Precise Modulation of Sterically Shielded Pt (II) Complex for Deep Blue OLED Enabled Long Lifetime with High Efficiency

Abstract The limited operational stability of blue phosphorescent organic light‐emitting diodes (PhOLEDs) remains a major challenge for next‐generation display technologies. Herein, a highly stable deep blue PhOLED is reported, enabled by a newly designed Pt (II) complex, PtON‐2,6‐TPI, developed through a combination of density functional theory (DFT) calculations and automated quantitative structure‐activity relationship modeling (Auto‐QSAR). PtON‐2,6‐TPI exhibits enhanced exciton stability and broad recombination zone, attributed to its deep highest occupied molecular orbital (HOMO) level and sterically engineered ligand environment. Devices based on PtON‐2,6‐TPI demonstrate a twofold improvement in operational lifetime (LT ₉₀ 120 h at 1000 cd m ⁻² ) compared to the benchmarked PtON‐TBBI. A top‐emission OLED employing deuterated hosts and PtON‐2,6‐TPI achieves a narrow full‐width half maximum (FWHM) of 15 nm and extended operational stability with BT.2020 blue coordinates of (0.13, 0.05) (LT ₉₅ 193 h at 1000 cd m ⁻² ). Furthermore, a phosphorescent‐sensitized TADF (PST) device incorporating PtON‐2,6‐TPI as a sensitizer and a multiple‐resonance emitter as the terminal emitter delivers a record‐high external quantum efficiency (EQE) of 34.5% and a narrow FWHM of 16 nm in the deep‐blue region. This work highlights the critical role of DFT and machine learning‐assisted ligand design, offering a viable pathway toward commercially viable blue PhOLEDs.