Temperature Sensing And Photothermal Properties Research On Rare Earth Doped NaLuF₄/CuS Composite

In recent years,the treatment of cancer cells has received widespread attention by using nano-photothermal materials,including copper sulfide（CuS）nano-materials with near-infrared absorption.In the photothermal therapy（PTT）,the temperature will not only affect the photothermal effect,but also interfere with normal tissue cells.So,precise temperature control and real-time measurement are extremely important.In the temperature measurement,rare earth-doped up-conversion luminescent materials have shown excellent temperature measurement capabilities,especially the use of fluorescence intensity ratio.Therefore,the optical properties,temperature sensing properties,and photothermal properties of NaLuF₄:Yb³⁺,Ho³⁺and copper sulfide have been studied,and finally the NaLuF₄/CuS composite material with temperature sensing properties and photothermal properties was synthesized.The details are as follows:（1）The solvothermal method was used to prepare and study the luminescence properties of NaLuF₄:Yb³⁺,Ho³⁺(Er³⁺/Tm³⁺).After that,the Yb³⁺and Ho³⁺doped NaLuF₄nanomaterials were selected as the research object,and the luminous intensity was improved by doping with alkali metal ions Ca²⁺and Mg²⁺.By doping with different concentrations of Ca²⁺ions,it is found that all samples have increased luminescence.When the concentration is 3%,the luminescence is the strongest.After being doped with Ca²⁺at303-333 K,the fluorescence intensity shows an exponential curve compared with the temperature measurement fitting.At 303 K,it has the maximum temperature measurement sensitivity of 0.080%K^-1.（2）A small size CuS with a particle size of about 10.13 nm was successfully prepared by using a one-step water bath method,which is basically spherical and has a hexagonal crystal phase structure.By adjusting the reaction parameters,the optimal preparation conditions are obtained,and it is proved that copper sulfide has a good light absorption effect in the near infrared region.Irradiated by 808 nm with different power densities of 1W/cm² and 2 W/cm²,the CuS solution has good physical and chemical stability and good photothermal effect,and the maximum photothermal efficiency can reach 63.2%.（3）The NaLuF₄/CuS composite material was synthesized,and the composite material was successfully prepared through TEM characterization,EDS characterization,Ze Ta potential analysis,and FTIR analysis.Through the study of luminescence properties,the luminescence intensity of NaLuF₄:Yb³⁺,Ho³⁺,Ca²⁺has been significantly improved after coating SiO₂.In the temperature range of 303-353 K,the NaLuF₄/CuS composite exhibits the same fluorescence intensity change law as that of NaLuF₄:Yb³⁺,Ho³⁺,Ca²⁺and the temperature of the sample after composite CuS is significantly higher than that of single NaLuF₄:Yb³⁺,Ho³⁺,Ca²⁺within 600 s.Finally,this kind of multifunctional nanometer thermometer with applicationpotential is expected to promote its further research and development in biomedicie.