Tunable Morphology of Polyaniline/Multi-wall Carbon Nanotube for Organic Solar Cells

Despite the great interest in applying polyaniline (PAni) in organic solar cells (OSCs), only a few studies deal with the morphology control of PAni-based OSCs. Here, comprehensive research has been conducted on the morphology control of PAni/multi-walled carbon nanotubes (MWCNTs) nanocomposites. Our results show that the morphology of PAni/MWCNTs can be tuned to tubular or cauliflower by controlling the synthesis parameters. The present study discusses the effect of the dopant's nature, the process's temperature, and the polymerization kinetics on the morphological dominance in the structure of PAni/MWCNTs nanocomposites. Also, the impact of the morphology of PAni/MWCNT on the efficiency of Photovoltaic cells based on these nanocomposites is investigated using Fourier transform-infrared spectroscopy, Hall effect measurements, UV-visible analyses for band gap measurements, and field emission scanning electron microscopy. The results revealed that by controlling morphology and achieving the desired morphology (tubular morphology), the conductivity of nanocomposite and mobility of the charge carriers increases. Consequently, it has been shown that the efficiency of PAni/MWCNTs OSCs increases due to the beneficial changes in short circuit current density, open voltage, and Fill Factor. Our results concluded that morphology control in synthesizing PAni/MWCNT nanocomposites plays a crucial role in the efficiency adjustment of the resultant photovoltaic devices.