Suppressing triplet exciton quenching by regulating the triplet energy of crosslinkable hole transport materials for efficient solution-processed TADF OLEDs

Crosslinkable hole transport materials (HTMs) with high triplet energies would have a balance of carrier injection into the emitting material layer, suppressing exciton quenching and resulting in high-performance solution-processed organic light-emitting diode (OLED) devices. Two novel crosslinkable HTMs different central units, N2, N8-di-p-tolyl-N2,N8-bis(4-vinylphenyl)dibenzo[b,d]thiophene-2,8-diamine (V-p-DBT) N2,N8-di-p-tolyl-N2,N8-bis(4-vinylphenyl)dibenzo[b,d]furan-2,8-diamine (V-p-DBF), were designed synthesized. The use dibenzothiophene dibenzofuran units increases torsion angle compared commonly used N, N?-di-p-tolyl-N, N?-bis(4-vinylphenyl)-[1,1?-biphenyl]-4,4?-diamine (V-p-TPD), leading to 2.57 2.64 eV, respectively. V-p-DBT V-p-DBF effectively suppress quenching. Furthermore, crosslinked HTM layer showed excellent solvent-resistant abilities thermal stability. An outstanding maximum current efficiency (CEmax) 79.94 cd A?1 external quantum (EQEmax) 24.35% obtained by V-p-DBF-based green thermally activated delayed fluorescent (TADF) OLEDs. This work provides new molecular design strategy for achieving efficient TADF