Opto-electronic studies and diode applications: synthesis, characterization, and photoconductive properties of Schiff base and its Pd(II) and Pt(II) complexes

Abstract

This research involved the creation of a Schiff base ligand, (E)-6-tert-butyl 3-ethyl 2-(3-methoxy-4-phenoxybenzylideneamino)-4,5-dihydrothieno[2,3-c]pyridine-3,6(7H)-dicarboxylate (SB), through the condensation reaction of 6-tert-butyl 3-ethyl 2-amino-4,5-dihydrothieno[2,3-c]pyridine-3,6(7H)-dicarboxylate with 3-methoxy-4-phenoxybenzaldehyde. The synthesized Schiff base was then used to form metal complexes with Pd(II) and Pt(II) metal ions. Various analytical techniques, including microanalysis (C, H, N, and S), FT-IR, 1H-NMR, 13C-NMR, UV–Vis., thermal analysis (TGA), powder XRD analysis, mass (ESI), molar conductivity, and magnetic susceptibility, were employed to confirm the structures of synthesized compounds. Spectroscopic data indicated that the Schiff base functions as a chelating agent, utilizing oxygen and nitrogen donor sites. The molar conductance measurements suggested that both complexes are non-electrolytic. A square planar structure was proposed for the Pd(II) and Pt(II) complexes. The study also investigated the electronic and photonic characteristics of the metal complexes under different conditions. Furthermore, a basic diode was fabricated using the metal complex, and its electronic and photonic characteristics were thoroughly investigated. Current–voltage (I-V) measurements showed that the diode based on the Pd(II) complex had notable noise and a high leakage current. On the other hand, the diode with the Pt(II) complex exhibited enhanced photoconductivity as the light intensity increased.