title: Conductive nanoscopic fibrous assemblies containing helical tetrathiafulvalene stacks.
abstract: Tetrathiafulvalenes (TTF) S-TTF and R-TTF having four chiral amide end groups self-organize into helical nanofibers in the presence of 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyano-p-quinodimethane (F(4)TCNQ). The intermolecular hydrogen bonding among chiral amide end groups and the formation of charge-transfer complexes results in a long one-dimensional supramolecular stacking, and the chirality of the end groups affects the molecular orientation of TTF cores within the stacks. Electronic conductivity of a single helical nanoscopic fiber made of S-TTF and F(4)TCNQ is determined to be (7.0+/-3.0)x10(-4) S cm(-1) by point-contact current-imaging (PCI) AFM measurement. Nonwoven fabric composed of helical nanofibers shows a semiconducting temperature dependence with an activation energy of 0.18 eV.
authors: Collaborative Innovation Center for Nanotech FIBER, Shinshu University, Ueda 386-8567, Japan. ytatewa@shinshu-u.ac.jp
authors: Yoko
authors: Y
authors: Tatewaki
authors: Tatsuya
authors: T
authors: Hatanaka
authors: Ryo
authors: R
authors: Tsunashima
authors: Takayoshi
authors: T
authors: Nakamura
authors: Mutsumi
authors: M
authors: Kimura
authors: Hirofusa
authors: H
authors: Shirai