title: Solution-Processed Ambipolar Organic Thin-Film Transistors by Blending p- and n-Type Semiconductors: Solid Solution versus Microphase Separation.
abstract: Here, we report solid solution of p- and n-type organic semiconductors as a new type of p-n blend for solution-processed ambipolar organic thin film transistors (OTFTs). This study compares the solid-solution films of silylethynylated tetraazapentacene 1 (acceptor) and silylethynylated pentacene 2 (donor) with the microphase-separated films of 1 and 3, a heptagon-embedded analogue of 2. It is found that the solid solutions of (1)x(2)1-x function as ambipolar semiconductors, whose hole and electron mobilities are tunable by varying the ratio of 1 and 2 in the solid solution. The OTFTs of (1)0.5(2)0.5 exhibit relatively balanced hole and electron mobilities comparable to the highest values as reported for ambipolar OTFTs of stoichiometric donor-acceptor cocrystals and microphase-separated p-n bulk heterojunctions. The solid solution of (1)0.5(2)0.5 and the microphase-separated blend of 1:3 (0.5:0.5) in OTFTs exhibit different responses to light in terms of absorption and photoeffect of OTFTs because the donor and acceptor are mixed at molecular level with π-π stacking in the solid solution.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Xu
authors.forename: Ting
authors.initials: T
authors.lastname: Xiao
authors.forename: Xiao
authors.initials: X
authors.lastname: Gu
authors.forename: Xuejin
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Physics and Materials Science and Centre for Functional Photonics (CFP), City University of Hong Kong , Kowloon, Hong Kong, China.
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Kershaw
authors.forename: Ni
authors.initials: N
authors.lastname: Zhao
authors.forename: Jianbin
authors.initials: J
authors.lastname: Xu
authors.forename: Qian
authors.initials: Q
authors.lastname: Miao
keywords: ambipolar; microphase separation; organic semiconductors; organic thin film transistors; solid solution