Modification at the C1 Site of Spiro‐Structure to Achieve Violet‐Blue Emission

Abstract Violet‐blue organic emitters have considerable potential for application and can open up diverse development directions for future organic light‐emitting diode (OLED) technology, but relevant development is still relatively scarce. Here, we report a violet‐blue emitter based on through‐space charge transfer characteristics, namely 10‐phenyl‐1′‐(4‐(1‐phenyl‐1 H ‐phenanthro[9,10‐d]imidazol‐2‐yl)phenyl)‐10 H ‐spiro[acridine‐9,9′‐fluorene] ( SAF‐PPI ). This emitter uses fluorene units as the rigid linker to position donor and acceptor subunits in the vicinity, thereby effectively controlling the molecular spacing configuration and achieving hybridized local and charge transfer properties. In addition, OLEDs fabricated using SAF‐PPI as an emitter achieve a maximum external quantum efficiency value of 3.3%, with an emission peak at 418 nm and Commission Internationale de l'Eclairage coordinates of (0.15, 0.04). This molecular design strategy holds promise for advancing the development of short‐wavelength violet OLEDs.