Blue organic light-emitting diodes with hybridized local and charge-transfer excited state realizing high external...

Donor-spacer-acceptor (D-π-A) materials CAPI and CCAPI, with hybridized local and charge transfer (HLCT) emissive states, have been synthesized. The twisting D-π-A architecture promotes the partial separation of HOMO and LUMO, leading to an enhanced % CT component, and the anthracene moiety in CAPI and CCAPI increases the conjugation length, leading to an enhanced % LE component. The non-doped device with CCAPI^b shows the blue emission (450 nm) with maximum current efficiency (η _c), power efficiency (η _p), and external quantum efficiency (η _ex) of 16.83 cd A^-1, 15.32 lm W^-1, and 12.0%, respectively, as well as exciton utilization efficiency (EUE) of 95% with a luminance of 32 546 cd m^-2 and a roll-off efficiency of 0.53%. The new design strategy has great potential for developing high-performance blue electroluminescent materials.