Linear and nonlinear optical properties of ultrafine WO3 nanorods

WO3 nanorods were obtained via hydrothermal synthesis using sodium tungstate as a pre-cursor and cetyltrimethylammonium bromide as a stabilizing agent. Trnsmission electron microscopy images confirmed the successful formation of ultrafine nanorods by this facile method. X-ray diffraction indicated the presence of hexagonal phase WO3. The linear optical properties of the WO3 nanorods were determined by UV/Vis spectroscopy and the calculated results showed that their band gap is blue-shifted compared to the bulk WO3 value. This may be attributed to the quantum confinement effect. The nonlinear optical (NLO) properties of the obtained WO3 nanorods were characterized by an open aperture Z-scan technique with 4 ns laser pulses at 532 nm. These WO3 nanorods displayed improved NLO properties with an increase in the irradiated intensity, meaning that they could potentially be used in photonic or optoelectronic devices to protect human eyes or to inhibit damage to optical sensors from intense laser irradiation. (C) 2017 Elsevier GmbH. All rights reserved.