Efficient Deep‐Blue TADF Emission from Multiheteroatom‐Doped Polycyclic Aromatic Hydrocarbon Embedded with Dual B─O Covalent Bonds

Abstract Boron‐doped polycyclic aromatic hydrocarbons (PAHs) have demonstrated exceptional potential in the development of high‐performance organic light‐emitting diodes (OLEDs). In this study, we propose a novel strategy for constructing PAH structures with thermally activated delayed fluorescence (TADF) properties by incorporating boron‐oxygen (B─O) covalent bonds, as opposed to doping isolated boron atoms. The newly designed multiheteroatom‐doped molecule, BNB‐OPTZ, was synthesized via a demethylation‐directed, lithium‐free methodology, achieving an impressive one‐pot yield exceeding 80%. BNB‐OPTZ adopts a symmetric, distorted semi‐planar rigid conformation. Theoretical calculations reveal its long‐range charge transfer characteristics. The molecule exhibits deep blue emission with a peak wavelength of 441 nm in toluene solution, accompanied by CIE coordinates of (0.14, 0.05). Notably, the blue OLED device using BNB‐OPTZ achieved a remarkable external quantum efficiency of 23.1%. These findings suggest that the incorporation of B─O covalent bonds into multiheteroatom‐doped PAH frameworks offers a promising design strategy for advancing PAH‐based blue‐light OLED applications.