A General Design Principle for Aggregation-Induced Room-Temperature Phosphorescence via An sp3-Linked Donor-Acceptor Structure

Intramolecular motion is commonly more detrimental to room-temperature phosphorescence (RTP) than to prompt fluorescence because long-lived triplet excitons offer more possibilities of quenching. Inspired by the mechanism of aggregation-induced emission (AIE), a single molecule is endowed with AIE and RTP features at the same time. By utilizing triphenylamine (TPA) as AIE activator as well as electron donor and an sp³ linkers as a bridge between donor and acceptor, five TPA-based AIE-active RTP luminophores were designed. RTP and low-temperature emissions reveal the co-existence of ternary emission, including fluorescence and dual phosphorescence. Single-crystal analyses and theoretical calculations suggest dual phosphorescence derives from local excitation and charge-transfer component. By utilizing hot exciton emission, color-tunable phosphorescence can act as an indicator for temperature estimation. This combinatory approach pioneers a new route for designing versatile AIE-active RTP materials.