Simple and inexpensive electrodeposited silver/polyaniline composite counter electrodes for dye-sensitized solar cells Sheeba Ghani • Rehana Sharif • Shamaila Shahzadi • N. Zafar • A. W. Anwar • Ayesha Ashraf • Azhar A. Zaidi • Afzal H. Kamboh • Saima Bashir Received: 20 September 2014 / Accepted: 5 November 2014 Ó Springer Science+Business Media New York 2014 Abstract Silver and polyaniline (Ag/PANI) composite counter electrodes (CEs) have been prepared by electro- chemical polymerization on stainless steel substrate using different silver (Ag) concentrations for dye-sensitized solar cells (DSSC). The effect of Ag concentration on the properties of fabricated Ag/PANI composite CEs, such as morphology, electrical conductivity, oxidation and reduc- tion potential, and electrochemical activity of I 3 - reduc- tion, is investigated. Highest cathodic current density (3.4 mA), low charge transfer resistance (2.15 X), and good electrocatalytic activity of I  3 =I  redox couple for CE are obtained at 0.07 M concentration of silver in Ag/PANI composite. DSSC based on this CE shows best photovol- taic performance with conversion efficiency up to 7.31 %. This study indicates that the Ag/PANI composite prepared electrochemically is possible substitute of the expensive Platinum as CEs for DSSCs. Introduction Dye-sensitized solar cells (DSSCs) are of great attention among solar cells due to low cost and high photovoltaic efficiency. The DSSC is composed of dye-sensitized TiO 2 photo electrode, a counter electrode (CE), and I  3 =I  redox electrolyte solution. The CE is key component in DSSC, which is used to shift electrons from outer circuit to the electrolyte solution and to reduce the triiodide ions (I  3 ) to Iodide ions (I) [1–4]. Generally, a thin platinum (Pt) film deposited on transparent conductive oxides (TCO) glass is widely adopted as CE in DSSC for the reduction of I  3 . However, Pt CE is expensive and restricts its use at com- mercial scale DSSC [5, 6]. To reduce the fabrication cost of DSSC, it is required to adopt cost-effective alternative materials such as carbonous materials, conducting poly- mers, and their composites for CEs [7–17]. Among conducting polymers, polyaniline (PANI) is the most attractive material to replace Pt CE because of its easy synthesis, considerable catalytic activity, and good environ- mental stability [18, 19]. Li et al. [20], Qin et al. [21], and Xiao et al. [22] use electrochemically polymerized Polyaniline film on ITO glass as a counter electrode for DSSC and achieve a conversion efficiency up to 5.8 % with smaller charge transfer resistance and higher electrolyte catalytic activity of I  3 =I  redox reaction. Typically, PANI has conductivity of the order of 1 S cm -1 . The coupling of metals with PANI is the most suitable choice to enhance its conductivity [23, 24]. The platinum nano-particle (PtNP)/PANI composite-based CEs have been investigated and exhibit unique properties of both PtNP and PANI. Higher conductivity is observed for the PtNP/PANI composite CE as compared to the PtNP and PANI CE. Consequently, PtNP/PANI composite-based DSSC showed better PV performance than the PANI and the Electronic supplementary material The online version of this article (doi:10.1007/s10853-014-8708-z) contains supplementary material, which is available to authorized users. S. Ghani (&)  R. Sharif  S. Shahzadi  N. Zafar  A. W. Anwar  A. Ashraf  A. A. Zaidi  S. Bashir Department of Physics, University of Engineering and Technology, Lahore, Pakistan e-mail: sheeba.ghani@yahoo.com A. H. Kamboh Pakistan Council of Renewable Energy Technologies, Islamabad, Pakistan 123 J Mater Sci DOI 10.1007/s10853-014-8708-z