Lanthanide and transition metals doped materials for non-contact optical thermometry with promising approaches

Temperature is a fundamental physical quantity whose precise measurement is critical in research and technology. Temperature detection based on the optical response of the luminescence materials has piqued interest because it can overcome the limitations of classical contact thermometers and meet the requirements of non-contact thermometers that are not addressed by conventional contact thermometers. In this review, we looked at the most recent and significant advances made using various temperature sensing technologies based on the luminescence intensity ratio of thermally coupled energy levels of lanthanide ions. Temperature-dependent decay time, optical thermometry via temperature-induced spectral tuning of the characteristics charge transfer band (CTB) edge of lanthanides doped rare earth vanadate (Re: gadolinium [Gd], lutetium [Lu], yttrium [Y]) ReVO4 (Re = Gd, Lu, Y) phosphors, and a temperature sensing method based on thermally populated low-lying energy levels of ions of samarium, europium, erbium, yttrium, holmium, thulium, or terbium (Sm3+, Sm2+, Eu3+, Er3+, Y3+, Ho3+, Tm3+, and Tb3+) doped phosphors have all been thoroughly reviewed. The physical mechanism, thermoluminescence characteristics, temperature detection range, and sensitivity of the materials are discussed in detail. The advantages and disadvantages of each approach have been compared. Finally, a further research direction based on temperature sensing has been suggested.