Synthesis and optical properties of nanocrystalline V-doped ZnO powders

Abstract This paper reports the synthesis and optical properties of nanocrystalline powders of V-doped ZnO (i.e. Zn 0.95 V 0.05 O, Zn 0.90 V 0.10 O, and Zn 0.85 V 0.15 O) by a simple sol–gel method using metal acetylacetonates of Zn and V and poly(vinyl alcohol) as precursors. Structure of the prepared samples was studied by X-ray diffraction, FTIR spectroscopy, and selected-area electron diffraction (SAED) analysis. The morphology of the powders revealed by SEM and TEM was affected by the amount of V, causing the formations of both nanoparticles and nanorods in the Zn 0.95 V 0.05 O sample, nanorods in the Zn 0.90 V 0.10 O sample, and nanoparticles in the Zn 0.85 V 0.15 O sample. The optical properties of the samples were investigated by measuring the UV–VIS absorbance and photoluminescence spectra at room temperature. All the samples exhibited UV absorption at below 400 nm (3.10 eV) with a well-defined absorbance peak at around 364 nm (3.41 eV) and 288 nm (4.31 eV). The band gap of the V-doped samples shows a decrease with increasing V concentration. The photoluminescence spectra of all the samples showed a strong UV emission band at ∼2.98 eV, a weak blue band at 2.82 eV, a week blue–green band at 2.56 eV, and a weak green band at 2.34 eV, which indicated their high structural and optical quality.