Dual role of novel hole-transporting and deep-blue emitting materials based on twisted binaphthyl

Abstract

Three novel deep blue-emitting materials from binaphthyl derivatives, namely BFS, BNS and BNF, were designed and synthesized. Due to their rigid structure, all the materials exhibit high thermal stability with Td exceed 440 °C and Tg as high as 153 °C, 149 °C and 140 °C, respectively. They also show appropriate HOMO and LUMO energy level, excellent amorphous stability and outstanding solubility in common organic solvents. These novel materials are highly emissive in both solution and solid states, with deep blue emissions peaked at ∼450 nm. Deep-blue OLEDs using the novel materials as emitter resulted in efficient CE, EQE and luminance. The BFS, BNS and BNF based devices show good EL performances with the Lmax of 857 cd/m2 (CEmax of 0.3 cd/A), Lmax of 1038 cd/m2 (CEmax of 0.5 cd/A), and Lmax of 3717 cd/m2 (CEmax of 0.5 cd/A), respectively. They should be promising hole-transport and deep blue-emitting materials for OLED devices.