Pt-free, low-cost and efficient counter electrode with carbon wrapped VO 2 (M) nanofiber for dye-sensitized solar cells

• Published in: Scientific reports Vol. 9; no. 1; p. 5177
• Main Authors: Gnanasekar, Subashini, Kollu, Pratap, Jeong, Soon Kwan, Grace, Andrews Nirmala
• Format: Journal Article
• Language: English
• Published: England 01.12.2019
• ISSN: 2045-2322
• DOI: 10.1038/s41598-019-41693-1

The present study reports the use of one-dimensional carbon wrapped VO (M) nanofiber (VO (M)/C) as a cost-effective counter electrode for dye-sensitized solar cells (DSSCs); where M denotes monoclinic crystal system. Uniform short length nanofiber was synthesised by a sol-gel based simple and versatile electrospinning and post carbonization technique. The investigation of nanostructure and morphological analysis were performed by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and transmission electron microscope (TEM) with EDAX. The electrochemical response was comprehensively characterized by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization. The electrochemical analysis of the VO (M)/C nanofiber counter electrode exhibits significant electrocatalytic activity towards the reduction of triiodide and low charge transfer resistance at the electrode-electrolyte interface. The DSSCs fabricated with carbon-wrapped VO (M) nanofiber CE showed high power conversion efficiency of 6.53% under standard test condition of simulated 1SUN illumination at AM1.5 G, which was comparable to the 7.39% observed for conventional thermally decomposed Pt CE based DSSC under same test conditions. This result encourages the next step of modification and use of low-cost VO (M) as an alternate counter electrode for DSSCs to achieve a substantial efficiency for future energy demand.