High efficiency and low cost dye-sensitized solar cells (DSSCs) have attracted much attention very recently in the context of our need for an affordable renewable energy source. Inexpensive porous polyaniline nanotubes (PPNT-1) have been synthesized through a simple method via controlled polymerization of aniline with ammonium persulfate in the presence of concentrated orthophosphoric acid. PPNT-1 has been used as a substitute for platinum to construct the counter electrode (CE) in a DSSC, which showed lower charge transfer resistance and higher electrocatalytic activity for reduction of I-3(-) into I- than that of Pt electrode. PPNT-1-10T CE achieved a high conversion efficiency of 5.57%, matching the performance of otherwise identical DSSCs with Pt CE (5.20%). (C) 2014 Elsevier B.V. All rights reserved.