Undoped and In3+-doped WO3 electrodes coated with Cu7Te4 nanocrystals and Bi2Te3 thin films: Investigation of morphological, structural and optical properties

Abstract

In this study, we synthesized undoped and In3+-doped WO3 electrodes coated with hexagonal Cu7Te4 nanocrystals (NCs) and rhombohedral Bi2Te3 thin films. This was achieved using a solution process via successive ionic layer adsorption and reaction (SILAR), and the doctor blading method. Field emission scanning electron microscopy, X-ray diffraction, ultraviolet-visible spectroscopy, and room-temperature photoluminescence of the as-prepared electrodes, were performed. The structural parameters of the Cu7Te4 NCs and Bi2Te3 thin films on the In3+-doped WO3 film were also analyzed to confirm their morphological characteristics. We observed a change in the energy band gap (Eg) after coating with Cu7Te4(6)/Bi2Te3(4) film, explained by significant changes in morphology due to the coating process. Thus, we demonstrated that the synthesis and characteristics of these materials can be attributed to an increased capability in incident light harvesting across a broader optical spectral range, which may be used to further applications in optical and electronic devices.