Sol-gel derived Al-doped ZnO nanoplates: Structural and optical properties

Abstract

In the present work, undoped and Al-doped ZnO nanoplates have been prepared by sol–gel method and investigated their structural, morphological and optical properties. Structural analysis has been performed by powder X-ray diffraction (XRD) pattern. The XRD results exhibited that the synthesized nanostructures have hexagonal wurtzite phase of ZnO. Scanning electron microscopy (SEM) depicts the formation of nanoplates. The optical properties of the prepared samples have been studied using UV–visible (UV–vis) absorption and photoluminescence (PL) spectroscopy at 300 K. UV–vis absorption spectra revealed a large blue shift in absorption peak indicates quantum size confinement effect. Red-shifted absorbance peak is obtained for higher doping concentration of Al that may be attributed to change of the surfaces for nanoplates. PL spectra of undoped and Al-doped ZnO NPs have band edge luminescence in UV region and defects related optical emission such as violet emission at ~417 nm, blue emission at ~441 nm, blue–green emission at ~484 nm and green emission at ~524 nm in visible region. A significant enhancement of the PL intensity has been observed in 3 wt% Al-doped ZnO sample as compared to undoped ZnO which may be assigned to transformation of nanoclusters to nanoplates.