Chemical Bonding and Electronic Structure in CdS/GO and CdSSe/GO Multilayer Films

The local atomic structure of multilayer films of graphene oxide, cadmium sulfide, and cadmium sulfide–selenide was analyzed by X-ray absorption fine structure spectroscopy. The films were prepared by sequential electrophoretic deposition and successive ion layer adsorption and reaction onto F-doped SnO2 substrates. The obtained films were characterized by scanning electron microscopy, energy dispersive spectroscopy, Raman spectroscopy, UV–vis spectroscopy, and step-potential photocurrent response. From the transmittance data analysis, a direct band gap ranging from 2.13 to 2.3 eV was deduced. From photocurrent measurements, we conclude that films of CdS and CdSSe have photovoltaic properties suitable for utilization as an active layer in multilayer thin film hybrid solar cells. X-ray absorption near-edge structure spectra show a difference in amplitude between CdS/GO and CdSSe/GO samples, ascribed to a change in the local electronic structure around S. Extended X-ray absorption fine structure spectra sho...