Construction of High Color-Purity Deep-blue Emitter Based on Indolo[3,2,1-jk]carbazole Center from Crossed Long-Short Axis (CLSA) Molecular Design Strategy

Abstract

Marching toward next-generation ultrahigh-definition and high-resolution displays, the development of high-performance blue organic light-emitting diodes (OLEDs) with emission matching the BT.2020 standard is essential and requires advancements in molecular design strategy. Here, the molecular design strategy of crossed long-short axis (CLSA) is applied firstly in a new construction core of indolo[3,2,1-jk]carbazole (ICz) for tuning emission color purity via spectra narrowed effect, whose derivative named CNICz-2BuCz has expected optical performance with full width at half maxima of 33 nm in solution and enhanced PLQY from the introduction of peripheral tert-butyl modified carbazole groups. Thanks for high-lying reverse intersystem crossing channels and narrow emission characteristic, its device performance is excellent with maximum external quantum efficiency of 7.46% at CIEy=0.045, which showcases the great potential of the combination of CLSA strategy and ICz group in realizing efficient and narrow blue OLEDs.