Triptycene‐Fused Carbonyl‐Nitrogen Multiresonance Emitter for Efficient Green OLEDs With High Color Purity

Carbonyl‐nitrogen (CO‐N) multiresonance (MR) materials have emerged as promising candidates for ultra‐high‐definition displays due to their high color purity, but they often suffer from severe spectral broadening in organic light‐emitting diodes (OLEDs), which hinders the construction of wide‐color‐gamut displays. Herein, we report a novel molecule QA‐TP constructed by integrating bulky steric triptycene substituents into the CO‐N‐based trans‐quinacridone skeleton. The rigid 3D structure of QA‐TP can not only suppress molecular structural relaxation but also effectively restrict intermolecular stacking in the aggregated state, resulting in pure green emission with a narrow full width at half maximum (FWHM) value of 21 nm in toluene and 27 nm in doped film, both superior to the counterpart molecule QA‐4Ph. Furthermore, hyperfluorescent OLED based on QA‐TP emitter exhibits a satisfactory external quantum efficiency of 16.7% and a narrow FWHM of 27 nm, with CIE coordinates of (0.27, 0.66). These results verify the feasibility of directly incorporating rigid steric substituents into CO‐N MR skeletons for developing narrowband emitters as well as OLEDs.