title: Two-step electrochemical synthesis of polypyrrole/reduced graphene oxide composites as efficient Pt-free counter electrode for plastic dye-sensitized solar cells.
abstract: Polypyrrole/reduced graphene oxide (PPy/RGO) composites on the rigid and plastic conducting substrates were fabricated via a facile two-step electrochemical process at low temperature. The polypyrrole/graphene oxide (PPy/GO) composites were first prepared on the substrate with electrochemical polymerization method, and the PPy/RGO composites were subsequently obtained by electrochemically reducing the PPy/GO. The resultant PPy/GO and PPy/RGO composites were porous, in contrast to the dense and flat pristine PPy films. The cyclic voltammetry measurement revealed that resultant composites exhibited a superior catalytic performance for triiodide reduction in the order of PPy/RGO > PPy/GO > PPy. The catalytic activity of PPy/RGO was comparable to that of Pt counter electrode (CE). Under the optimal conditions, an energy conversion efficiency of 6.45% was obtained for a rigid PPy/RGO-based dye-sensitized solar cell, which is 90% of that for a thermally deposited Pt-based device (7.14%). A plastic counter electrode was fabricated by depositing PPy/RGO composites on the plastic ITO/PEN substrate, and then an all-plastic device was assembled and exhibited an energy conversion efficiency of 4.25%, comparable to that of the counterpart using a sputtered-Pt CE (4.83%) on a plastic substrate. These results demonstrated that electrochemical synthesis is a facile low-temperature method to fabricate high-performance RGO/polymer composite-based CEs for plastic DSCs.
authors.affiliation: Department of Chemistry, School of Science, Beijing University of Chemical Technology , Beijing 100029, P. R. China.
authors.forename: Wantao
authors.initials: W
authors.lastname: Liu
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Fang
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lin
authors.forename: Xiong
authors.initials: X
authors.lastname: Yin
authors.forename: Guangshi
authors.initials: G
authors.lastname: Tang
authors.forename: Meng
authors.initials: M
authors.lastname: He
keywords: Pt-free; composites; dye-sensitized solar cells; electrochemical polymerization; low-temperature fabrication; plastic substrate; polypyrrole; reduced graphene oxide