Effects of solvent and copper-doping on polyaniline conducting polymer and its application as a counter electrode for efficient and cost-effective dye-sensitized solar cells

Abstract

In this study, the synthesis of Copper-doped polyaniline (NPANI-Cu-X) was performed in the following solvents: H2O, DMF, DO, THF, ACTN and ACN, and then the solvent effects on the formation of NPANI-Cu-X (X represents the dopants, I- and BF4-) were investigated. NPANI-Cu-X was characterized using scanning electron microscopy (SEM), X-ray diffractions (XRD), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared spectrometry (FTIR), Atomic Absorption spectrometer (AAS), Ultraviolet-visible spectrophotometers (UV-vis), thermal analysis (TGA, DTA) and electrical conductivity measurements. The results show that the solvent is effective in the formation of NPANI-Cu-X. This effect was observed in the polymer structures, conductivities, copper contents and crystalline structures. The NPANI-Cu-X polymers synthesized with the various solvents were notably different from each other because some of the solvents create a copper-solvent complex with the copper. To understand the influence of solvent type and Cu inclusion on photoelectric performance, the obtained PANI were employed as counter electrode in a DSSC configuration. The highest double layer capacitance (24.1 mu F), low charge transfer resistance (5.13 Omega) together with series resistance (14.62 Omega), and good photovoltaic performance with conversion efficiency (6.37%) for counter electrodes are obtained the NPANI-Cu-X in ACN solvent media which is higher than that fabricated with N-PANI in same solvent media (1.36%). These results represent a promising route for developing new counter electrodes of Pt-free DSSCs by Cu doping and choosing an appropriate solvent. (C) 2015 Elsevier B.V. All rights reserved.