Unravelling the effect of Ni doping on the structural, optical and dielectric properties of nanocrystalline SnO2

•Single phase Ni doped SnO2 samples are synthesized via sol-gel process.•The crystallite size is found to increase with the increase in Ni content.•A systematic decrease in bandgap is noticed in Ni doped samples.•On doping of Ni concentration, dielectric constant decreases.•Content of doping plays a vital role in controlling the physical properties of SnO2.