Three–step cascaded artificial light–harvesting systems with tunable efficiency based on metallacycles

[Display omitted] It is still challenging to develop multi–step cascaded artificial light–harvesting systems (ALHSs) with tunable efficiency. Here, we designed novel cascaded ALHSs with AIE–active metallacycles as the light–harvesting antenna, Eosin Y (ESY) and sulforhodamine 101 (SR101) as conveyors, near–infrared emissive chlorin–e6 (Ce6) as the final acceptor. The close contact and fair spectral overlap between donor and acceptor molecules at each level ensured the efficient sequential three–step energy transfer. The excited energy was sequentially and efficiently funneled to Ce6 along the cascaded line MTPEPt1 → ESY → SR101 → Ce6. Additionally, a unique strategy for regulating the efficiency of ALHS was illustrated by adjusting hydrophilic and hydrophobic interactions.