Investigating the effects of Fe dopant on structural, optical, and photocatalytic properties of ZnO nanoflowers

Fe-doped ZnO nanostructures with various concentrations of Fe dopant (from 0 to 5 at.%) were synthesized by using a simple one-stage hydrothermal method. The structural characterization of the samples shows that Fe2+ is substituted in the cationic sites of ZnO wurtzite lattice structure. The optical band gap of the samples was a little decreased by increasing the concentration of Fe dopant (from 3.21 eV for bare ZnO to 2.92 eV for 5 at.% Fe-doped ZnO). This observation implies the formation of shallow levels within optical band gap and is confirmed by relative extinction of photoluminescence peaks with increasing the Fe content. On the other hand, the regular in shape nanoflowers seem to be the best choice for good light harvesting. Concerning the aforesaid affecting parameters, one can conclude that there must be an optimal concentration of Fe for having the maximum photocatalytic performance which was obtained to be 2 at.% Fe by photocatalytic tests.