Comparative studies of properties of CdSe/POMA hybrid films electrodeposited on HOPG, Au and Pt substrates

Abstract

A simple deposition method was used to prepare photoactive composites containing cadmium selenide (CdSe) and poly(o-methoxyaniline) (POMA) nanofilms deposited on various substrates: HOPG, Au and Pt. The films were fabricated in a configuration substrate/CdSe/POMA. The deposition conditions were electrode substrate dependent. It was determined that the lowest required energy for initiation of polymer deposition is in the order of HOPG<Au<Pt substrate. The photovoltage and photocurrent of fabricated composites depend on the substrate underneath. The highest photocurrents 1.4 mAcm–2 were observed for Pt/CdSe/POMA, while the highest photovoltage 406 mV and 455 mV was registered for Au/CdSe/POMA and Pt/CdSe composites. The AFM and XPS studies explained the influence of the deposition substrate on the formed hybrid's quality. The photodegradation mechanism of CdSe/POMA hybrid was proposed and the role of POMA layer was explained. It was detected that the recombination process depends on a structure of deposited layers. As determined by AFM, CdSe and POMA films are the most crystalline when deposited on Pt, what enhanced photocurrent comparing to other substrates. The thickness of the electrodeposited POMA films decreases in the order HOPG>Au>Pt substrates as concluded from the XPS spectra. The observed metal/CdSe/POMA electrodes restructuring may be explained as the formation of selenates, selenosulfites and hydrogen sulfide due the sacrifizing role of the polymer.