Highly Efficient Narrowband Circularly Polarized Luminescence from Discrete Supramolecular Aggregates

Achieving narrowband emission, high efficiency, and circularly polarized luminescence (CPL) in organic light-emitting diodes (OLEDs) remains a significant challenge. In this study, a discrete supramolecular dimerization strategy is presented to overcome this limitation. By incorporating a helical arylamine with a sterically demanding configuration into a multi-resonance narrowband emitter, the formation of a unique dimeric structure in the solid state is enabled. Unlike conventional multi-resonance emitters prone to aggregation-caused quenching and continuous stacking, the CPL emitters form discrete, well-separated dimers. This distinct supramolecular arrangement not only preserves high photoluminescence quantum yield and narrowband emission but also amplifies CPL signals by optimizing intermolecular electronic coupling. OLEDs incorporating these enantiomers at a 10 wt.% doping level exhibit outstanding performances, including a narrow full-width at half-maximum of 30 nm, maximum external quantum efficiencies (EQE) of 33.5% and 32.4%, and impressive electroluminescence dissymmetry factors (g_EL) of +8.7 × 10^-3 and -9.1 × 10^-3, respectively. Remarkably, increasing the doping concentration to 20 wt.% further boosts the g_EL values to +1.6 × 10^-2 and -1.8 × 10^-2. This enhancement leads to Figures of Merit (EQE × |g_EL|) of 3.71 × 10^-3 and 4.12 × 10^-3, among the highest values for CPL devices.