Progress in optical properties of chiral metal clusters: circular dichroism and circularly polarized luminescence

The design of metal cluster-based materials exhibiting exceptional circular dichroism (CD) and circularly polarized luminescence (CPL) performance has garnered significant attention due to their promising applications in 3D displays, photoelectric devices, and encrypted information storage. With the rapid advancement of metal cluster chemistry and characterization techniques, numerous atomically precise metal clusters and nanoclusters have emerged over the past two decades, providing an ideal platform for systematic investigation into the correlation between the optical properties of chiral metal clusters and their structures. The present review aims to elucidate how the regulation of chiral metal cluster structures affects their CD or CPL signals, with the ultimate objective of providing a reference for the rational design of CPL materials in the future. Specifically, the correlation of typical chiral metal clusters and their corresponding CD signals is first discussed. Subsequently, we summarize recent progress in CPL-active metal clusters and analyse their luminescence nature. Finally, we provide a summary of our findings and present the challenges and prospects in this field. This review aims to elucidate how the regulation of chiral metal cluster structures affects their circular dichroism or circularly polarized luminescence (CPL) signals, with the ultimate objective of providing a reference for the rational design of CPL materials in the future.