Boosting green luminescence in zero-dimensional K3InCl6 via Ce3+/Sb3+ co-doping and energy transfer

Zero-dimensional (0D) perovskites have emerged as a promising class of luminescent materials due to their strong carrier confinement and efficient self-trapped exciton (STE) emission. However, achieving high emission efficiency and tailored photoluminescence (PL) through rational dopant engineering remains a challenge. In this work, we demonstrate the successful synthesis of phase-pure, 0D Ce 3+ /Sb 3+ co-doped K 3 InCl 6 microcrystals, which retain the intrinsic [InCl 6 ] 3- octahedral structure. We unveil the distinct yet synergistic roles of the co-dopants: Sb 3+ acts not only as an efficient STE emitter but also as a structural modulator, while Ce 3+ functions as an effective ultraviolet (UV) absorber and energy sensitizer. Crucially, we observe anti-correlated changes in the exciton binding energies upon co-doping: a decrease for Ce 3+ and a significant increase for Sb 3+ . This compelling evidence directly confirms the occurrence of efficient energy transfer from Ce 3+ to Sb 3+ , which is further supported by the concomitant suppression of Ce 3+ emission and a remarkable enhancement of the characteristic Sb 3+ green emission centered at 520 nm. By optimizing the dopant synergy effect, we achieve a substantial boost in the overall green luminescence. This work not only provides fundamental insights into the dopant interactions and energy transfer mechanisms within 0D perovskite systems but also establishes a practical and effective strategy for the development of novel and high-performance luminescent metal halide perovskite materials.