Synthesis and characterization of terepthalaldehyde–thiocarbohydrazide polymer doped with Cu(II) and Zn(II) Metal ions for solar cell applications

A convenient synthesis method and the properties of a polynuclear Cu(II) and Zn(II) terapthaldehyde-thiocarbohydrazide polymeric metal complexes has been discussed in this work. A product of terepthalaldehyde–thiocarbohydrazide as condensed polymer (TThP) was synthesized by polycondensation reaction of terepthalaldehyde with thiocarbohydrazide. Two polymeric metal complexes of the condensed product [(C15H12N4S)2CuCl2]n (TThP–CuCl2) and [(C15H12N4S)2ZnCl2]n (TThP–ZnCl2) were prepared with CuCl2 and ZnCl2 metal salts separately and compared for property evaluation. Structural analysis was carried out by elemental analysis, SEM and FTIR, thermal analysis with the help of TGA and optical properties was carried with UV–visible and fluorescence techniques. TThP shows fluorescence at 424 nm at an excitation wavelength of 435 nm and its polymer complexes TThP–CuCl2 and TThP–ZnCl2 show fluorescence at the same wavelength with higher intensity. The band gap of the synthesized polymer metal complexes decrease from 3.3 to 2.6 eV as metals varied from M = Cu(II)–Zn(II). This confirms the successful inclusion of metals in polymer back bone.