Gold Decoration and Photoresistive Response to Nitrogen Dioxide of WS2 Nanotubes.
Composites of WS2 nanotubes (NT-WS2 ) and gold nanoparticles (AuNPs) were prepared using aqueous HAuCl4 solutions and subjected to surface analysis. The obtained materials were jointly characterized by X-ray photoelectron (XPS), Raman scattering (RSS), and ultraviolet photoelectron (UPS) spectroscopies. Optical extinction spectroscopy and electron energy loss spectroscopy in the scanning transmission electron microscopy regime (STEM-EELS) were also employed to study plasmon features of the nanocomposite. It was found that AuNPs deposition is accompanied by a partial oxidative dissolution of WS2 , whereas Au-S interfacial species could be responsible for the tight contact of metal nanoparticles and the disulfide. A remarkable sensitivity of n-type resistance of NT-WS2 and Au-NT-WS2 to the adsorption of NO2 gas was also demonstrated at room temperature using periodical illumination by a 530 nm light-emitting diode. Au-NT-WS2 nanocomposites are found to possess a higher photoresponse and enhanced sensitivity in the 0.25-2.0 ppm range of NO2 concentration, as compared to the pristine NT-WS2 . This behaviour is discussed within the physisorption-charge transfer model to explore sensing properties of the nanocomposites.
['Polyakov|Alexander Yu|AY|http://orcid.org/0000-0002-3781-1881', 'Kozlov|Daniil A|DA|', 'Lebedev|Vasily A|VA|http://orcid.org/0000-0003-4703-5780', 'Chumakov|Ratibor G|RG|', 'Frolov|Alexander S|AS|', 'Yashina|Lada V|LV|http://orcid.org/0000-0002-8370-9140', 'Rumyantseva|Marina N|MN|http://orcid.org/0000-0002-3354-0885', 'Goodilin|Eugene A|EA|']
WS2 nanotubes gold nanoparticles STEM-EELS X-ray photoelectron spectroscopy nitrogen dioxide sensing