Triangular BN-Embedded Molecular Carbons with Zigzag Edges and Their Dual Functionality in Fluoroanion Detection and...

Atomically precise synthesis of nanographenes containing polar boron-nitrogen (B-N) units, especially in a π-extended hexabenzocoronene (HBC) skeleton, has yet to be achieved, leaving this distinctive structural motif largely unexplored. Herein, we report the synthesis and characterization of two BN-embedded molecular carbons (BN-Ph and BN-OH), featuring regioselective construction of three BN bridges at the bay positions of the HBC. Incorporating B-N units into the aromatic framework produces unique solid-state stacking, photophysical properties, and electronic structures. Interestingly, despite the partial localization of BN bonds disrupting the continuous conjugation of azaborine rings, the global aromaticity of the molecular skeleton remains preserved. Furthermore, these BN-embedded nanographenes exhibited a sensitive response to fluoride anions, good reversibility, and coordination-induced color tunability. Notably, benefiting from pronounced local dipoles, extensive π-electron surfaces, and favorable energy level alignment, BN-Ph and BN-OH were further employed as interfacial layers in perovskite solar cells (PSCs). These BN-embedded carbon nanomaterials promote more efficient hole extraction and transport, leading to a significantly enhanced power conversion efficiency of 25.24% and an open-circuit voltage of 1.187 V, while their exceptional hydrophobicity substantially improved device stability, retaining over 90% of the initial efficiency after extended ambient exposure. These multifaceted findings, along with the versatile synthetic platform presented, open new avenues for designing chemically customized BN-based functional materials.