MT-pyrene-Based Conductive Radical Cation Salts: Crystal and Electronic Structure and Transport Properties

With the characteristic two-dimensional (2D) electronic structure of 1,3,6,8-tetrakis(methylthio)pyrene (MT-pyrene), affording ultrahigh mobility on single-crystal field-effect transistors, we expected MT-pyrene to be a promising platform for highly conducting 2D metallic molecular conductors. To address this, we carried out electrochemical crystallization of MT-pyrene to obtain a series of conducting radical cation salts. Although some salts were highly conducting and showed metallic behavior at around room temperature, they became insulating at low temperatures. These conducting behaviors are consistent with their one-dimensional nature, which originates in the molecular arrangement in the solid state and the distribution of the HOMO in the MT-pyrene molecule.