A dye-sensitized solar cell based on natural photosensitizers and a PEDOT:PSS/TiO2 film as a counter electrode

¹ Photonics Research Group, Engineering Research Centre, Yazd University, 89158-17163 Yazd, Iran
² Atomic and Molecular Group, Faculty of Physics, Yazd University, 89158-17163 Yazd, Iran
³ Department of Chemistry, Faculty of Science, Yazd University, 89158-17163 Yazd, Iran

^a email: abehjat@yazd.ac.ir

Received: 16 September 2014
Revised: 14 December 2014
Accepted: 23 January 2015
Published online: 25 February 2015

Abstract

Poly(3, 4-ethylendioxythiophene)-poly(styrene sulfonate) mixed with TiO₂ nanoparticles (PEDOT:PSS/TiO₂) was used as a catalyst for tri-iodide reduction in dye-sensitized solar cells based on natural photosensitizers. A PEDOT:PSS/TiO₂ film was coated on a conductive glass substrate by the spin coating method. The solar cells were fabricated, having the PEDOT:PSS/TiO₂ film as a counter electrode and Pomegranate juice dye-sensitized TiO₂ as an anode. The morphology of PEDOT:PSS/TiO₂ films was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) images. Cyclic voltammetry (CV) was employed to characterize the catalytic activity of the PEDOT:PSS/TiO₂ film. Based on the analysis of CV, the enhancements for the electrochemical and photochemical performance of the PEDOT:PSS/TiO₂ electrode are attributed to the fact that the dispersed TiO₂ nanoparticles in the PEDOT:PSS matrix provide an improved catalytic activity and a facilitated diffusion for tri-iodide ions. The energy conversion efficiency is significantly improved after TiO₂ nanoparticle incorporation. This improvement might be attributed to an increase in the counter electrode catalytic activity. The highest efficiency of 0.73% was obtained by using 100 nm TiO₂ nanoparticles in the counter electrode.