Exploration of High Efficiency AIE-Active Deep/Near-Infrared Red Emitters in OLEDs with High-Radiance

摘要

Limiting by classic donor-acceptor (D-A) strategy based on charge transfer (CT) process dominated emission, the high-efficiency organic deepear infrared red (DR/NIR) emitters with desirable photoluminescence quantum yields (PLQYs) and satisfactory excitons utilization efficiencies (EUEs) are still a challenge. Herein, three new DR/NIR luminogens (TNZPPI, TNZtPPI and TNZ2tPPI) based on naphtho[2,3-c][1,2,5]thiadiazole (NZ) group are synthesized. Their interesting characterization of hybrid excited states containing tuned local excited (LE) and CT components are confirmed, and the effective high-lying reverse intersystem crossing (RISC) channel might be activated because of their larger T-2-T-1 energy gap and smaller T-4-S-2 energy splitting. Thanks for their higher fluorescence quantum yields in film (24-38%), the TNZPs-based non-doped devices exhibit bright NIR emission with higher maximum radiance of 21447-36027 mW Sr-1 m(-2), whose performance are better than most reported pure organic NIR devices. Enjoying deep analysis of their solvation effect and aggregation-induced emission (AIE)-activity, the doped organic light emitting diodes (OLEDs) are fabricated, whose performances are very good with identical National Television System Committee saturated red-emitting behaviors. The results in TNZPs show that the electronic effect of molecule structure and intermolecular interactions all are relative to their performance, and which is very important for the design high-efficiency NZ-based OLED materials.