Chiral metal cluster-mediated chirality transfer in light-harvesting nanoribbons for amplified circularly polarized luminescence

The construction of artificial light-harvesting systems (LHSs) with continuous chirality transfer is of great significance to deeply comprehend the hierarchical evolution in nature. Herein, the achiral C3-symmetric benzene-1,3,5-tricarboxamide (BTA) molecule functions as donor of LHSs motifs, where subnanometer-scale metal clusters (R/S-Ag6) are introduced as “Sergeants” to generate predominant handedness nanoribbons through chirality transfer. Importantly, these helical nanoribbons act as chirality and energy donors for the energy level-matching Ag6-cluster acceptors, enabling the fabrication of chirality-controlled LHSs that achieve amplified circularly polarized luminescence (CPL) of Ag6 clusters with a dissymmetry factor (|glum|) of 1 × 10-2. Notably, the CPL signals of R/S-Ag6 are further distinctly amplified with |glum| reaching 6 × 10-2 through chirality-matching and synergistic effect of R/S-1-phenylethanol. Furthermore, R/S-Cu6 clusters with near-infrared emission are employed as the second acceptor to construct relayed homochiral LHSs. Such LHSs program continuous chirality and energy transfers from BTA assemblies to Ag6 and then to AgxCu6-x alloy clusters, ultimately resulting in near-infrared CPL with |glum| of 5 × 10-2. This work provides valuable insight into the mechanisms of CPL transmission and amplification in cluster-driven chiral LHSs and opens potential application in chiroptical encryption. Light harvesting systems (LHSs) capable of continuous chirality transfer can offer insight into natural structures, but are challenging to construct. Here, the authors use metal clusters as chiral “Sergeants” to achieve continuous chirality/energy transfer, which amplifies CPL within chiral LHSs.