Micro-Raman and photoluminescence analysis of composite vanadium oxide/poly-vinyl acetate fibres synthesised by electro-spinning

Composite vanadium oxide (VOx)-based fibres were synthesised by the electro-spinning method combined with conventional solgel processing using polyvinyl acetate (PVAc) as a polymeric binder and vanadium oxytriisopropoxide as a vanadium oxide precursor. The microstructure and composition of as-spun and calcined (300-500 degrees C) VOxPVAc fibres were systematically investigated by scanning electron microscopy, thermogravimetry, reflectance infrared Fourier transform, micro-Raman spectroscopy and photoluminescence in view of their possible use in gas sensor fabrication. The comparative discussion of the characterization results indicates that V2O5PVAc fibres are obtained. Calcination gradually removes PVAc and promotes structural rearrangement with consequent fibre-morphology changes. With increasing calcination temperature, the crystallinity degree of V2O5 improves and a more oxygen-deficient substoichiometric surface layer forms. Calcination at 400 degrees C preserves the fibre integrity. Indeed, fibres calcined at this temperature appear as the most suitable ones for use as the active layer in gas-sensing devices. Copyright (C) 2011 John Wiley & Sons, Ltd.