Tunable Dual‐Emission in Monodispersed Sb 3+ /Mn 2+ Codoped Cs 2 NaInCl 6 Perovskite Nanocrystals through an Energy Transfer Process

Double halide perovskites are a class of promising semiconductors applied in photocatalysis, photovoltaic devices, and emitters to replace lead halide perovskites, owing to their nontoxicity and chemical stability. However, most double perovskites always exhibit low photoluminescence quantum efficiency (PLQE) due to the indirect bandgap structure or parity-forbidden transition problem, limiting their further applications. Herein, the self-trapped excitons emission of Cs2 NaInCl6 by Sb-doping, showing a blue emission with high PLQE of 84%, is improved. Further, Sb/Mn codoped Cs2 NaInCl6 nanocrystals are successfully synthesized by the hot-injection method, showing a tunable dual-emission covering the white-light spectrum. The studies of PL properties and dynamics reveal that an energy transfer process can occur between the self-trapped excitons and dopants (Mn2+ ). The work provides a new perspective to design novel lead-free double perovskites for realizing a unique white-light emission.