Host Engineering of Deep‐Blue‐Fluorescent Organic Light‐Emitting Diodes with High Operational Stability and Narrowband Emission

The realization of highly operationally stable blue organic light‐emitting diodes (OLEDs) is a challenge in both academia and industry. This paper describes the development of anthracene–dibenzofuran host materials, 2‐(10‐(naphthalen‐1‐yl)anthracen‐9‐yl)naphtho[2,3‐b]benzofuran (Host 1) and 2‐(10‐([1,1′‐biphenyl]‐2‐yl)anthracen‐9‐yl)naphtho[2,3‐b]benzofuran (Host 2), namely for use in the emissive layer of an OLED stack. A multiple‐resonance thermally activated delayed serves as the blue fluorescence emitter and exhibits an initial luminance of 1000 cd m−2 and long operational stability (i.e., time to decay to 90% of initial luminance) of 249 h. Furthermore, a deep‐blue OLED with an optimized top‐emitting architecture with a high current efficiency of 154.3 cd A−1, is fabricated and calibrated to a Commission International de l’Éclairage y chromaticity coordinate of 0.048. Moreover, the emission spectrum of this OLED has a narrowband peak at 476 nm with a full width at half maximum (FWHM) of 16 nm. This work provides valuable insights into the design of anthracene‐based host materials and highlights the importance of host optimization in improving the operational stability of OLEDs.