• • SCZ-4AnCN achieves a record EQE_max of 10.02% with CIE coordinates (0.154, 0.052), closely matching the BT.2020 blue standard, demonstrating the viability of anthracene-based emitters for high-efficiency deep-blue OLEDs.
• • Nondoped SCZ-4AnCN devices exhibit an EQE_max of 7.51% and maintain 6.74% EQE at 1000 cd m−2, corresponding to a mere 10% efficiency roll-off, indicating superior operational stability for practical applications.
• • The spirofluorene bridge introduces sp3-hybridized bridgehead carbons that restrict π-conjugation extension and fine-tune donor–acceptor interactions, stabilizing the S1 state with dominant LE character and suppressing intermolecular π–π stacking.
• • Sensitization experiments with 1-indanone (ET1 = 3.29 eV) and 2-acetonaphthone (ET1 = 2.58 eV) provide conclusive evidence for hRISC channels in both emitters, confirming the presence of high-lying triplet states (Tn, n≥2) above 2.58 eV that enable efficient triplet harvesting.