Structural and Optical Properties of Bismuth-doped ZnO Nanoparticles Synthesized by Co-precipitation

Bismuth-doped zinc oxide (ZnO) nanoparticles can serve as efficient photocatalysts for various reactions. Herein, we synthesized and discussed the growth mechanisms of Bi-doped ZnO nanoflakes using co-precipitation with Bi concentrations ranging from ۰ to ۳ %. The resulting ZnO were hexagonal nanosheets with diameters ranging from ۸۰ nm (ZnO) to ۲۰۰ nm (ZnO: Bi ۳%). The dominant crystal structure matches hexagonal wurtzite with a small presence of Bi۲O۳ diffraction peaks. The estimated crystallite sizes range from ~ ۳۳ nm to ~ ۴۵ nm, indicating multiple crystalline regions in each nanoflake. Nevertheless, as sheet resistance monotonically decreases with the Bi concentration, the higher number of grain boundaries likely has a lower effect on the conductivity compared to an increase in free carriers and larger grain size in the samples with higher Bi concentration. The bandgap decreases from ~ ۳.۱۳ eV to ~ ۲.۹۶ eV, likely due to the shrinkage effect from electron-electron or electron-impurity interaction that lowers the conduction band of ZnO.

Keywords:

Zinc oxide nanoparticles , bismuth-doped ZnO , Co-precipitation , Photo-catalyst