Highly Efficient Blue Electro‐Fluorescence and Hybrid White Electroluminescence Basing on a Novel Hybrid Local and Charge‐Transfer (HLCT) Material with Weak Donor–Acceptor Structure and High Carrier Mobilities

Abstract High efficiency and luminance are critical for commercialized blue organic light‐emitting diodes (OLEDs). Herein, a novel donor–acceptor (D–A) blue‐emissive molecule with a weak donor and acceptor is synthesized. The moderate hybrid local and charge transfer (HLCT) state character endows PPIBPO with blue fluorescence and high quantum efficiency. More importantly, the rigid, rod‐like molecular structure gives rise to the regularity of the stacking pattern of PPIBPO, which enables its extraordinary carrier mobilities in non‐doped OLED, the hole mobility and electron mobility are as high as 5.09 × 10 −5 cm 2 V −1 s −1 and 3.22 × 10 −4 cm 2 V −1 s −1 , respectively. The non‐doped blue OLED of PPIBPO achieves a maximum external quantum efficiency (EQE) of 12.0% and a maximum luminance of 55023 cd m −2 , which is one of the best values among the non‐doped blue OLEDs based on HLCT molecules. Furthermore, high‐efficiency two‐color hybrid warm white OLED with a maximum EQE up to 22.5% and maximum power efficiency of 87.0 lm W −1 is also achieved using PPIBPO as blue‐fluorophor.