Inverted and Amplified CP‐EL Behavior Promoted by AIE‐Active Chiral Co‐Assembled Helical Nanofibers
Zhongxing Geng, Zheng Liu, Hang Li, Yu Zhang, Wen‐Hua Zheng, Yiwu Quan, Yixiang Cheng
Abstract
Abstract It is well‐known that high‐performance circularly polarized organic light‐emitting diodes (CP‐OLEDs) remain a formidable challenge to the future application of circularly polarized luminescent (CPL)‐active materials. Herein, the design of a pair of AIE‐active chiral enantiomers ( L/D ‐HP) is described to construct chiral co‐assemblies with an achiral naphthalimide dye (NTi). The resulting co‐assemblies emit an inverted CPL signal compared with that from the L/D ‐HP enantiomers. After thermal annealing at 120 °C, the inverted CPL signal of this kind of L/D ‐HP‐NTi with a 1:1 molar ratio shows regular and ordered helical nanofibers arranged through intermolecularly ordered layered packing and is accompanied with a further amplified effect (| g em | = 0.032, λ em = 535 nm). Significantly, non‐doped CP‐OLEDs based on a device emitting layer (EML) of L/D ‐HP‐NTi exhibits a low turn‐on voltage ( V on ) of 4.7 V, a high maximum brightness ( L max ) of 2001 cd m −2 , and moderate maximum external quantum efficiency ( EQE max ) of 2.3%, as well as excellent circularly polarized electroluminescence (CP‐EL) (| g EL | = 0.023, λ em = 533 nm).