Efficient Deep‐Blue Fluorescent OLEDs Based on a D–π–A Emitter Profiting From Intramolecular Hydrogen Bonds and a Hybridized Excited State

Abstract

High performance deep‐blue emitters with a Commission International de l'Eclairage (CIE) coordinate of CIEy≤0.08 are highly desired in ultrahigh‐definition displays. Herein, we designed and synthesized an efficient D–π–A deep‐blue emitter, 2‐(6‐([1,1′ : 3′,1′′‐terphenyl]‐5′‐yl)pyridin‐3‐yl)‐1‐phenyl‐1H‐phenanthro[9,10‐d] imidazole (mPTPH), using the synergistic effect of intramolecular hydrogen bond (H‐bond) and hybridized excited state. Single‐crystal structure analysis confirmed that there exist intra‐ and intermolecular H‐bond interactions which could inhibit the structure vibration and increase photoluminescence efficiency. The photophysical and theoretical results show that mPTPH exhibited hybridized local and charge‐transfer (HLCT) feature with strong deep‐blue emission. Ultimately, the non‐doped device based on mPTPH exhibited high maximum luminance of 20610 cd m−2. The doped device achieved high maximum external quantum efficiency of 5.4 % and small efficiency roll‐off with deep‐blue emission peak of 413 nm and CIE coordinate of (0.16, 0.08).