title: N,N'-Bis(2-cyclohexylethyl)naphtho[2,3-b:6,7-b']dithiophene Diimides: Effects of Substituents.
abstract: Naphtho[2,3-b:6,7-b']dithiophene-4,5,9,10-tetracarboxylic diimide (NDTI) is a promising electron-deficient building block for n-type organic conductors, and the performance of NDTI-based field-effect transistors (FETs) is largely dependent on the substituents that alter the supramolecular organization in the solid state and, in turn, the intermolecular orbital overlap. For this reason, the rational selection of substituent on imide nitrogen atoms and/or thiophene α-positions is the key to developing superior n-type organic semiconductors. We here report new NDTI derivatives having N-(2-cyclohexylethyl) groups. Despite their one-dimensional packing structures in the solid state regardless of the presence or absence of chlorine groups at the thiophene α-positions, their FETs show promising performance with electron mobilities higher than 0.1 cm²·V(-1)·s(-1) under ambient conditions. We also discuss how the cyclohexylethyl groups affect the packing structure in comparison with analogous n-octyl derivatives having the same number of carbon atoms.
authors.affiliation: Emergent Molecular Function Research Group, RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. masahiro.nakano@riken.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Materials Characterization Support Unit, RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. hashi@riken.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hashizume
authors.affiliation: Emergent Molecular Function Research Group, RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. takimiya@riken.jp.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Takimiya
mesh_terms: D055772:Green Chemistry Technology; D007094:Imides / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D012666:Semiconductors
chemical_list: D007094:Imides
keywords: application of naphthalene diimide; crystal structure; organic field-effect transistor; organic synthesis; supramolecular chemistry