Near-Infrared Ratiometric Nanothermometer in Yb3+/Nd3+ Co-Doped Nanocrystals

Nanothermometers that can reflect temperature in real-time are crucial for photothermal therapy. Near-infrared (NIR) fluorescent probes that conform to Boltzmann distribution will play an important role if they have the above characteristics. Here, the LiLuF 4 : Nd 3+ /Yb 3+ nanocrystals were designed and synthesized by control, exhibiting multiple bright near-infrared emission peaks at 925–1080 nm region at 280–360 K under the excitation of an 808 nm laser. The feasibility of being used as a nanothermometer was confirmed by testing the spectral variation with temperature and analysis.