Asymmetric anthracene hosts decorated with naphthobenzofurocarbazole for highly efficient deep-blue organic light-emitting diodes and low-efficiency roll-off

Abstract

Two fluorophores, 5-(4-(10-phenylanthracen-9-yl)phenyl)-5H-naphtho[2',3':4,5]furo[3,2-c]carbazole (ATPNF-1) and 5-(3-(10-phenylanthracen-9-yl)phenyl)-5H-naphtho[2',3':4,5]furo[3,2-c]carbazole (ATPNF-2), were synthesized by incorporating a naphthobenzofurocarbazole unit in different positions of the anthracene core. The fluorophores functioned as deep-blue fluorescent emitters and host materials for the t-DABNA dopant. ATPNF-1 predominantly exhibited a hybrid local and charge-transfer (HLCT) emission, with a minor contribution from the triplet-triplet fusion (TTF) channel. The non-doped organic light-emitting diode (OLED) device exhibited emission in the National Television System Committee standard blue color, with a narrow full width at half maximum of 54 nm and a maximum external quantum efficiency (EQE) of 7.0%, along with suppressed efficiency roll-off (an efficiency roll-off value of 4.8% at 1000 cd m(-2)). The t-DABNA-based device achieved a maximum EQE of 8.0% and a low-efficiency roll-off, demonstrating its highly efficient performance for deep-blue fluorescent OLEDs. These results can be attributed to the TTF-mediated high-lying reverse intersystem crossing process, highlighting the potential of such a blue-material design strategy for developing efficient OLED devices.