Facile hydrothermal assisted synthesis of time dependent Cu2S thin films for efficient photoelectrochemical application

Abstract

In present investigation, we have successfully synthesized nanocrystalline Cu2S thin films at different deposition time via single step hydrothermal route. The synthesized Cu2S thin films characterized for their optostructural, morphological, compositional and photoelecrochemical properties as function of deposition time. Thickness of deposited Cu2S thin films increases with increase in deposition time. The optical studies revealed that band gap of Cu2S thin films decrease with increase in deposition time. Structural study confirm that Cu2S thin films are nanocrystalline in nature with pure hexagonal crystal structure. Crystallite size were increases with increase in deposition time. Raman spectrum shows the presence of sharp band at 472 cm−1 confirms the formation of pure phase hexagonal Cu2S thin film. Scanning electron microscopy micrographs of Cu2S thin films demonstrate that significant change in surface morphology. The high resolution transmission electron microscopy and selected area emission diffraction study indicate that nanocrystalline Cu2S thin films formation. X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy show the presence of elements and preferred valence state with stoichiometric composition of the Cu2S thin films. electron impedance spectroscopy reveals that charge transfer resistance (Rct) decreases with increase in deposition time. From J–V measurements, it was found that, Cu2S thin films shows maximum conversion efficiency is 0.27% for film after deposition of 6 h.