Deep‐Blue Through‐Space Charge‐Transfer MR‐TADF Emitters With Anthracene Linkers for Narrowband Fluorescent OLEDs

ABSTRACT Multiple‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters are attractive candidates for high‐definition OLED displays owing to their narrowband emission and high efficiency. However, most reported through‐space charge‐transfer (TSCT) MR‐TADF compounds emit in the green region and suffer from limited operational stability, leaving deep‐blue, narrowband MR‐TADF emitters underexplored. Herein, we report a series of TSCT MR‐TADF emitters based on an anthracene linker and U‐shaped molecular confinement. By incorporating an extended anthracene bridge, carbazolyl substitution, and targeted deuteration, this molecular design modulates TSCT character, suppresses high‐frequency vibrational modes, and enhances molecular rigidity. These compounds exhibit saturated blue to green emission with photoluminescence quantum yields (PLQYs) over 90%, full widths at half maximum (FWHMs) of approximately 30 nm in thin films, and reverse intersystem crossing rate constants (k RISC ) values up to 1.2 × 10 5 s −1 . D‐U‐OBN‐tCz enabled a deep‐blue non‐sensitized TADF OLED with an EQE of up to 20% and CIE coordinates of (0.15, 0.07). These findings demonstrate an effective molecular design platform for realizing color‐pure and operationally stable deep‐blue MR‐TADF emitters for OLED displays.