Multisignal optical temperature‐sensing properties of Eu3+‐doped NaYF4 nanoparticles

In this paper, the multisignal (different emissions/colours) temperature sensing of NaYF4 :Eu3+ nanoparticles is investigated, which is based on fluorescence intensity ratios (FIRs) between 5 D0 →7 FJ (J=1-4) and 5 D1 →7 FJ' emissions. The 5 D1 →7 FJ' (J'=0-2) emissions can be clearly observed due to the low photon energy of NaYF4 . Based on the FIRs between different 5 D0 →7 FJ and 5 D1 →7 FJ' emissions, higher absolute/relative temperature sensitivities are obtained. Compared with the FIR between whole 5 D0 →7 FJ and 5 D1 →7 FJ' emissions, the maximum value of Sa was improved from 0.27 K-1 to 5.02 K-1 and that of Sr was improved from 0.89%·K-1 to 1.27%·K-1 . Furthermore, the FIRs between different colours of emissions were investigated for the application of wide-range multicolour temperature sensing.