Abstract Narrowband red emission remains a long-sought target for organic light-emitting diodes (OLEDs), but has proven exceptionally difficult to realize using polycyclic aromatic hydrocarbons (PAHs). Herein, we introduce a general molecular design paradigm that harnesses π-electron reorganization through skeletal reconstruction in PAHs. This topological engineering localizes aromaticity into discrete segments, intrinsically suppressing vibronic coupling and yielding exceptionally narrowband emission. Using ovalene as a model system, we created a family of PAH-based fluorophores spanning yellow to deep red (559−670 nm) with exceptionally narrow full-width at half-maximum (FWHM) values of 18−24 nm. When integrated into sensitized OLEDs, these emitters deliver record-setting device performance. A representative compound produces sharp red emission at 639 nm with a FWHM of only 28 nm/ 0.085 eV, Commission Internationale de l’Éclairage (CIE) coordinates of 0.704, 0.294 that precisely match the BT.2020 red standard (0.708, 0.292), and an external quantum efficiency exceeding 24%—the highest reported value for traditional red fluorescent systems. To our knowledge, this constitutes the first demonstration of a BT.2020-compliant red emitter with FWHM below 30 nm.
Li et al. (Thu,) studied this question.