Structural, opto-electronic, and photocatalytic properties of some pure and Al/Ni modified ZnO

Abstract

Zn1−x(Al0.5Ni0.5)x O(x = 0, 0.0078, 0.0156, 0.0234, 0.03125) nanoparticles have been synthesized by using a simple sol-gel route. ZnO generally crystallizes in three forms: hexagonal wurtzite, cubic Zinc Blende and rock salt structure. According to the first principle, periodic Hartree-Flock linear combination of atomic orbitals theory, the hexagonal Zinc wurtzite is found to be the most thermodynamically stable form. It was observed from XRD studies. A Rietveld analysis of the XRD spectra using GSAS software helped evaluate the variations of lattice constant, lattice strain, lattice parameter around a = b = 3.25 ˚A, c = 5.20 ˚A of pure ZnO and doped one. With Al/Ni doping, while the direct bandgap could be nominally tuned from ∼ 3.247 eV to ∼ 3.273 eV, the Al/Ni doping seems to improve carrier concentration, mobility, and lattice regularity than pure ZnO. The photocatalytic degradation of toxic methylene blue (MB) dye could be enhanced from 0.560 ≤ x ≤ 3.125% Al/Ni doped ZnO. This property has been correlated to the carrier properties of the materials. This n-type is due to the structural point defect (vacancies and interstitials) and extended defects (threading/planar dislocations).