Stable Broadband Bright Green Emission of Self-trapped Excitons Triggered by Sb3+ Doping in Zero-Dimensional Cs3BiCl6

Graphical In this article, all inorganic Cs 3 BiCl 6 perovskite single crystals with a 0D structure have been synthesized by the anti-solvent crystallization method. There is no obvious photoluminescence (PL) phenomenon for Cs 3 BiCl 6 at room temperature (RT) under ultraviolet light. Subsequently, we introduced Sb 3+ into Cs 3 BiCl 6 to obtain Cs 3 BiCl 6 : Sb, of which the Stokes shift is 175 nm, and full-width-at-half-maxima (FWHM) is 132 nm. By adjusting the doping concentration of Sb 3+ , the PL quantum yield (PLQY) of Cs 3 BiCl 6 : Sb was increased to 15.85 %, which has a microsecond PL lifetime and good environmental stability. Through a series of tests and characterization, we determined that the broadband emission of Cs 3 BiCl 6 : Sb originated from self-trapped exciton emission (STEs). Low-dimensional lead-based metal halide perovskites (MHPs) have many exceptional photoelectric capabilities thanks to the 6 s 2 electron structure of lead ion (Pb 2+ ). Pb 2+ ′s toxicity, however, has prevented its widespread development and use. Finding ions in the valence layer that have a comparable electrical structure thus makes sense as Pb 2+ replacements. In this work, all inorganic zero-dimensional (0D) Cs 3 BiCl 6 single crystal was synthesized by the anti-solvent crystallization method. There is no obvious photoluminescence (PL) phenomenon for Cs 3 BiCl 6 at room temperature (RT). It is found that the extremely strong exciton-phonon interaction leads to seriously non-radiative recombination. After doping with Sb 3+ , Cs 3 BiCl 6 : Sb achieved broadband emission with a significant Stokes shift, the photoluminescence quantum yield (PLQY) up to 15.85 %, which has a microsecond PL decay lifetime and excellent environmental stability. Systematic spectroscopic characterizations unveil the PL mechanism of Cs 3 BiCl 6 : Sb is self-trapped excitons (STEs) emission, and theoretical calculation revealed the indirect bandgap properties of Cs 3 BiCl 6 and Cs 3 BiCl 6 : Sb.