Pressure-Engineered Photoluminescence Tuning in Zero-Dimensional Lead Bromide Trimer Clusters

Zero-dimensional (0D) hybrid metal halides are promising light emitters. However, it is still challenging to accurately design their structures with targeted photoluminescence properties. Herein, high pressure is used to change the self-trapped exciton (STE) emission of 0D (bmpy)[ZnBr][PbBr] (bmpy: 1-butyl-1-methylpyrrolidinium). Under initial compression, the simultaneous contraction and distortion of photoactive [PbBr] vary the equilibrium of STE emissions between different excited states, tuning the emission color from yellow green to cyan. Notably, sufficient structural distortion under continuous compression leads to the formation of more and deeper STE states, exhibiting an unprecedented broadband white-light emission. This study reveals the structure-dependent optical properties of 0D hybrid metal halides, providing novel insights into the mechanism of STE emission.