Effect of surfactant on optical and structural properties of chemically deposited MoBi2S5 thin films

Abstract

In the present report, we have synthesized MoBi₂S₅ thin films by the Arrested Precipitation Technique (APT). The deposited thin films were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDS), UV-visible spectroscopy etc. Characterization tools were employed for structure, morphology, chemical composition and optical properties. Further, the effect of tri-n-octyl phosphine oxide (TOPO) on the formation and properties of the MoBi₂S₅ thin films were investigated. XRD patterns confirmed that the crystallite size of the MoBi₂S₅ thin film is decreased by using TOPO surfactant. EDS analysis results are in good agreement with the proposed chemical composition. SEM images reveal that grain size decreases from 200 to 160 nm in the presence of TOPO surfactant. The UV-visible absorption spectra of MoBi₂S₅ thin films show strong absorption in the wavelength range 400–1100 nm. The optical band gap was calculated from absorption spectra and lies in the range 1.20–1.35 eV. Finally, these prepared electrodes were tested for their photoelectrochemical (PEC) performance in polyiodide electrolyte and results are promising.