PEG induced tunable morphology and band gap of ZnO

We demonstrate the fabrication ZnO nanostructures with tunable morphology and band gap by polyethylene glycol (PEG) assisted microemulsion strategy. Rectangular and spindle-like ZnO nanoparticles were obtained for PEG 200, 400 and 1000, while ZnO nanorods were achieved by PEG 10000. The formation mechanism was discussed correspondingly. XRD and PL spectra reveal that the defects in ZnO products are enhanced with PEG molecular weight increasing from 200 to 10000, resulting in the band gap energies decreasing from 3.12 eV to 2.95 eV, as demonstrated in the UV-Vis absorption spectra. The present research work can provide a new way to tune the optical property of ZnO.