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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
journal contribution
posted on 2014-08-27, 00:00 authored by Sang Yong Kim, Yesel Kim, Kyung
Moon Lee, Woo Sug Yoon, Ho Seok Lee, Jong Tae Lee, Seung-Joo Kim, Yeong Hwan Ahn, Ji-Yong Park, Tai Kyu Lee, Soonil LeeWe
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.