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

Abstract

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 (|g_lum|) of 1 × 10^-2. Notably, the CPL signals of R/S-Ag₆ are further distinctly amplified with |g_lum| 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 Ag_xCu_6-x alloy clusters, ultimately resulting in near-infrared CPL with |g_lum| 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.