Construction of a high color-purity deep-blue emitter based on an indolo[3,2,1-jk]carbazole center using a crossed long-short axis (CLSA) molecular design strategy

Abstract

Moving 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 the molecular design strategy. Herein, the molecular design strategy of the crossed long-short axis (CLSA) is applied for the first time for the construction of indolo[3,2,1-jk]carbazole (ICz) for tuning emission color purity via the spectral narrowing effect, and the derivative CNICz-2BuCz exhibits expected optical performance with a full width at half maximum of 33 nm in solution and enhanced PLQY due to the introduction of peripheral tert-butyl modified carbazole groups. Owing to high-lying reverse intersystem crossing channels and a narrow emission characteristic, it exhibits excellent device performance with a maximum external quantum efficiency of 7.46% at CIE_y = 0.045, showcasing the great potential of the combination of the CLSA strategy and the ICz group in realizing efficient and narrow blue OLEDs.