Coprecipitation synthesis of Ni-doped SnO2 nanostructures and study of their structural, optical, and dielectric properties

Abstract

In this study, the dielectric and optical characteristics of low-dimensional pristine SnO₂ and SnO₂ doped with various nickel concentrations, grown through the coprecipitation method, are investigated. All the prepared samples demonstrate tetragonal phase according to the XRD results. The XRD pattern also shows that as the amount of the dopant increases, both the crystallite size and crystallinity decrease while the microstrain increases. The spherical morphological structure is made clear by SEM pictures. Consequently, elemental concentrations of tin, oxygen, and nickel in pristine samples and tin, oxygen, and nickel in all doped samples are shown by EDX. The EDX result indicates also that as the amount of nickel dopants increases, the oxygen concentration decreases and the SnO₂ sample becomes oxygen deficient. This results in more vacancies forming into the SnO₂ lattice. FTIR is used to study the vibrational modes of SnO₂. The UV–Vis reveals that with increasing the Ni content, the absorbance rises, i.e., the samples doped with 5 wt.% Ni demonstrate the highest absorbance. There are higher oxygen vacancies (defect density) in the sample weighing 5 wt.%. The dielectric constant is found to be distributed due to the small size of the crystallites and the increased hopping mechanism between Ni²⁺ and Ni³⁺. The best sample for storage devices is the one with 5-wt.% nickel, as indicated by the decrease in dielectric loss that occurs with an increase in nickel content. However, as the Ni content rises to 5 wt.%, Ni-doped SnO₂ exhibits an improvement in conductivity at higher frequencies, making it a suitable material for high-frequency devices.