Unity of Opposite: Highly Emissive Luminogens in both Solution and Aggregate States toward Room Temperature Phosphorescence and Electroluminescence

Abstract

Organic light-emitting materials, especially those with two-phase high emission, have attracted considerable attention for applications in bioimaging agents, sensors, optoelectronic devices, etc. Many fluorophores applied in such fields either emit brightly in dilute solution or in aggregate state, with the former often suffering from aggregation-caused quenching effect, and the latter falling dark at low concentrations. Herein, we overcame the dilemma by balancing the planar and distorted structures with various side units and achieved bright emission in both dilute solution (e.g., the absolute quantum yields (ФPL) = 90.2% in THF) and in aggregate states (e.g., ФPL=92.7% in powder state, ФPL = 95.3% in crystal). These luminescent mate-rials are demonstrated as promising guests embedded into host matrix to achieve efficient room temperature phosphores-cence, and these host-guest systems could be applied in the information encryption. Moreover, these luminogens could also be used as single-component emitting layers to construct non-doped organic light-emitting diodes, from which a maximum external quantum efficiency up to 4.75% with Commission International de L’Eclairge (CIE) coordinates of (0.15, 0.05), which is neatest to next generation ultra-high definition television (UHDTV) display standard, was realized. This work pro-vides a feasible strategy of balancing the planar and distorted structure of a luminogen toward highly efficient emission in both solution and solid states.