title: Benzothienobenzothiophene-based conjugated oligomers as semiconductors for stable organic thin-film transistors.
abstract: Two benzothienobenzothiophene (BTBT)-based conjugated oligomers, i.e., 2,2'-bi[1]benzothieno[3,2-b][1]benzothiophene (1) and 5,5'-bis([1]benzothieno[3,2-b][1]benzothiophen-2-yl)-2,2'-bithiophene (2), were prepared and characterized. Both oligomers exhibit excellent thermal stability, with 5% weight-loss temperatures (T(L)) above 370 °C; no phase transition was observed before decomposition. The highest occupied molecular orbital (HOMO) levels of 1 and 2 are -5.3 and -4.9 eV, respectively, as measured by ultraviolet photoelectron spectroscopy. Thin-film X-ray diffraction and atomic force microscopy characterizations indicate that both oligomers form highly crystalline films with large domain sizes on octadecyltrimethoxysilane-modified substrates. Organic thin-film transistors with top-contact and bottom-gate geometry based on 1 and 2 exhibited mobilities up to 2.12 cm(2)/V·s for 1 and 1.39 cm(2)/V·s for 2 in an ambient atmosphere. 1-based devices exhibited great air and thermal stabilities, as evidenced by the slight performance degradation after 2 months of storage under ambient conditions and after thermal annealing at temperatures below 250 °C.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, People's Republic of China.
authors.forename: Han
authors.initials: H
authors.lastname: Yu
authors.forename: Weili
authors.initials: W
authors.lastname: Li
authors.forename: Hongkun
authors.initials: H
authors.lastname: Tian
authors.forename: Haibo
authors.initials: H
authors.lastname: Wang
authors.forename: Donghang
authors.initials: D
authors.lastname: Yan
authors.forename: Jingping
authors.initials: J
authors.lastname: Zhang
authors.forename: Yanhou
authors.initials: Y
authors.lastname: Geng
authors.forename: Fosong
authors.initials: F
authors.lastname: Wang