Modulation of the Excitation States in All-Inorganic Halide Perovskites via Sb 3+ and Bi 3+ Codoping.

Sb ³⁺ -doped halide perovskites are promising candidates for solid-state lighting due to their diverse fluorescent colors and high efficiency. However, the mismatched high excitation energy with commercial UV chips is one of the critical issues to be addressed. Herein, a Bi ³⁺ codoping strategy was established as a general and efficient approach to modulate the excitation spectrum from the Sb ³⁺ -doping center in all-inorganic perovskites of Cs ₂ InCl ₅ ·H ₂ O, Cs ₂ NaInCl ₆ , and Rb ₃ InCl ₆ . The incorporated Bi ³⁺ greatly enhanced the splitting of the A band ( ¹ S ₀ - ³ P ₁ transition) and boosts the enormous redshift of the low-energy branch in all these systems. The interactions persist strongly even at extremely low doping concentrations, suggesting a dipole-based long-range interaction. The results provide an in-depth insight into the contribution mechanism of Bi ³⁺ to Sb ³⁺ in all-inorganic perovskites, which throws light upon tuning the excitation spectrum of broadband emission from the extrinsic self-trapped exciton (STE).