title: Transient photoconductivity and femtosecond nonlinear optical properties of a conjugated polymer-graphene oxide composite.
abstract: A water soluble conjugated thiophene polymer, sodium salt of poly[2-(3-thienyl)ethoxy-4-butylsulfonate] (TPP), and graphene oxide (GO) composite film (GO-TPP) device was prepared. Transient photoconductivity measurements were carried out on the GO-TPP composite film using 150 ns laser pulses of 527 nm wavelength. Highly efficient photocurrent generation was observed from the GO-TPP film. The relationships of the film photoconductivity, photocurrent decay time and electron decay times with the incident light intensity were investigated. The photoconductive gain of the film was determined to be greater than 40% and to be independent of the light intensity. Furthermore, the femtosecond nonlinear optical properties of the GO-TPP film were measured using 800 nm femtosecond laser pulses and the composite film exhibited high nonlinear absorption and nonlinear refraction coefficients.
authors.affiliation: Department of Physics, National University of Singapore, Singapore, Singapore.
authors.forename: Venkatram
authors.initials: V
authors.lastname: Nalla
authors.forename: Lakshminarayana
authors.initials: L
authors.lastname: Polavarapu
authors.forename: Kiran Kumar
authors.initials: KK
authors.lastname: Manga
authors.forename: Bee Min
authors.initials: BM
authors.lastname: Goh
authors.forename: Kian Ping
authors.initials: KP
authors.lastname: Loh
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Ji