Facilely Enantiopurified Novel Double Aza[7]Helicenes for Extremely Narrowband Circularly Polarized Luminescence

Abstract

Abstract Multi‐resonance multi‐helicenes are promising for efficient narrowband emission and chiroptical properties, yet systems based predominantly on boron–nitrogen frameworks often exhibit broadened spectra. Here, we present a brand‐new double aza[7]helicene built on a nitrogen‐containing indolocarbazole scaffold, incorporating four consecutive para‐positioned nitrogen atoms arranged through alternating fusion of five‐ and six‐membered rings. This tailored structure enhances the multi‐resonance effect, enabling pure‐green emission with a narrow full‐width at half‐maximum of 18 nm, a photoluminescence quantum yield of 90%, and a chromaticity y‐coordinate of 0.70, while also stabilizing the double helix configuration. The enantiomers are readily separated using conventional thin‐layer chromatography, avoiding costly chiral columns, and show strong circularly polarized luminescence with dissymmetry factors of 3.3 × 10 −3 . The corresponding organic light‐emitting diodes achieve high‐color‐purity green electroluminescence, with a maximum external quantum efficiency of 30.2%, maintaining > 20% at 100,000 cd/m 2 . This work provides a new paradigm for high‐performance multi‐helicenes with chiral optoelectronics.