An efficient hierarchical self-assembly approach to construct structurally diverse two-step sequential energy-transfer artificial light-harvesting systems

Efficiently fabricating artificial light-harvesting systems (LHSs) with cascade energy transfer properties is significant for mimicking natural photosynthesis. Through a coordination-driven self-assembly approach, metallacycle M surrounded by alkyl chains was successfully constructed from tetraphenylethylene (TPE) building blocks in nearly quantitative yield. Interestingly, from the prepared metallacycle M, star-shaped supramolecular complex M-3 and cross-linked supramolecular network M-4 with one-step energy-transfer properties were efficiently fabricated based on host-guest interactions. Furthermore, from M-3 and M-4, two different artificial light-harvesting systems (LHSs) with two-step sequential energy transfer characteristics were efficiently prepared via supramolecular interactions. The two types of LHSs were compared in detail, and the critical factors affecting the light-harvesting efficiency, including the photophysical properties, aggregation-induced emission characteristics, energy transfer efficiency, and antenna effect, were carefully analysed. Additionally, both of the artificial LHSs, M-3-5 and M-4-5, showed excellent energy transfer efficiency and high antenna effects. This research provides an efficient hierarchical self-assembly approach to construct artificial LHSs featuring excellent energy transfer efficiency and high antenna effects with diverse architectures.