Bandgap tuning of polyvinyl alcohol capped alloyed Sn1-xCuxS nanostructures for optoelectronic applications

Abstract

In this work, the optical bandgap of polyvinyl alcohol (PVA) capped Sn1-xCuxS nanostructures have been tuned for optoelectronic applications. PVA capped Sn1-xCuxS (x: 0 to 0.30) nanostructures were prepared via chemical route. X-ray diffraction (XRD), FT-IR and UV–visible-NIR spectra measurements techniques were utilized to explore the structure, bonds’ vibrations and optical properties of the prepared nanostructures. XRD measurements reveal the crystalline nature of the prepared samples with the orthorhombic crystalline structure. Gaussian fitting software was used to de-convolute the XRD peaks of the capped Sn0.7Cu0.3S nanostructures. The crystallite size, micro strain and dislocation density of the capped Sn1-xCuxS nanostructures are investigated. FT-IR spectra analysis exhibits the successes of Cu alloying in the host SnS material. The UV–visible-NIR transmittance spectra of Sn1-xCuxS nanostructures are red-shifted to longer wavelength regions as × increases up to 0.15 and then it blue-shifted again to lower wavelength regions. The estimated optical bandgap of Sn1-xCuxS nanostructures is tuned from 1.83 eV to 1.25 eV as Cu molar ratio is increased up to 0.15, and it increases again to 1.36 eV as × is further increased to 0.30. These novel results are interpreted in terms of the created inter-band energy levels and quantum confinement effect. As environmentally-friendly nanostructures, PVA capped Sn1-xCuxS are highly appreciated in the scientific medium for optoelectronic applications.