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.

As known, in the synthesis of conductive polyaniline polymer from aniline monomer, the polymerization medium must be acidic. In order to make the polymerization medium acidic, protonic acids such as HCl and H2SO4 are generally used. In this study, two acids have been used to make the polymerization medium acidic. One of them, as we know, is H2SO4 as a protonic acid. The other acid is the zinc ion, which is a Lewis acid. The metal ion has never been used for this purpose up to now. Two polyaniline polymers have been synthesized to prove that conductive polymers can also be synthesized in the presence of metal ions instead of protonic acid. One of them is the polyaniline polymer, synthesized in the presence of H2SO4(PANI). The other polymer is polyaniline polymer, synthesized in the presence of zinc ions as acid (PANI-Zn-PSS). The synthesized polymers have been characterized by using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), X-ray diffraction diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible spectrophotometer (UV-vis.), thermal analysis techniques (thermo-gravimetric analysis, TGA)/differential thermal analysis, DTA) and electrical conductivity measurements kit. The photocatalytic activities of polymers synthesized have been investigated by the degradation of methylene blue (MB) dye in aqueous medium under UV light.

1. Conductive polymers are commonly referred to as “synthetic metals” due to the similarity of their electronic properties to those of metals. Among these materials, polyaniline, polypyrrole, and p...

In this study, three polyaniline (PANI) samples were synthesized under different experimental conditions to investigate the effects of potassium 3-(trifluoromethyl)phenyltrifluoroborate (PTMPB) and Ni(II) ions on their physicochemical and photocatalytic properties. To the best of our knowledge, PTMPB and Ni(II) were used for the first time in PANI synthesis as a dopant and a Lewis acid, respectively. Three different PANI samples were synthesized: PANI A in the presence of aniline, HCl, and the oxidant H₅IO₆; PANI B in the presence of aniline, HCl, PTMPB, and the oxidant; and PANI C in the presence of aniline, PTMPB, Ni(II) ions, and the oxidant. The synthesized polymers were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and electrical conductivity measurements. The characterization results revealed that the synthesis conditions significantly affected the morphology, crystallinity, thermal behavior, and electrical conductivity of the polymers. The photocatalytic activities of the polymers were evaluated through the degradation of methylene blue (MB) under UV irradiation. After 300 min, the degradation efficiencies of PANI A, PANI B, and PANI C were found to be 72.02%, 87.55%, and 94.91%, respectively. Kinetic analysis showed that the degradation process was consistent with the pseudo-first-order kinetic model, with apparent rate constants of 0.00194, 0.00265, and 0.00576 min⁻¹ for PANI A, PANI B, and PANI C, respectively. The results indicate that the incorporation of PTMPB and Ni(II) ions is an effective strategy for enhancing the performance of PANI in the degradation of MB under UV irradiation.