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We report for the first time the synthesis of monoclinic WO3 quantum dots. A solvothermal processing at 250 °C in oleic acid of W chloroalkoxide solutions was employed. It was shown that the bulk monoclinic crystallographic phase is the stable one even for the nanosized regime (mean size 4 nm). The nanocrystals were characterized by X-ray diffraction, High resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV–vis, Fourier transform infrared and Raman spectroscopy. It was concluded that they were constituted by a core of monoclinic WO3, surface covered by unstable W(V) species, slowly oxidized upon standing in room conditions. The WO3 nanocrystals could be easily processed to prepare gas-sensing devices, without any phase transition up to at least 500 °C. The devices displayed remarkable response to both oxidizing (nitrogen dioxide) and reducing (ethanol) gases in …
American Chemical Society
Publication date: 
8 Oct 2014

Mauro Epifani, Elisabetta Comini, Raül Díaz, Teresa Andreu, Aziz Genc, Jordi Arbiol, Pietro Siciliano, Guido Faglia, Joan R Morante

Biblio References: 
Volume: 6 Issue: 19 Pages: 16808-16816
ACS applied materials & interfaces