Tuning of Photoluminescence and Antibacterial Properties of ZnO Nanoparticles through Sr Doping for Biomedical Applications

Abstract

Sr-doped ZnO nanoparticles have been synthesized using a soft chemical method. The doping ratio of Sr is varied in the range of 0 at.%, 3 at.%, and 5 at.% to 7 at.%. X-ray diffractograms revealed that the samples had hexagonal (wurtzite) structure without a trace of any mixed phase. The average crystallite size of the nanoparticles (NPs) ranged from 39 to 46 nm. The average crystallite size was increased for the initial doping (3 at.%) of Sr ions, and further increase in the doping ratio reduced the particle size due to some distortion produced in the lattice. The surface morphology of the samples and structure of the NPs were investigated using FESEM (Field Emission Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy) pictures, respectively. EDX (energy-dispersive X-ray) spectroscopy confirmed the presence of strontium (Sr) in the host lattice. Photoluminescence and X-ray diffraction confirmed that the dopant ions replace some of the lattice zinc ions and that Sr2+ and Sr3+ ions coexist in the ZnO lattice. The Sr-doped ZnO exhibited violet and blue luminescence spectra at 408 nm and 492 nm, respectively. ZnO : Sr nanoparticles showed increased antibacterial activity against one gram-positive as well as one gram-negative bacteria.

Photoluminescence and antibacterial performance of sol–gel synthesized ZnO nanoparticles

“…The increase in emission implies that the possibility of recombination of free excitons increases due to thermal annealing. 12,27 During the annealing process, because of the separation of donor bond excitons into free excitons, the recombination rate is increased.…”

“…The increase in emission implies that the possibility of recombination of free excitons increases due to thermal annealing. 12,27 During the annealing process, because of the separation of donor bond excitons into free excitons, the recombination rate is increased. Further, it is observed that after annealing at 350 1C, an intense blue PL band is exhibited at around 468.9 nm from the crystalline ZnO NPs.…”

“…10 The performance of NPs also depends on the surface area and surface defects, which may introduced by the dopant material and post-treatment that are responsible for the enhancement in the properties of NPs. [10][11][12] An enhancement in properties without any change in the structural properties of the host matrix has significant importance. It has been reported that doping and other treatments may also enhance the properties of ZnO nanomaterials without any changes in the structural unit, and they may also be capable of improving the quality of the nanomaterials.…”

“…10 The performance of NPs also depends on the surface area and surface defects, which may introduced by the dopant material and post-treatment that are responsible for the enhancement in the properties of NPs. 10–12…”

Structural, Morphological, Optical, and Antibacterial Activities of Zinc Oxide Nanopowders: A Comparative Study of Green and Soft Chemical Synthesis

“…In earlier research, enhanced bacteria-killing capacity was discussed in ZnO nanoparticles [11]. Many researchers have examined and reported the antibacterial activity of ZnO [12,13].…”