Near-unity photoluminescence quantum yield in zero-dimensional lead-free indium-based hybrid perovskites by antimony doping

Lead-free zero-dimensional (0D) hybrid halide perovskites have recently attracted considerable attention due to their outstanding photophysical properties. Although broadband emission can be obtained in metal halide perovskites, the realization of highly efficient light emission with a near-unity photoluminescence quantum yield (PLQY) remains extremely challenging. In this study, lead-free (C4H12N)2InCl5 center dot DMF (DMF = HCON(CH3)2) crystals with a 0D structure were investigated as a pristine compound to design novel luminescent materials, which enables broadband yellow emission with high PLQY up to 99.3% via Sb3+-doping. Steady-/transient-state spectral analysis reveals that the broadband emission originates from self-trapped excitons of the Sb3+ luminescent center. High PLQY and excellent environmental stability pave the way for its further applications in light-emitting diodes. The results provide fundamental insight into the efficient light emission of Sb3+ in hybrid metal halides and offer guidance for the design of promising luminescent materials for optoelectronic applications. High-performance broadband emission with a near-unity photoluminescence quantum yield of similar to 99.3% was observed in (C4H12N)2InC5 center dot DMF:Sb3+ hybrid perovskites, which can be attributed to the self-trapped excitons of the [SbCl5 center dot DMF]2- polyhedron.