LaOF:Yb3+, Er3+ Upconversion Nanophosphors Operating at Low Laser Powers for Nanothermometry Applications

Luminescence nanothermometers based on LaOF:Yb3+, Er3+ upconversion nanoparticles (UCNPs) were investigatedinthis study. The fluorescence intensity ratio (FIR) of the UCNPs wasrecorded in the visible (red) and near-infrared (NIR) regions at differenttemperatures. The impact of laser heating on the UCNPs was preventedby identifying the optimal operating conditions of the laser thatcould be used to record the FIRs without compromising the integrityof the UCNPs. The behavior of the UCNPs against the laser exposuretime and power was analyzed to recognize the critical point of thelaser power, below which laser heating of the UCNPs was negligible.This approach can be perceived as a benchmark for testing luminescentmaterials using nanothermometry.

Automated summary

Luminescence nanothermometers based on LaOF:Yb3+, Er3+ upconversion nanoparticles were studied. The fluorescence intensity ratio (FIR) of the nanoparticles was recorded at different temperatures in the visible and near-infrared regions. Optimal laser conditions were identified to prevent laser heating of the nanoparticles. The behavior of the nanoparticles under laser exposure was analyzed to determine the critical laser power below which laser heating was negligible. This approach serves as a benchmark for testing luminescent nanothermometers.