Synthesis, structure, and optical properties of the nanocrystalline bismuth oxyiodide (BiOI) for optoelectronic application

• Published in: Optical materials 2020-11, Vol.109, p.110413, Article 110413
• Main Authors: Abuelwafa, A.A., Matiur, R.MD, Putri, Anissa A., Soga, T.
• Format: Article
• Language: English
• Subjects: Bismuth oxyiodide; Non-linear optical; Optical properties; SILAR; Thin films technology
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2020.110413

The present work demonstrates the synthesis of bismuth oxyiodide onto FTO substrates (BiOI/FTO) via successive ionic layer adsorption and reaction technique (SILAR). X-ray diffraction (XRD), Raman spectroscopy, and field emission scanning electron microscopy (FESEM) were used to study influences of deposition cycles on the structural and surface morphology of the BiOI/FTO films, respectively. Moreover, the chemical composition of samples was investigated using the energy dispersive X-ray spectroscopy (EDX)/elements mapping. The results were clarified the purity and nanostructures features of the BiOI thin films. The optical parameters of BiOI/FTO films were measured using the optical transmission spectra T (λ) and reflectance R (λ) in the wavelength range of 300–1500 nm. The estimated indirect optical band gap was decreased from 2.06 to 1.79 eV as deposition cycles were increased. The refractive-index at abnormal dispersion region was analyzed and considered in terms of single-oscillator models. Influences of deposition cycles on the optical dielectric constant, loss energy functions, and optical conductivity were estimated and discussed. In addition, nonlinear parameters such as third-order nonlinear susceptibility χ(3), non-linear refractive index n(2), and nonlinear absorption coefficient (βc) were estimated based on semi-empirical relation. So, the distinctive optical parameters for BiOI/FTO were concluded to be promising as an optical system for nonlinear optical devices. [Display omitted] •SILAR prepared BiOI/FTO thin films for optoelectronic devices.•Deposition cycles have an impact on the surface morphology of the BiOI/FTO films.•The deposition cycle causes the reduction of the optical energy gap (2.06–1.79 eV).•The deposition cycle provides a way to tune the value of the optical parameters of BiOI/FTO films.