Multiple Resonance Quasi‐fluorescence from BN‐Doped Aromatic Compounds Modified with “Naphthalene” Units Approaches the BT.2020 Green Light Standard

Abstract Developing fluorophores that conform to the Broadcast Service Television 2020 (BT.2020) standard presents a formidable challenge. Here, we propose an innovative approach that integrates two and three‐boron/nitrogen (BN2)‐embedded [4]helicene subunits with naphthalene, resulting in the synthesis of two novel narrowband bright green quasi‐fluorescent emitters, NT‐2B and NT‐3B for ultra‐high‐definition displays. These emitters exhibit minimal reorganization energy and Huang–Rhys factor, emitting at 510 and 511 nm in dilute toluene solution with exceptionally narrow full width at half maximum values of 15 and 14 nm, respectively. Notably, NT‐2B demonstrates an impressive photoluminescence quantum yield of 92.5 %, rapid radiative decay rate, and slow non‐radiative decay rate. Owing to their narrowband emission characteristics and outstanding optoelectronic properties, corresponding OLEDs based on NT‐2B demonstrate a high external quantum efficiency of 30.6 %, with an FWHM value of 21.5 nm and a CIE y of 0.74, positioning it as one of the leading narrow‐band green emitters.