Characterization and Thermal Study of Schiff-Base Monomers and Its Transition Metal Polychelates and Their Photovoltaic Performance on Dye Sensitized Solar Cells

Abstract

Azo dye monomer 4,4′-(4,4′-biphenylylenebisazo)-disalicylaldehyde-4n-butylphenyl aniline (H₂A) is synthesised by the reaction of 4,4′-bis[(salicylaldehyde-5)-azo]biphenyl (Azo) and n-butylaniline in the 1:2 molar ratio and its metal polychelates are also synthesized with Co(II), Ni(II), Cu(II), and Zn(II) metal ions. The synthesized compounds are characterized by ¹H, ¹³C NMR, Fourier transform infrared (FT-IR) spectroscopy, electronic spectra (UV-Vis), elemental analysis (C, H, N, O), gas chromatography-mass (GCmass) spectrometry, magnetic susceptibility and molar conductivity techniques. Thermal properties of the title compounds are studied using the thermogravimetric analysis (TGA). The metal molar ratio in all of the polychelates is found to be consistent with 1:1 (metal/ligand) stoichiometry. The influence of organic dyes H₂A and the [CuA(H₂O)₂]_n polychelate are investigated as photosensitizers on the photovoltaic parameters by current–voltage (I–V) measurements on TiO₂ photoelectrode dye sensitized solar cells (DSSCs). The [CuA(H₂O)₂]_n metal polychelate demonstrates the best performance as compared to the cell sensitized with H₂A.