Molecular packing in CdS containing conducting polymer composite LB multilayers

Abstract

Langmuir–Blodgett (LB) technique has been used to deposit composite multilayers of poly (3-octylthiophene)-cadmium arachidate (POT-CdA) and polyaniline-cadmium arachidate (PANI-CdA). These were used as precursors to develop semiconducting CdS nanoclusters within the conducting polymer based multilayers. The presence of CdS in the multilayers was determined by Fourier transform infrared spectroscopy (FTIR), UV–Vis and Raman spectroscopy. The structural changes occurring as a consequence of CdS formation have been characterized using X-ray reflection and grazing incidence X-ray diffraction (GIXD) techniques. As-deposited POT-CdA multilayers exhibit good vertical as well as in-plane structure similar to that of CdA. In contrast, PANI-CdA multilayers have poor structural order. The in-plane molecular packing in CdA and PANI-CdA multilayers after H2S exposure has mixed domains of rectangular (herringbone) and hexagonal arrangements. In the case of POT-CdA multilayers, however, the original rectangular packing is retained.