Rb2InCl5·H2O doped with Te4+ for fluorescence thermometry and coordinated water-related structural phase transformation

Here, we synthesized Rb 2 InCl 5 ·H 2 O with x Te 4+ doping by the coprecipitation method, which converts the original nonluminance for pure Rb 2 InCl 5 ·H 2 O into orange luminescence ascribed to Te 4+ incorporation with an emission peak at 648 nm and a full width at half maximum of 142 nm (420.3 meV) at room temperature. The photoluminescence (PL) lifetime of Te 4+ -doped Rb 2 InCl 5 ·H 2 O exhibits a strong temperature dependence, with a maximum absolute sensitivity ( S A ) of 12 × 10 −3 K −1 at 260 K and a relative sensitivity ( S R ) of 3.5%K −1 at 300 K, demonstrating its capability for non-contact remote temperature measurement. Additionally, we capture the dynamic changes of coordinated water with temperature in Rb 2 InCl 5 ·H 2 O through temperature-dependent Raman spectroscopy, analyze the resulting structural phase transformation associated with coordinated water, and investigate the reversibility of this phase transformation.