Vacancy-ordered Te⁴⁺-doped Rb₂ZrCl₆ double perovskite microcrystals for solid-state lighting and non-contact optical thermometry

In this work, we prepared the highly efficient yellow light-emitting vacancy-ordered Te⁴⁺-doped Rb₂ZrCl₆ microcrystals (RZCTs) through a hydrothermal method. RZCT with a photoluminescence quantum yield of 34.6% was prepared at Te⁴⁺ feeding ratio of 5%. RZCT is used to fabricate high-efficiency white light-emitting diodes, and adjusting the current can realize the transition of cold and warm white light with CIE color coordinates of (0.31, 0.28) and (0.36, 0.37), respectively. It is also applied to non-contact thermometry using photoluminescence lifetime, of which maximum relative and absolute sensitivities were obtained as 0.89% and 4.76 × 10⁻³ K⁻¹, respectively. The study shows that the lead-free Te⁴⁺-doped perovskite microcrystals exist great potential in next-generation solid-state lighting and non-contact optical thermometry.