Al2O3 nanoparticle polymorphs: effects of Zn2+ doping on the structural, optical and cytotoxic properties

Al2O3-Zn x% NPs, with x = 0, 1, 3, 5 or 10 mol% Zn2+ were synthesized by a modified sol-gel method. The influence of the insertion of Zn2+ dopant on the crystal lattice, morphology, optical and cytotoxic properties of Al2O3 was investigated. Rietveld refinement applied to DRX data revealed that the oxides are constituted by four crystalline phases: alpha -Al2O3, theta -Al2O3, delta -Al2O3 and alpha -Al2O3(*), and that the doping promoted changes in unit cell volume for all the crystalline phases. Raman signals indicated that the insertion of Zn2+ caused changes in the vibrations of bonds Al-O, mainly in tetrahedral sites of transition phases of Al2O3, which are preferentially occupied by Zn ions. The oxides exhibited photoluminescence emission in the visible and near-infrared region, but Al2O3-Zn 10% showed increased emission intensity in the visible region. The nanoparticles with spherical and elongated morphologies did not exhibit cytotoxic effects on L929 fibroblast cells.Graphic abstractZn-doped Al2O3 nanoparticles were synthesized by a modified sol-gel method. The influence of the insertion of Zn2+ dopant on the crystal lattice, morphology, optical and cytotoxic properties of Al2O3 was investigated.

Automated summary

Zn-doped Al2O3 nanoparticles were synthesized by a modified sol-gel method, and the influence of Zn2+ dopant on the crystal lattice, morphology, optical, and cytotoxic properties of Al2O3 was investigated. The study found changes in unit cell volume, vibrational bonds, and photoluminescence emission in the Al2O3-Zn nanoparticles, with no cytotoxic effects observed on fibroblast cells.