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

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.