Efficient Blue Electroluminescence Based on A Donor‐π‐acceptor with Pyrene Bridge: Weak Charge‐transfer (CT) For High Luminescence and Considerable Exciton Utilization

Blue emitters are crucial in the organic light emitting diode (OLED) industry and scientific field. In this work, we prepared a novel donor‐π‐acceptor (D‐π‐A) molecular PCZ‐P‐PY using pyrene as a bridge to construct hybrid local and charge‐transfer (HLCT) state with weak charge‐transfer (CT) property. This excited state design give rise to the high photoluminescent quantum yield (PLQY), more importantly, it is also responsible for the high exciton utilization efficiency (EUE) by constructing efficient hot‐exciton channel. As a result, exceeding external quantum efficiency (EQE) of 5.7% is achieved in the non‐doped OLED of PCZ‐P‐PY with exceeding EUE of up to 90%.