Abstract Simultaneously achieving high efficiency, high color purity, and low efficiency roll‐off remains a critical challenge in deep‐blue organic light‐emitting diodes (OLEDs). Herein, we strategically synthesize two novel rigid tetradentate Pt(II) emitters incorporated with a new polycyclic aromatic hydrocarbon molecular skeleton, 7,12‐dihydro‐5 H ‐7,12‐1,2benzenonaphtho2,3‐ b carbazole (BNCz) (PtJY1 and PtJY2). A three‐dimensional triptycene group is firstly merged into the carbazole ligand, together with bulky steric substituents in the benzocarbene unit, to synergistically suppress inter‐ and intramolecular interactions, enhance molecular rigidity, and modulate excited‐state properties. PtJY1 and PtJY2 exhibit ultra‐narrow deep‐blue emission in toluene at room temperature, with peaks at 461.8 and 464.2 nm and full‐width at half‐maximum (FWHM) values of 16.6 and 15.1 nm, respectively. High photoluminescence quantum yields (Φ PL ) of 95% and 99% are achieved in doped host films. Corresponding deep‐blue OLEDs achieve maximum external quantum efficiencies (EQE max ) of 29.3% and 31.2%, with Commission Internationale de l’Éclairage (CIE) y of 0.133 and small FWHM values of 21 and 19 nm, respectively. At 1000 cd/m 2 , the EQEs are retained at 27.0% and 27.8%, exhibiting extremely low efficiency roll‐off. Notably, the device performance of PtJY2 ranks among the best‐balanced Pt(II)‐ and Ir(III)‐based blue phosphorescent OLEDs with CIE y < 0.15. This work provides a valuable strategy for developing highly efficient, narrow‐spectrum deep‐blue tetradentate Pt(II) emitters for optimal performance in OLED applications.
Lin et al. (2025) studied this question.