Role of SiO₂ Coating on YAG:V³⁺,Nd³⁺ Nanoparticles in Luminescence Thermometry

Coating luminescent nanoparticles with a SiO2 shell provides numerous benefits, which include improving the dispersibility of nanoparticles, reducing their cytotoxicity, and facilitating their biofunctionalization. However, from the perspective of luminescent thermometry, it is important that such a procedure does not alter the thermometric properties of the luminescent nanothermometer. Therefore, in this work, the effect of the SiO2 encapsulation procedure on the thermometric properties of YAG:V3+,Nd3+ nanoparticles was investigated. It was demonstrated that increasing the thickness of the SiO2 layer increases the thermal stability of the luminescence of V3+ ions. However, it was demonstrated that a high relative sensitivity of 1.5%/K at 500 K can be maintained for a luminescence thermometer while keeping a thin SiO2 shell.