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

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/m². This work provides a new paradigm for high-performance multi-helicenes with chiral optoelectronics.