NBN-doped nanographene embedded with five- and seven-membered rings on Au(111) surface

Abstract

anographenes (NGs) can be embedded with predesigned dopants or nonhexagonal rings to tailor the electronic properties and provide ideal platforms to study the unique physical and chemical properties. Here, we report the on-surface synthesis of NBN-doped NG embedded with five- and seven-membered rings (NBN-575-NG) on Au(111) from a oligophenylene precursor preinstalled with a NBN unit and a heptagonal ring. Scanning tunneling microscopy and non-contact atomic force microscopy images elucidate the intramolecular cyclodehydrogenation and the existence of the five- and seven-membered rings. Scanning tunneling spectroscopy spectra reveal that the NBN-575-NG is a semiconductor, which agrees with the density functional theory calculation results on a freestanding NBN-575-NG with the same structure. This work provides a feasible approach for the on-surface synthesis of novel NGs containing non-hexagonal rings.