PAA-NaYF4∶Yb3+,Tm3+@NaYF4核壳型稀土掺杂上转换纳米材料的制备和发光性能分析OA

To enhance the performance and expand the application fields of rare-earth-elements-doped upconversion nanomaterials(REEs-UCNPs),NaYF4∶Yb3+,Tm3+@NaYF4 core-shell upconversion nanomaterials were successfully synthesized via a solvothermal method in this study.Key synthesis parameters,including the core-shell ratio,reaction temperature,reaction time,and oleic acid(OA)/octadecene(ODE)volume ratio,were systematically optimized to achieve optimal results.The effects of these conditions on the morphology and luminescence properties of the materials were comprehensively investigated using transmission electron microscopy,X-ray diffraction,fluorescence spectroscopy,scanning electron microscopy,CIE chromaticity analysis,Fourier transform infrared spectroscopy,and Zeta potential measurements.The results indicated that the optimal synthesis conditions were as follows:a core-to-shell molar ratio of 1∶0.5,a reaction temperature of 300℃,a reaction time of 90 min,and an OA/ODE volume ratio of 4.8:12.Based on these conditions,polyacrylic acid(PAA)-surface-modified composite materials,denoted as PAA-NaYF4∶Yb3+,Tm3+@NaYF4,were successfully prepared via a ligand exchange method.Characterization results revealed that the modified nanoparticles retained their original crystal phase and morphology,with a uniform particle size distribution and an average diameter of(43.72±0.22)nm.Furthermore,the dispersibility and water solubility were significantly improved.In terms of luminescence performance,the PAA-modified materials still exhibited blue upconversion fluorescence under 980 nm near-infrared excitation.Zeta potential analysis confirmed the successful coating of PAA,as the nanoparticle surface carried a negative charge.The successful synthesis of this material laid a solid foundation for its potential applications in bioimaging and sensing.