Structural, morphological, optical and antibacterial performances of rare earth (Sm)-doped ZnO nanorods

Abstract

The significant rise of ultra-violet (UV) radiation and pathogenic infectious bacteria poses a serious threat to global health. Numerous researchers’ interests are attracted by novel materials with strong UV-blocking ability, antibacterial activity and low toxicity to other species. In this case, a simple wet chemical method with different annealing temperatures (400, 500, and 600 °C) was employed to create highly effective rare earth (Sm)-doped ZnO nanorods. The (101) plane of wurtzite ZnO shifts towards a lower angle with increasing annealing temperature, according to the X-ray diffraction (XRD) study findings, which additionally establishes the consequence of lattice expansion. Occurrence of doublet peaks of Sm 3d (Sm 3d5/2 and Sm 3d3/2) in the X-ray photoelectron spectroscopy (XPS) spectrum clearly validates the substitution of Sm3+ ions in the 500 °C-annealed samples. The 500 °C-annealed nanorods exhibit combined performances of the wide band gap, improved UV absorbance, and vivid green luminescent emission (563 nm). Additionally, the nanorods have favorable UV-blocking execution of 96 % for UVA at 360 nm, 92 % for UVB at 320 nm, and 57 % for UVC at 225 nm, which is greater than the majority of ZnO-related materials that have been reported up to this date. Sm doping is also appropriate for improving bacterial inhibition against the two studied strains (Escherichia coli and Staphylococcus aureus), in addition to the intriguing features discussed above. Furthermore, with maximum inhibition zone diameters of 20 ± 0.72 and 18 ± 0.57 mm, respectively, these nanorods exhibit high inhibitory action against E. coli and S. aureus bacterial strains. The rare earth-doped material developed during the current experiment, which was annealed at 500 °C, could potentially serve as an effective replacement for UV-blocking and antibacterial material, especially for biomedical applications.