Highly Emissive Luminogens in Both Solution and Aggregate States

Organic light-emitting materials have attracted considerable attention because of their promising applications in diverse areas. Most fluorophores emit brightly in either dilute solutions or aggregate states; the former generally suffer from aggregation-caused quenching problem, and the latter encounter intensity loss at low concentrations. Herein, we propose a new strategy to overcome these dilemmas by balancing the planar and distorted structures of terphenyl-based luminogens and obtain three luminogens, 2PB-AC, 2Me2PB-AC, and 2T2PB-AC, with bright emission in both solution and aggregate states. Among them, 2PB-AC shows absolute photoluminescence quantum yields (ФPL) higher than 90% in both tetrahydrofuran solution (90.2%) and aggregate states (92.7% for powder and 95.3% for crystal). Thus, 2PB-AC could be an efficient probe to realize dual-channel explosive detection in both solution and aggregate states. Moreover, it could be used to image live-cell lipid droplets at a wide range of concentrations. In addition, benefiting from its thermodynamically favorable intersystem crossing process, 2Me2PB-AC could be doped in polymethyl methacrylate matrix to provide efficient room-temperature phosphorescence. Thus, this work provides a feasible strategy for the design of luminogens with highly efficient emission in both solution and aggregate states, greatly facilitating and broadening their practical applications. © 2023 The Author(s).