Eulytite-type Ba₃Yb(PO₄)₃:Tm/Er/Ho as a high sensitivity optical thermometer over a broad temperature range

Abstract

Doping with Tm, Er, and Ho achieved blue, green, and red emission, respectively. BYP:Tm/Er/Ho achieved Sr > 0.63% K−1 over the temperature range of 303–603 K.

Enabling Nonthermally Coupled Upconversion in a Core–Shell–Shell Nanoparticle for Ultrasensitive Nanothermometry and Anticounterfeiting

“…However, it should be noted that these thermal sensitivity values are still low and hard to be further improved due to intrinsic confinement by the Boltzmann distribution theory. − Importantly, recent works showed that some emissions from the nonthermally coupled energy levels of two lanthanides can overcome this issue for highly sensitive LIR-based temperature sensors. − For instance, the design of the NaYF 4 :Yb/Nd@NaYF 4 @NaYF 4 :Yb/Er core–shell–shell nanostructure resulted in a high relative sensitivity of 9.6% K –1 due to the luminescence thermal enhancement of Nd 3+ and luminescence thermal quenching of Er 3+ with increasing temperature . However, at present, only several lanthanides can be used as dual emitters for the highly thermosensitive upconversion. − Also, a simple codoping of the dual emitters in materials still showed low temperature sensitivity. − So far, it has remained a challenge for the development of ultrasensitive nanothermometry based on nonthermally coupled upconversion systems.…”

Achieving high-sensitivity dual-mode optical thermometry via phonon-assisted cross-relaxation in a double-perovskite structured up-conversion phosphor

“…For UC luminescent materials used in optical thermometry, high-quality matrix crystals are one of the key elements to achieve accurate and efficient optical thermometers. 14–18 Fluoride matrix crystals (such as NaYF 4 , SrF 2 , LuF 3 , etc .) normally exhibit efficient UC luminescence due to their low phonon energy.…”