Efficient Deep-Blue Electrofluorescence with an External Quantum Efficiency Beyond 10%

The design of blue fluorescent materials combining both deep-blue emission (CIE(y)<0.06) and high-efficiency climbing over the typically limited exciton production efficiency of 25% is a challenge for organic light-emitting diodes (OLEDs). In this work, we have synthesized two blue luminogens, trans-9,10-bis(2-butoxyphenyl)anthracene (BBPA) and trans-9,10-bis (2,4-dimethoxyphenyl)anthracene with high photoluminescence quantum yields (PLQYs) of 89.5% and 87.0%, respectively. Intriguingly, we have proposed a strategy to avoid aggregation-caused quenching, which can effectively reduce the undesirable excimeric emission by introducing two host matrices with twisted molecular structure, 9,10-di(naphth-2-yl) anthracene and 10,10′-bis-(4-fluorophenyl)-3,3′-dimethyl-9,9′-bianthracene (MBAn-(4)-F), in the BBPA emission layer. The device containing the EML of BBPA-doped MBAn-(4)-F exhibited a high external quantum efficiency of 10.27% for deep-blue emission with the Commission International de L'Eclairage CIE coordinates of (0.15, 0.05) via the steric effect. Importantly, this represents an advance in deep-blue-emitting fluorescent OLED architectures and materials that meet the requirements of high-definition display.