Highly Efficient Thermally Activated Delayed Fluorescence via an Unconjugated Donor–Acceptor System Realizing EQE of Over 30%

. The solution-processed OLEDs also display an interesting EQE of 16.2%. 3tDMG shows improved solubility and solution processability as compared to 2tDMG, and thus a high EQE of 20.2% in solution-processed OLEDs is recorded. The corresponding evaporation-processed OLEDs also reach a reasonably high EQE of 26.3%. Encouragingly, this work provides a novel strategy to address the imperious demands for OLEDs with high EQE and low roll-off.