title: Tri-iodide reduction activity of ultra-small size PtFe nanoparticles supported nitrogen-doped graphene as counter electrode for dye-sensitized solar cell.
abstract: Efficient and cost effective counter electrode (CE) is pre-requisite for the commercialization of dye-sensitized solar cell (DSSC). Present work investigates ultra small size platinum-iron alloy nanoparticles dispersed over nitrogen-doped graphene (PtFe/NG) as an effective counter electrode for DSSC. Hereby we achieve low loading of Pt by alloying with Fe accompanied by superior electrocatalytic activity towards the iodide-triiodide (I-/I3-) mechanism. Enhancement in electrocatalytic performance of PtFe/NG has been shown by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization analysis. PtFe/NG counter electrode exhibits higher power conversion efficiency (∼6.12%) with lower charge transfer resistance, which helps in faster diffusion of I-/I3-ions as compared to NG and Pt/NG counter electrodes. The increased electrocatalytic activity of PtFe/NG is due to the collective effect of intrinsic electronic effects by alloying, uniform dispersion of small PtFe alloy nanoparticles over nitrogen doped graphene, and additional catalytic sites offered by nitrogen-doped graphene.
authors.affiliation: Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials Technology Centre (NFMTC), Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India.
authors.forename: Divya
authors.initials: D
authors.lastname: Nechiyil
authors.affiliation: Helmholtz Institute Ulm for Electrochemical Storage (HIU), Helmholtzstr. 11, D-89081 Ulm, Germany.
authors.forename: B P
authors.initials: BP
authors.lastname: Vinayan
authors.affiliation: Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials Technology Centre (NFMTC), Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India. Electronic address: ramp@iitm.ac.in.
authors.forename: S
authors.initials: S
authors.lastname: Ramaprabhu
keywords: Counter electrode; DSSC; Electrocatalytic activity; Graphene; Power conversion efficiency