Preparation of core–shell structured NaYF4:Yb3+/Tm3+@NaYF4:Yb3+/Er3+ nanoparticles with high sensitivity, low resolution and good reliability and application of their fluorescence temperature properties

By doping Tm 3+ and Er 3+ with core–shell partitioning, not only a significant increase in fluorescence intensity could be achieved, but also simultaneous temperature measurements on multiple thermocouple energy levels could be realised.