Experimental and DFT study of Al doped ZnO nanoparticles with enhanced antibacterial activity

Abstract

In this work, Al doping induced effects on the crystal structure, electronic band structure and photoluminescence properties of chemically synthesized ZnO nanoparticles are investigated. Our experimental findings suggest that Al ions are successfully doped into ZnO host matrix resulting in tuning of optical band gap and photoluminescence properties. To further verify and support our experimental results we performed the computational analysis employing first-principle calculations based upon density functional theory. We studied the effects of substitutional doping of Al on Zn-site in 3×3×1 supercell of wurtzite ZnO crystal structure with different concentration levels 2.7% and 5.5% on structural and electronic properties. The formation energy calculations show that the ZnO crystal structure is thermally stable and also via Al doping the stability got enhanced. We found that the lattice constant of Al-doped ZnO crystal structures slightly decreased due to which the electronic band gap is increased consistent with our experimental results. Also, we demonstrated that the band gap is tuned to a larger value via Al doping at the cation site in the wurtzite ZnO crystal structure. We found that Al doping play an important role in the enhancement of the electronic properties. Finally, the antibacterial tests indicate the enhanced antibacterial activity of Al doped ZnO nanoparticles which may be attributed to the improved structural, optical and photoluminescence properties.