Research Article Impedance Spectroscopic Investigation of the Degraded Dye-Sensitized Solar Cell due to Ageing Parth Bhatt, 1 Kavita Pandey, 1,2 Pankaj Yadav, 3 Brijesh Tripathi, 4 and Manoj Kumar 4 1 Department of Solar Energy, School of Technology, Pandit Deendayal Petroleum University, Gandhinagar 382007, India 2 Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OXI 3QR, UK 3 Department of Electrical Engineering, Incheon National University, Incheon 406772, Republic of Korea 4 Department of Science, School of Technology, Pandit Deendayal Petroleum University, Gandhinagar 382007, India Correspondence should be addressed to Manoj Kumar; manoj.kspv@gmail.com Received 19 July 2016; Accepted 9 November 2016 Academic Editor: Francisco R. Zepeda Copyright © 2016 Parth Bhatt et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tis paper investigates the efect of ageing on the performance of dye-sensitized solar cells (DSCs). Te electrical characterization of fresh and degraded DSCs is done under AM1.5G spectrum and the current density-voltage (J-V) characteristics are analyzed. Short circuit current density ( SC ) decreases signifcantly whereas a noticeable increase in open circuit voltage is observed. Tese results have been further investigated electroanalytically using electrochemical impedance spectroscopy (EIS). An increase in net resistance results in a lower  SC for the degraded DSC. Tis decrease in current is mainly due to degradation of TiO 2 -dye interface, which is observed from light and dark J-V characteristics and is further confrmed by EIS measurements. A reduction in the chemical capacitance of the degraded DSC is observed, which is responsible for the shifing of Fermi level with respect to conduction band edge that further results in an increase of open circuit voltage for the degraded DSC. It is also confrmed from EIS that the degradation leads to a better contact formation between the electrolyte and Pt electrode, which improves the fll factor of the DSC. But the recombination throughout the DSC is found to increase along with degradation. Tis study suggests that the DSC should be used under low illumination conditions and around room temperature for a longer life. 1. Introduction Te metal oxide based dye-sensitized solar cells (DSCs) have attracted signifcant attention of researchers in recent years, because of their economic fabrication process and efcient working under difuse illumination. Te highest certifed device efciency has reached 11.9% [1]. A DSC module of large area (100 cm 2 ) has been demonstrated with an efciency of 8.4% [2]. Te DSC was explicated by O’Regan and Gr¨ atzel [3], which operates by exposing dye molecules to light that releases excited electrons to oxidize the dye, which is then restored by electron donation from the redox couples (iodide/triiodide, I − /I 3 − ) in the electrolyte. Te redox couples are then revived by counter electrode with electrons extracted from the working electrode via the external load circuitry. Tough the DSCs have demonstrated a highly promising performance instantly, the long term performance plays a major role in the commercialization of a solar PV technology. Te poor stability of DSC is mainly directed by the degradation mechanism occurring at diferent layers of the device afer prolonged operation. So, the analysis of the degradation mechanisms within DSC is of great interest to explore the factors afecting the performance of DSCs. Only a few papers present the stability studies of DSC [4–9]. Diferent techniques have been used to analyze the degradation mechanisms in DSCs; Uam et al. [10] used UV- vis absorption spectroscopy to identify that the desorption of dye on the TiO 2 surface was the reason for current density reduction in an aged cell. Additionally, Tatay et al. [11] accompanied the UV-vis absorption spectroscopy with luminescence and cyclic voltammetry and observed that organic dyes formed molecular aggregates which could deteriorate the device efciency. Also, there are few studies which used electrochemical impedance spectroscopy (EIS) Hindawi Publishing Corporation International Journal of Photoenergy Volume 2016, Article ID 8523150, 9 pages http://dx.doi.org/10.1155/2016/8523150