Three-step sequential artificial light-harvesting systems constructed by tetraphenylethylene macrocycle-based supramolecular cascade assembly in water for tunable photoluminescence

A novel artificial light-harvesting system (LHS) with three-step sequential energy transfer in water was successfully fabricated based on supramolecular cascade assembly. Specifically, the BINOL derivative (BDA) could self-assemble into nanoparticles serving as an energy donor, TPE-based macrocycle (TPEA) with AIE characteristic, acted as a relay acceptor that could transfer excitation energy to the Nile Red (NIR) and a near-infrared AIEgen (TPESe). Owing to the flexibility of supramolecular strategy and good spectra overlap of donor and acceptors, the system of BDA/TPEA/NIR/TPESe could occur three-step sequential energy transfer from BDA to TPEA to NIR to TPESe with high energy-transfer efficiencies. By properly tuning the ratio between the donor and acceptors, bright white light emission can be successfully achieved with a CIE value of (0.32, 0.33) or (0.33, 0.34). Finally, the LHS nanoparticles were applied to LED devices to achieve color-tunable photoluminescence. Therefore, the flexibility feature of supramolecular strategy positions the AIEgen based-macrocycle as a highly promising candidate to construct efficient LHSs for manufacturing bright organic luminescent materials.