Synthesis of poly (3-hexylthiophene-2,5-diyl) in presence of CdS nanoparticles: microscopic and spectroscopic studies

Abstract

In this paper, the synthesis of nanocomposites of poly(3-hexylthiophene-2,5-diyl)) (P3HT) and cadmium sulfide (CdS) nanoparticles are reported. CdS nanoparticles were first synthesized using chemical precipitation. Then P3HT was synthesized by direct oxidation of 3-hexylthiophene with FeCl$_3$ as oxidant in presence of CdS nanoparticles. The goal of this work was to investigate the effect of the CdS nanoparticles during the synthesis of P3HT. The resulting films of P3HT/CdS nanocomposites were investigated by Fourier Transform Infrared Spectroscopy (FT-IR), Ultraviolet-Visible Spectroscopy (UV-Vis), X-Ray diffraction, Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Homogeneous distribution of CdS nanoparticles in P3HT was demonstrated by SEM, AFM and TEM. FTIR analysis showed interaction between CdS and the S atoms of the thiophene rings. This result, together with UV-Vis spectra and XRD patterns suggest a better arrangement of the polymer chains. It is possible that the CdS nanoparticles are coupled with the unpaired electrons of S atoms in the thiophene rings through the positive delocalized charge, resulting in a more ordered P3HT polymer matrix with embedded CdS nanoparticles.