Synthesis and properties of naphthalimide derivative functionalized N,N′-bicarbazole for complementary white light-emitting diodes with exciplex

1,8-naphthalimide (NI) derivatives are custom-modified specifically as emitting layers in organic light-emitting devices (OLEDs) to realize full-color emission and improve the lifetime and luminous stability. In this work, a multifunctional cruciate-type blue emitter BCz-NI based on N-buthyl-1,8-naphthalimide linked with the N,N′-bicarbazole donor group was designed and synthesized with D-A structured. The emitter BCz-NI shows hybridized local and charge-transfer state characteristics to make full use of the formed excitons and reduce losing energy, which is attributed to the cruciate-type core providing efficient steric hindrance to promotes energy transfer. The non-doped OLEDs based on BCz-NI as a blue light material to achieve warm white light emission with commission internationale de leclairage coordinates of (0.41, 0.37) by combining the blue light material and the exciplex generated with the electron transport layer. This research would provide theoretical basis for complementary white light OLED by forming exciplex.