Efficient Energy Transfer in Te⁴⁺-Doped Cs₂ZrCl₆ Vacancy-Ordered Perovskites and Ultrahigh Moisture Stability via A-Site Rb-Alloying Strategy

Abstract

As an effective method to improve the optical properties and stability of perovskite matrix, doped halide perovskites have attracted extensive attention in the field of optoelectronic applications. Herein, a series of all inorganic lead-free Te⁴⁺-doped Cs₂ZrCl₆ vacancy-ordered perovskites were successfully synthesized with different Te-doping concentrations by a solvothermal method, and deliberate Te⁴⁺-doping results in green-yellow triplet self-trapped exciton (STE) emission with a high photoluminescence quantum yield (PLQY) of 49.0%. The efficient energy transfer was observed from singlet to triplet emission. Further, the effects of A-site Rb alloying on the optical properties and stability were investigated. We found that A-site Rb alloying and C-site cohalogenation did not change the luminescence properties of Te⁴⁺, but the addition of a small amount of Rb⁺ can improve the PL intensity and moisture stability. Our results provide physical insights into the <i>n</i>S² Te⁴⁺-ion-doping-induced emissive mechanism and shed light on improving the environmental stability for further applications.