• • OD-CQRs achieve pure-violet emission at 393 nm with an FWHM of only 18 nm and PLQY of 95%, setting a new benchmark for carbon-based emitters; this combination enables high colour purity and efficiency for next-generation displays.
• • Synthesis via one-step solid-state reaction at 180 °C between 2,3-dihydroxynaphthalene and anhydrous SnCl2 offers a scalable, low-cost alternative to complex multistep organic syntheses, reducing production barriers.
• • The O-π confinement strategy, introducing alternating oxygen heterocycles, restricts π-electron delocalization and suppresses non-radiative relaxation, as evidenced by near-zero root mean square displacement (0.0 Å) between ground and excited states, ensuring minimal energy loss.
• • STM imaging at 4.7 K confirms a planar hexagonal ring structure with diameter 18.8 Å, matching DFT predictions, and ordered honeycomb monolayers on Au(111) stabilized by weak O···H hydrogen bonds, indicating potential for thin-film device integration.