Electrodeposited α- and β-Phase MoO3 Films and Investigation of Their Gasochromic Properties

alpha- and beta-Phase MoO3 are synthesized using an electrodeposition method on fluorine-doped tin oxide (FTO) glass substrates from sodium-molybdate (Na2MoO4) solutions. We show that it is possible to obtain both alpha- and beta-MoO3 by manipulating the cyclic voltammetry (CV) parameters during electrodeposition. Raman spectroscopy, X-ray diffraction, and scanning electron microscopy indicate that the applied potential range and sweep rate are strongly influential on the phase obtained and the surface morphology of the electrodeposited thin films. Gasochromic measurements were carried out on the annealed samples by exposing them to H-2 gas. It was revealed that alpha-MoO3 thin films provided better response to H-2 interaction than beta-MoO3 films did. Additionally, porous films provided significantly larger responses than smooth films.