In this work, we successfully synthesized aluminum-doped polyaniline in various solvent media using chemical oxidation polymerization, and for the first time, investigated their applications as counter electrode (CE) in dye-sensitized solar cells (DSSCs). The experimental results (field emission scanning electron microscopy/energy dispersive X-ray analysis, atomic absorption spectrometer, Fourier transform infrared spectroscopy, thermogravimetric/differential thermal analysis, etc.) showed that critical properties such as crystallinity, conductivity, and surface area of PAni polymers can be controlled through both Al ions and/or solvent media. The photovoltaic performance of DSSCs was evaluated by current density–voltage (J–V) and external quantum efficiency measurements. The differences in the conversion efficiencies (η) were explained based on the electrocatalytic abilities and electron transfer properties of CEs. Of the CEs in various solvents, the P@6 CE in acetone showed the best electrocatalytic ability and highest η of 5.97%. This is even higher than that of the cell with Pt CE (5.75%). Furthermore, its stability under a prolonged irradiation is somewhat lower or close to the Pt CE, P@6 CE based DSSC showed the characteristics of rapid activity onset, high multiple start/stop capability, and superior irradiation stability. This novel concept—along with promising electrocatalytic activity and facile electron transfer—provides a new approach to enhance the photovoltaic performances of Pt-free DSSCs.

The present paper reports the fabrication and photovoltaic characterization of pure and dodecyl benzene sulfonic acid (DBSA)-doped polyaniline (PAni) micro-rods polymer/n-Si heterojunction solar cells, and also the morphological and structural properties of pure and micro-rods PAni doping with DBSA. The device shows a strong photovoltaic behavior with a maximum open-circuit voltage $V_{\mathit{o}\mathit{c}}$ of 0.83 V, a short-circuit current $J_{\mathit{s}\mathit{c}}$ of 14.72 mA cm⁻², fill factor $\mathit{F}\mathit{F}$ of 0.54 resulting in an estimated device efficiency $\eta$ of 6.13% under simulated solar light with the intensity of 100 mW/cm². The results indicate that the Au/DBSA-doped PAni micro-rods/n-Si heterojunction structure might be promising for the solar cell applications.