title: Fully solution-processed transparent conducting oxide-free counter electrodes for dye-sensitized solar cells: spray-coated single-wall carbon nanotube thin films loaded with chemically-reduced platinum nanoparticles.
abstract: We report fully solution-processed fabrication of transparent conducting oxide-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) by combining spray-coating of single-wall carbon nanotubes (SWCNTs) and chemical reduction of chloroplatinic acid precursor to platinum nanoparticles (Pt NPs) with formic acid. The power conversion efficiency of a semitransparent DSSC with such SWCNT-based CE loaded with Pt NPs is comparable to that of a control device with a conventional CE. Quantification of Pt loading shows that network morphology of entangled SWCNTs is efficient in forming and retaining chemically reduced Pt NPs. Moreover, electron microscopy and electrochemical impedance spectroscopy results show that mainly Pt NPs, which are tens of nanometers in diameter and reside at the surface of SWCNT CEs, contribute to electrocatalytic activity for triiodide reduction, to which we attribute strong correlation between power conversion efficiency of DSSCs and time constant deduced from equivalent-circuit analysis of impedance spectra.
authors.affiliation: Department of Physics and Division of Energy Systems Research, Ajou University , Suwon 443-749, Korea.
authors.forename: Sang Yong
authors.initials: SY
authors.lastname: Kim
authors.forename: Yesel
authors.initials: Y
authors.lastname: Kim
authors.forename: Kyung Moon
authors.initials: KM
authors.lastname: Lee
authors.forename: Woo Sug
authors.initials: WS
authors.lastname: Yoon
authors.forename: Ho Seok
authors.initials: HS
authors.lastname: Lee
authors.forename: Jong Tae
authors.initials: JT
authors.lastname: Lee
authors.forename: Seung-Joo
authors.initials: SJ
authors.lastname: Kim
authors.forename: Yeong Hwan
authors.initials: YH
authors.lastname: Ahn
authors.forename: Ji-Yong
authors.initials: JY
authors.lastname: Park
authors.forename: Tai Kyu
authors.initials: TK
authors.lastname: Lee
authors.forename: Soonil
authors.initials: S
authors.lastname: Lee