title: Effect of Chalcogens on Electronic and Photophysical Properties of Vinylene-Based Diketopyrrolopyrrole Copolymers.
abstract: Three vinylene linked diketopyrrolopyrrole based donor-acceptor (D-A) copolymers have been synthesized with phenyl, thienyl, and selenyl units as donors. Optical and electronic properties were investigated with UV-vis absorption spectroscopy, cyclic voltammetry, near edge X-ray absorption spectroscopy, organic field effect transistor (OFET) measurements, and density functional theory (DFT) calculations. Optical and electrochemical band gaps decrease in the order phenyl, thienyl, and selenyl. Only phenyl-based polymers are nonplanar, but the main contributor to the larger band gap is electronic, not structural effects. Thienyl and selenyl polymers exhibit ambipolar charge transport but with higher hole than electron mobility. Experimental and theoretical results predict the selenyl system to have the best transport properties, but OFET measurements prove the thienyl system to be superior with p-channel mobility as high as 0.1 cm(2) V(-1) s(-1).
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Joydeep
authors.initials: J
authors.lastname: Dhar
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Tushita
authors.initials: T
authors.lastname: Mukhopadhay
authors.affiliation: Department of Physics and Centre for Plastic Electronics, Blackett Laboratory, Imperial College London , London 7W72BW, U.K.
authors.forename: Nir
authors.initials: N
authors.lastname: Yaacobi-Gross
authors.affiliation: Department of Physics and Centre for Plastic Electronics, Blackett Laboratory, Imperial College London , London 7W72BW, U.K.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Anthopoulos
authors.affiliation: Department of Chemistry, Bilkent University , 06800 Bilkent, Ankara, Turkey.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Salzner
authors.affiliation: Synchrotron SOLEIL , L'Orme des Merisiers Saint-Aubin - BP 48, F-91192 Gif-sur-Yvette Cedex, France.
authors.forename: Sufal
authors.initials: S
authors.lastname: Swaraj
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Satish
authors.initials: S
authors.lastname: Patil