Creation of High‐Quality Deep‐Blue AIE Emitter with a Crossed Long‐Short Axis Structure for Efficient and Versatile OLEDs

Abstract Developing deep‐blue emitters for organic light‐emitting diodes (OLEDs) is critical but challenging, which requires a good balance between light color, exciton utilization, and photoluminescence quantum yield (PLQY) of solid film. Herein, a high‐quality deep‐blue emitter, abbreviated 2TriPE‐CzMCN, is designed by introducing an aggregation‐induced emission (AIE) group into a crossed long‐short axis (CLSA) skeleton. Theoretical and experimental investigations reveal that the CLSA molecular design can achieve a balance between deep‐blue emission and triplet‐excitons utilization, while the high PLQY of the solid film resulting from the AIE feature helps to improve the performance of OLEDs. Consequently, when 2TriPE‐CzMCN is used as the emitting dopant, the OLED exhibits a deep‐blue emission at 430 nm with a record‐high maximum external quantum efficiency (EQE) of 8.84%. When 2TriPE‐CzMCN serves as the host material, the sensitized monochrome orange and two‐color white OLEDs (WOLEDs) realize high EL performances that exceed the efficiency limit of conventional fluorescent OLEDs. Moreover, high‐performance three‐color WOLEDs with a color rendering index (CRI) exceeding 90 and EQE up to 18.08% are achieved by using 2TriPE‐CzMCN as the blue‐emitting source. This work demonstrates that endowing CLSA molecule with AIE feature is an effective strategy for developing high‐quality deep‐blue emitters, and high‐performance versatile OLEDs can be realized through rational device engineering.