title: Fluorinated polyimide gate dielectrics for the advancing the electrical stability of organic field-effect transistors.
abstract: Organic field-effect transistors (OFETs) that operated with good electrical stability were prepared by synthesizing fluorinated polyimide (PI) gate dielectrics based on 6FDA-PDA-PDA PI and 6FDA-CF3Bz-PDA PI. 6FDA-PDA-PDA PI and 6FDA-CF3Bz-PDA PI contain 6 and 18 fluorine atoms per repeat unit, respectively. These fluorinated polymers provided smooth surface topographies and surface energies that decreased as the number of fluorine atoms in the polymer backbone increased. These properties led to a better crystalline morphology in the semiconductor film grown over their surfaces. The number of fluorine atoms in the PI backbone increased, the field-effect mobility improved, and the threshold voltage shifted toward positive values (from -0.38 to +2.21 V) in the OFETs with pentacene and triethylsilylethynyl anthradithiophene. In addition, the highly fluorinated polyimide dielectric showed negligible hysteresis and a notable gate bias stability under both a N2 environment and ambient air.
authors.affiliation: Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology , Pohang 790-784, South Korea.
authors.forename: Yonghwa
authors.initials: Y
authors.lastname: Baek
authors.forename: Sooman
authors.initials: S
authors.lastname: Lim
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Yoo
authors.forename: Lae Ho
authors.initials: LH
authors.lastname: Kim
authors.forename: Haekyoung
authors.initials: H
authors.lastname: Kim
authors.forename: Seung Woo
authors.initials: SW
authors.lastname: Lee
authors.forename: Se Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Chan Eon
authors.initials: CE
authors.lastname: Park
keywords: bias stress; charge trapping; fluorinated polyimide; gate dielectric; operation stability; organic field-effect transistor (OFET)