The synthesis of Er3+/Yb3+/K+ triple-doped NaYF4 phosphors and its high sensitivity optical thermometers at low power

摘要

Optical Thermometry is popular among researchers because of its non-contact, high sensitivity, and fast measurement properties. In the present experiment, Er3+/Yb3+/K+ co-doped NaYF4 nanoparticles with dif-ferent K+ concentrations were synthesized by solvothermal method, and the samples showed bright up -conversion green emission under the excitation of a 980 nm laser. The powder X-ray diffractometer and transmission electron microscope were used to characterize the crystal structure and its surface mor-phology, respectively. The spectral characteristics of nanoparticles with K+ doping concentration from 10% to 30% (Molar ratio) were investigated by fluorescence spectroscopy, and it was observed that the fluor-escence intensity reached the maximum at the K+ concentration of 20%, after which the intensity weakened when the K+ content continued to increase. According to the dependence between the luminescence in-tensity of the sample and the laser power density and fluorescence lifetime, the intrinsic mechanism was carefully investigated. Temperature-dependent spectra of the samples were recorded in the temperature range of 315-495 K, and the maximum values of absolute sensitivity (Sa) and relative sensitivity (Sr) were measured at 0.0041 K-1 (455 K) and 0.9220%K-1 (315 K). The experimental results show that K+/Er3+/Yb3+ triple-doped NaYF4 green fluorescent nanoparticles (GFNs) have good prospects for applications in display devices, temperature sensing, and other fields.

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