Effects of Tin Doping Concentration on the Structural and Optical Properties of Cadmium Oxide Nanoparticles

Abstract

Wet chemical process was successfully used to synthesize tin doped and undoped cadmium oxide nanoparticles. Cadmium acetate, sodium hydroxide, mercaptopropionic acid and tin chloride were used as starting materials for synthesizing the nanoparticles. The reaction was carried out in a single three-necked flask under reflux at 80°C for 2 hours and the solution was allowed to cool to room temperature. The precipitate was washed, dried, annealed and grounded to obtain the powder for further analysis. The phase and structure of the nanoparticles was studied using the X-ray diffraction equipment. Debye Scherrer’s equation was used to calculate the crystallite sizes of the doped and undoped nanoparticles. The XRD pattern displayed face centered cubic structure of cadmium oxide. When CdO was doped with Sn the intensity peaks decreased from 1650 a. u for pure CdO to 1235 a. u at 1% Sn doped and at 3.5% Sn doped, the intensity peak was 239 a. u. Increase in the doping concentration resulted in significant increase in grain size. Optical properties investigated for different doping concentration of tin showed that all the samples exhibited the well-defined absorption bands in the range of 298 nm to 340 nm. The bandgap energy was found to be 3.69 eV for pure CdO and a realistic decrease when doped. The corresponding PL spectra with the excitation wavelength of 320 nm displayed a narrow emission at 429 nm. The obtained results displayed good material properties of the NPs suitable for possible solar cell applications.