Structural, optical and electrochemical properties of Sr-doped ZnO nanoparticles

The Sr-doped ZnO nanoparticles have been synthesized by the chemical precipitation method at room temperature. The prepared nanoparticles are annealed at 500 °C for 4 h. The nanoparticles have been characterized using X-ray diffraction (XRD) technique, scanning electron microscope and UV–Vis spectroscopy. The XRD studies reveal the formation of a wurtzite geometry. The crystallite size, dislocation density and strain are examined as a function of Sr-doping concentration. The band gap of the prepared nanoparticles ranges from 3.46 eV to 3.56 eV. The nanoparticles have a higher hole concentration than electron concentration. Supercapacitor cells have been prepared by using synthesized nanoparticle electrodes and it is characterized using cyclic voltammetry (CV) by using KOH as an electrolyte solution. The calculated specific capacitance is high at a high doping concentration of ‘Sr’. [Display omitted] •Wurtzite geometry undoped ZnO and Sr-doped ZnO nanoparticles have been prepared.•The crystallite size of the nanoparticles ranges from 28.46 to 33.45 nm.•The optical absorbance is enhanced due to doping and the observed band gap is blue-shift due to addition of the dopants.•The nanoparticles have high hole concentration and the charge carrier concentration increases at high doping concentration.•The high specific capacitance 500 F/g is observed in this study which corresponds to the Sr-doped ZnO (4 %) nanoparticles.