Primary Luminescent Nanothermometers for Temperature Measurements Reliability Assessment
Joana Costa Martins, Ana R. N. Bastos, Rute A. S. Ferreira, Xin Wang, Guanying Chen, Luís D. Carlos
Abstract
The potential applications in disparate fields led to a rapid evolution of luminescence thermometry. In particular, luminescent thermometry based on trivalent lanthanide ions (Ln 3+ ) has become very popular in the past decade due to the unique versatility, stability, and narrow emission band profiles covering a broad spectral range (from ultraviolet to the infrared) with relatively high emission quantum yields. Nevertheless, the reliability of Ln 3+ ratiometric nanothermometry measurements is recently questioned in a few works reporting fake temperature readouts caused by experimental artifacts and even intrinsic effects. Using NaYF 4 :Er 3+ /Yb 3+ @NaNdF 4 @PAA (PAA stands for polyacrylic acid) core–shell nanoparticles, it is shown that how the primary luminescent thermometer concept can be used to correct the thermometric parameter (the intensity ratio of the Er 3+ 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions) from the interference of the intruding 2 H 9/2 → 4 I 13/2 emission ensuring, thereafter, reliable temperature measurements.