Lanthanide-based thermometers: At the cutting-edge of luminescence thermometry

Present technological demands in micro and nanoelectronics, photonics, micro and nanofluidics, and biomedicine, among other areas, have reached a point such the use of conventional contact thermometers is not able to make measurements when spatial resolution decreases to the submicron scale. The development of novel non-contact thermal probes is, then, mandatory, contributing to an expansionary epoch of luminescence thermometry. Luminescence thermometry based on trivalent lanthanide ions becomes very popular since 2010 due to the unique versatility, stability and narrow emission band profiles of the ions that cover the entire electromagnetic spectrum with relatively high emission quantum yields. Here we give a perspective overview of the field since the beginnings in the 1950’s until the most recent cutting-edge examples. The current movement towards the use of the technique as a tool for thermal imaging, early tumor detection and as a tool for unveiling properties of the thermometers themselves or of their local surroundings is also summarized.