title: Thin Film Transistor Gas Sensors Incorporating High-Mobility Diketopyrrolopyrole-Based Polymeric Semiconductor Doped with Graphene Oxide.
abstract: In this work, we fabricated a diketopyrrolopyrole-based donor-acceptor copolymer composite film. This is a high-mobility semiconductor component with a functionalized-graphene-oxide (GO) gas-adsorbing dopant, used as an active layer in gas-sensing organic-field-effect transistor (OFET) devices. The GO content of the composite film was carefully controlled so that the crystalline orientation of the semiconducting polymer could be conserved, without compromising its gas-adsorbing ability. The resulting optimized device exhibited high mobility (>1 cm(2) V(-1) s(-1)) and revealed sensitive response during programmed exposure to various polar organic molecules (i.e., ethanol, acetone, and acetonitrile). This can be attributed to the high mobility of polymeric semiconductors, and also to their high surface-to-volume ratio of GO. The operating mechanism of the gas sensing GO-OFET is fully discussed in conjunction with charge-carrier trap theory. It was found that each transistor parameter (e.g., mobility, threshold voltage), responds independently to each gas molecule, which enables high selectivity of GO-OFETs for various gases. Furthermore, we also demonstrated practical GO-OFET devices that operated at low voltage (<1.5 V), and which successfully responded to gas exposure.
authors.affiliation: †School of Chemical Engineering and Material Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Kwang Hee
authors.initials: KH
authors.lastname: Cheon
authors.affiliation: †School of Chemical Engineering and Material Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Jangwhan
authors.initials: J
authors.lastname: Cho
authors.affiliation: ‡Department of Chemistry and ERI, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Yun-Hi
authors.initials: YH
authors.lastname: Kim
authors.affiliation: †School of Chemical Engineering and Material Science, Chung-Ang University, Seoul 156-756, Korea.
authors.forename: Dae Sung
authors.initials: DS
authors.lastname: Chung
keywords: gas detector; gas sensor; graphene oxide; high sensitivity; organic field effect transistor