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 (24.1μF), low charge transfer resistance (5.13Ω) together with series resistance (14.62Ω), 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.