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.