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

Here, we synthesized Rb₂InCl₅·H₂O with x Te⁴⁺ doping by the coprecipitation method, which converts the original nonluminance for pure Rb₂InCl₅·H₂O into orange luminescence ascribed to Te⁴⁺ 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 Te⁴⁺-doped Rb₂InCl₅·H₂O exhibits a strong temperature dependence, with a maximum absolute sensitivity (SA) of 12 × 10^-3K^-1 at 260 K and a relative sensitivity (SR) 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 Rb₂InCl₅·H₂O through temperature-dependent Raman spectroscopy, analyze the resulting structural phase transformation associated with coordinated water, and investigate the reversibility of this phase transformation.