Aiming for enhancing photovoltaic performances of DSSCs from polyaniline (PANi) counter electrodes (CEs), here we report the chemical deposition of dense PANi nanoparticle CEs. The dense nanopartides enhance the interfacial contact between PANi layer and fluorine doped tin oxide (FTC) conducting substrate. Comprehensive performances of H2SO4 doped PANi CE are better than that of HCl or H3PO4 doped PANi. Resultant PANi CEs are thoroughly characterized by scanning electron microscopy observation, X-ray diffraction patterns, electrochemical techniques, and spectral analysis such as UV-vis spectra, Fourier transform infrared spectra, Raman and NMR spectra. Owing to the long conjugation structure, high doping level and degree of electron delocalization, H2SO4 doped PANi CE displays good electrical conduction and electrocatalytical behaviors toward I-/I-3(-) redox species. A light-to-electric power conversion efficiency of 7.30% under 100 mW cm(-2) (AM1.5) has been determined from H2SO4 doped PANi-based DSSCs. (C) 2014 Elsevier Ltd. All rights reserved.