Effects of precursor salts on the morphological, optical, and structural properties of NiO synthesized using a hydrothermal route

Abstract

A typical transparent conductive oxide with inherent p-type conductivity is nickel oxide (NiO). Recently, due to its intriguing properties such as chemical stability, morphology, optical properties, and electrical properties, NiO has been recognized as one of the most auspicious oxides developed via various techniques and employed in optoelectronic applications. For this study, nickel chloride and nickel nitrate were used as precursors to create NiO nanostructures through a simple hydrothermal technique. XRD, FTIR, FESEM, and UV–Visible spectroscopy were used to analyze the nanostructures. XRD showed the phase identification and the lack of impurities in the cubic NiO nanostructures. FESEM showed the formation of irregular shaped nanoparticles of different sizes. FTIR suggested the presence of M – O bonds. Tauc's plots were used to calculate the direct optical band gaps of the samples, which were between 3.05 and 3.27 eV. The mechanism of formation and the reasons for the observed effect were discussed. This technique can be used to control the optical and morphological characteristics of NiO and can be used for various applications.