Zero-Thermal-Quenching Layered Metal Halide Perovskite

In the quest for new functional materials, Mn2+-activated metal halide perovskites (MHPs) were found to possess remarkable optical properties. However, they show low photoluminescence quantum yield (PLQY) and weak thermal stability. This is due to weak dopant–host interactions and strong phonon–lattice coupling at high temperatures of MHPs. Developing Mn2+-activated MHPs with a high PLQY and good thermal stability has become a highly versatile research area to meet current needs. Herein, we synthesized Mn2+ ion-activated Rb3(Cd1–x Mn x )2Cl7 layered metal halide perovskite (LMHP) and solved its crystal structure using direct methods. The Rb3(Cd1–x Mn x )2Cl7 LMHP exhibits an orange emission with a high PLQY of 88%, the highest among Mn2+-activated MHPs. Moreover, Rb3(Cd0.80Mn0.20)2Cl7 exhibits a zero-thermal-quenching (TQ) behavior, which is considered the first for the MHP family. Therefore, our results could pave the way for a search for new LMHPs with zero-TQ behavior for high-power optoelectronic applications.