Wide-Range Color-Tunable Narrowband Fluorescence Emitters Based on 1,2-BN-Embedded Polycyclic Aromatic Hydrocarbons

Developing a generalizable design principle that reconciles wide-range color tunability with intrinsically narrowband emission in polycyclic aromatic hydrocarbons (PAHs) remains a fundamental challenge in molecular optoelectronics. Herein, we combine the aromatic localization effect (ALE) with heteroatomic topology engineering to establish a versatile 1,2-BN-fluoranthene embedding strategy, implemented through a concise carbazole-assisted borylation. This approach furnishes a modular family of [B-N]₂PAHs whose emissions span the visible-to-near-infrared range (429-703 nm) while retaining exceptionally narrow full widths at half maximum (FWHM) down to 14 nm. Their chromaticities satisfy the stringent BT.2020 display standard, with selected derivatives even reaching the ultra-high-purity ProPhoto RGB gamut, establishing a viable platform for wide-color-gamut OLEDs. Representative pyrene- and perylene-based [B-N]₂PAHs display near-unity photoluminescence quantum yields (up to 99%) and ultrahigh horizontal transition dipole ratios (up to 98.0%), enabling outstanding electroluminescence performance. Devices based on these emitters exhibit emission peaks at 481 and 542 nm with narrow FWHMs of 19 and 29 nm, respectively and achieve maximum external quantum efficiencies (EQE_max) of 35.5% and 44.3%-the first fluorescent OLEDs to surpass the 40% EQE threshold. Importantly, 1,2-BN-embedded PAHs rival state-of-the-art 1,4-BN-based multiple-resonance (MR) emitters, while offering a substantially simpler, more general synthetic blueprint readily extendable to diverse PAH architectures.