescence in the sample (750 / 810, 750 / 860, and 810 / 860) gradually increase with increasing temperature. This indicates that the effect of phonon thermal radiation gradually strengthens with increasing temperature, thereby increasing the probability of electrons transitioning to higher energy levels.

[0091] Figure 9 The graph shows the dependence spectral lines between the peak values ​​of the samples corresponding to Example 7 in Example 2. It can be seen from the graph that there is good linearity between 1 / T and Ln(FIR), indicating that Nd... 3+ The three energy levels 4 F 7 / 2 , 4 F 5 / 2 and 4 F 3 / 2 The two peaks can produce relatively independent emission positions for temperature measurement.

[0092] Figure 10 The graph shows the relative sensitivity of the sample corresponding to Example 7 in Example 2 as a function of temperature. It can be seen from the graph that the relative sensitivity gradually decreases with increasing temperature. 750 / I 860 The relative sensitivity reaches a maximum of 2.81% at 413 K. According to I... 810 / I 860 The relative sensitivity of the intensity ratio over the biological temperature range was 1.33% (at 309 K). No significant emission peak was observed at the 750 nm peak below 413 K, but the intensity at the 750 nm peak increased sufficiently to be clearly distinguishable from background noise at 413 K. This can be achieved using Nd... 3+ This can be explained by the thermal relaxation between different energy levels. Specifically... 4 F 3 / 2 and 4 F 5 / 2 The energy level only undergoes a significant multiphonon-assisted up-transition at temperatures exceeding 413 K. 4 F 7 / 2 The energy level then produces a 750nm peak emission sufficient to be captured by the detector.

[0093] Before any biological application, it is important to understand the cytotoxicity of the sample under study. Therefore, a comprehensive cell viability assay was performed on the sample corresponding to Example 7 in Example 2 using three different cell lines. Figure 11As shown, mouse epithelial-like fibroblasts (L929 cells), human umbilical vein endothelial cells (Huvec cells), and mouse embryonic osteoblast progenitor cells (MC3T3-E1 cells) were exposed to solutions containing different concentrations of the powder sample. Biocompatibility was assessed in the concentration range from 0 μg / ml (control group) to 1000 μg / ml. Notably, cell viability remained above 90% for all samples from Examples 1-9, indicating that this fluorescent powder has no biotoxic side effects and is biocompatible.

[0094] The preparation process of the near-infrared dual-mode sensing phosphor, its embedding in medical bone cement, and its combination with artificial bone cement for measuring stress and temperature are illustrated in the diagram below. Figure 12 As shown, high-performance phosphors were sintered by incorporating flux H3BO3 and dopant Li2CO3 under a high-purity nitrogen atmosphere. The phosphors and medical bone cement powder were then ground evenly in an agate mortar. The powder was poured into a beaker, and medical bone cement slurry was added. After rapid stirring with a glass rod, the mixture was used to fix the artificial joint to the natural bone of the human body. Combined with a laser and X-ray source, the stress and temperature at the contact point between the artificial joint and the natural bone could be measured in situ inside the organism.

[0095] The self-built mechanoluminescence and photoluminescence experimental devices, such as Figure 13 As shown; (a) is a schematic diagram of a stress sensing device, in which the prepared sample is placed on a pressure testing machine, and the test pressure is transmitted to the computer through a signal sensor; (b) is a schematic diagram of a temperature sensitivity sensing device, in which the prepared sample is placed in a heating stage for heating, and the test temperature change is transmitted to the computer through a signal sensor.

[0096] From an application perspective, distinguishing the potential interaction between force and temperature on the recorded luminescence signal is crucial. Therefore, a verification experiment was conducted using the dual-mode sensing sample corresponding to Example 7 in Example 2 to verify the interaction between stress and temperature signals during dual-mode sensing, such as... Figure 14 As shown, the dual-mode sensing sample and optical fiber were connected and placed on a heating stage. Stress emission spectra under 3000N stress were measured at different temperatures within the range of 297-373°C. The results showed that the stress emission intensity remained stable at different temperatures, almost unaffected by temperature changes. On the other hand, the stress emission spectrum under 3000N stress after 980nm laser excitation was measured. The fact that no stress emission signal was detected under 980nm laser excitation indicates that the 980nm laser is inefficient at charging the stress-emitting phosphor. Therefore, our bifunctional material is recommended to be used in the following way: firstly, the peak-to-peak ratio of the near-infrared emission peak excited by 980nm laser can be used to measure the temperature, since 980nm excitation cannot generate any stress emission signal; then, the stress can be measured using the stress emission signal excited by X-rays.

[0097] The biological tissue penetration experiment of the dual-mode sensing sample corresponding to Example 7 in Example 2, involving stress luminescence and upconversion photoluminescence, is as follows: Figure 15 As shown, a dual-mode sensing sample was placed on one side of pigskin, and a filter was placed on the other side. The filter was connected to an optical fiber to collect stress-induced emission signals, and a 980nm laser was used to illuminate the pigskin. The stress-induced emission intensity monotonically decreased with increasing pigskin thickness. Notably, even with a pigskin thickness of 15mm, a clear stress-induced emission signal could be recorded. Figure 15 (a) Similarly, the intensity of upconversion photoluminescence also decreases with increasing pigskin thickness. Figure 15 (b) A clear upconversion photoluminescence signal could still be detected at a thickness of 6 mm, indicating that the near-infrared emission of the sample has good bio-penetration.

[0098] The long-term stability of the sample from Example 7 (No. 3) in Example 2 after bonding with bone cement was verified by the following tests (e.g., Figure 16 As shown): First, a sample prepared 180 days prior was subjected to a cyclic compression fatigue test by compressing it 1000 times under a stress of 5000N. Figure 16 (a)). Next, another sample was immersed in a 310K water bath (close to normal human body temperature) for 7 days to test its chemical stability. Figure 16 (b) Then, 1000 compression fatigue tests were performed. Finally, the samples were subjected to a 10-hour thermal shock test (cooled at 253K for 1 hour, then immediately heated at 310K for 1 hour, the entire process was repeated 5 times). Figure 16 (b) Then, 1000 cyclic compression fatigue tests were performed. After each test, the samples were measured under 10 cyclic force loads and compared with untreated control samples. Notably, the stress luminescence intensity showed almost no change, with a variation of less than 3%, reflecting the robustness of the samples. Figure 16 (d)-(f)). After the above tests, even under a pressure of 10,000 N, no obvious deformation or damage was observed in the samples.

[0099] After mixing the phosphor with medical bone cement, its relative temperature sensitivity (x-value) and upconversion photoluminescence curve remained unchanged. The I-value of the phosphor changed before and after bonding with the medical bone cement. 810 / I 860 The ratios show a high degree of consistency. Figure 17 (a)). For example, at a normal human body temperature of 309 K, the sensitivity of powder samples is 1.33%, while the sensitivity after embedding in medical bone cement is 1.32%. Figure 17 (b)). Figure 17(c) shows the normalized upconversion photoluminescence spectra of the powder before and after embedding into medical bone cement at 309K under 980nm laser excitation. It can be seen that the normalized emission spectra are completely overlapping and have a high degree of consistency in peak shape.

[0100] Through the above experiments, it can be seen that when x = 0.2 and y = 0.005 (Example 7), the dual-mode sensing effect is optimal.

[0101] same comparison Figure 4 The data shows that even without the addition of dopants, it still exhibits significant mechanoluminescence, but the intensity is only about half that of the dopant-added version, indicating that the addition of dopants can improve the intensity of mechanoluminescence.

Claims

1. A stress and temperature dual-mode sensing Yb and Nd co-doped Sr3Sn2O7 phosphor, characterized in that, The raw material of the stress and temperature dual-mode sensing Yb and Nd co-doped Sr3Sn2O7 fluorescent powder comprises a main component, a fluxing agent, a dopant and Yb 3+ source and internal Nd doping 3+ Source: the expression formed by the stoichiometric ratio of each element is (1-x)(Sr 2.99-y Sn2O7:0.01Nd 3+ ,yYb 3+ )-xLi; wherein x=0-0.4; y=0.001-0.01; the dopant is introduced by using Li2CO3. 2.The stress and temperature dual-mode sensing Yb3+and Nd3+co-doped Sr3Sn2O7 fluorescent powder of claim 1, wherein, The stress and temperature dual-mode sensing Yb-Nd co-doped Sr3Sn2O7 fluorescent powder realizes stress and temperature dual-mode sensing in a near-infrared wave band, and the crystal is Sr3Sn2O7 and belongs to an orthorhombic system. 3.The stress and temperature dual-mode sensing Yb3+and Nd3+co-doped Sr3Sn2O7 fluorescent powder of claim 1, wherein, The host component includes a strontium-containing compound raw material and a tin-containing compound raw material, the host component, the inner-doped Yb 3+ source and the inner-doped Nd 3+ The sum of the three is 100 mol%. The fluxing agent is a compound having a fluxing effect, the molar percentage of which accounts for 0.1-10% of the host component and the internal Yb doping 3+ Source and internal Nd doping 3+ The sum of the three is 1 mol%. The molar percentage of the dopant accounts for 0-20 mol% of the host component and the inner-doped Yb 3+ Source and inner-doped Nd 3+ The sum of the three sources is 0-20 mol%. The inner-doped Yb 3+ The molar percentage of the source accounts for the main component and the inner-doped Yb 3+ The inner-doped Nd 3+ The sum of the three sources is 0.1-1 mol%. The inner Nd 3+ The molar percentage of the source of Yb 3+ The inner Nd 3+ The sum of the three sources is 1 mol%. 4.The stress and temperature dual-mode sensing Yb3+and Nd3+co-doped Sr3Sn2O7 fluorescent powder of claim 3, wherein, The raw material of the strontium-containing compound is one or more of strontium carbonate, strontium oxide and strontium nitrate; and / or, the raw material of the tin-containing compound is one or more of tin oxide, tin disulfide, tin tetrachloride and tin tetraiodide; and / or, the fluxing agent is one or more of H3BO3, sodium chloride, sodium carbonate and aluminum fluoride; and / or, the internal doping Yb 3+ source is introduced in the form of Yb2O3, and the internal doping Nd 3+ source is introduced in the form of Nd2O3.

5. The preparation method of the stress and temperature dual-mode sensing Yb3+ and Nd3+ co-doped Sr3Sn2O7 fluorescent powder according to any one of claims 1-4, characterized in that, The method comprises the following steps: S1: according to the raw materials and the molar ratio of the stress and temperature dual-mode sensing Yb-Nd co-doped Sr3Sn2O7 fluorescent powder, the raw materials are weighed and mixed uniformly to obtain a mixture; S2: under an inert atmosphere, the mixture is subjected to solid-phase reduction sintering, and then ground to obtain the stress and temperature dual-mode sensing Yb-Nd co-doped Sr3Sn2O7 fluorescent powder.

6. The preparation method of stress and temperature dual-mode sensing Yb3+ and Nd3+ co-doped Sr3Sn2O7 fluorescent powder according to claim 5, characterized in that, In S2, the reaction temperature of the solid-phase reduction sintering is 1500-1600 DEG C, and the reaction time is 4-6 h.

7. Use of the stress and temperature dual-mode sensing Yb3+ and Nd3+ co-doped Sr3Sn2O7 phosphor according to any one of claims 1 to 4 for the preparation of a stress and temperature dual-mode sensor, characterized in that, The upper limit of the measured force of the stress and temperature dual-mode sensor is 5000 N, the stress sensitivity is 0.1%-0.5% / 10 N, and the temperature measurement sensitivity is 1.32%-1.37% at a normal human body temperature of 37 DEG C.

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