Structural, optical, antimicrobial and ferromagnetic properties of Zn1−xLaxO nanorods synthesized by chemical route

•Crystal structure of the ZnO nanorods was not affected by La doping.•Band gap of ZnO nanorods increased with increasing La doping.•Appearance of strong emission in the UV region suggested the useful of these materials for UV light emission devices.•Presences of various intrinsic defects were identified through PL spectra.•Occurrence of ferromagnetism in the samples was explained on the basis of a BMP model.•ZnO nanorods showed low toxicity against Caenorhabditis elegans at 100 µg/mL, while with Danio rerio 1% La-doped ZnO showed paralytic activity.•ZnO nanorods could be useful for multifunctional devices like optoelectronics, spintronics as well as for biomedical applications. Nanoparticles of Zn1−xLaxO (x = 0, 0.01, 0.03 and 0.05) were successfully synthesized by a cost-effective chemical method. The influences of La on the microstructural, optical, antimicrobial and magnetic properties of these ZnO nanoparticles were investigated. XRD studies revealed the presence of hexagonal wurtzite phase of ZnO without any impurity. The samples possess nanorod morphology as confirmed by FESEM and TEM analysis. The band gap of ZnO nanorods increased from 3.25 to 3.27 eV with increasing La concentration from 0% to 5%. The presence of various defects in our samples were identified by PL spectroscopy. Magnetic studies exposed the signature of ferromagnetism in all the samples at 300 K. The magnetization of ZnO nanorods is significantly enhanced by La doping. A maximum values of magnetization was observed for 1% La doped ZnO sample which is ~6 times more than for a pure ZnO nanorods. The contributions of oxygen vacancies towards the observed ferromagnetism were confirmed. The origin of ferromagnetism was enlightened on the basis of results of a BMP model. In vitro bioassays showed that synthesized nanorods exhibited narrow-spectrum antibacterial activity against Staphylococcus aureus that compared well with commercial ZnO, nanoparticles (Sigma). Furthermore, the synthesized nanorods when tested for toxicity against Caenorhabditis elegans, but show only low toxicity at 100 µg/mL. Toxicity in zebrafish was also limited. Based on their multifunctional properties, we believe that the synthesized ZnO nanorods could be beneficial for optical device applications in the UV range, spintronic devices, as well as for biomedical purposes.