Inverted and Amplified CP‐EL Behavior Promoted by AIE‐Active Chiral Co‐Assembled Helical Nanofibers

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).