利用联苯扭曲骨架实现电子解耦的蓝光双极主体材料OA

Addressing the persistent challenge in blue phosphorescent devices of balancing high triplet energy lev-els with balanced charge carrier transport in host materials,this study proposes a novel"spatial hindrance-induced electronic decoupling"strategy.By constructing D-A-type host materials(N,N-diphenyl-2′-tosyl-[1,1′-biphenyl]-2-amine/N,N-di-p-tolyl-2′-tosyl-[1,1′-biphenyl]-2-amine)with multiple twisted conformations via the 2,2′-position of a biphenyl skeleton,a synergistic combination of a high triplet energy level(2.66 eV)and bipolar charge trans-port properties was successfully achieved.Theoretical calculations and experimental characterizations confirm that spatial hindrance effectively suppresses electronic coupling between the donor and acceptor units,maintaining a high-energy structure dominated by localized excited states.Device performance validated the advantages of this strategy in exciton confinement and charge carrier balance,while also revealing limitations in efficiency due to molec-ular conformational dynamic instability.This study identifies the dynamic conformational stability of molecules as a critical constraint on device efficiency in steric-hindrance-based blue host materials,thus providing a clear design principle for performance breakthrough through enhanced structural rigidity.