Structural and optical properties of visible active photocatalytic WO3 thin films prepared by reactive dc magnetron sputtering
2012 (English)In: Journal of Materials Research, ISSN 0884-2914, Vol. 27, no 24, 3130-3140 p.Article in journal (Refereed) Published
Nanostructured tungsten trioxide films were prepared by reactive dc magnetron sputteringat different working pressures P-tot = 1-4 Pa. The films were characterized by scanning electron microscopy, x-ray diffraction, Rutherford backscattering spectroscopy, Raman spectroscopy, and ultraviolet-visible spectrophotometry. The films were found to exhibit predominantly monoclinic structures and have similar band gap, E-g approximate to 2.8 eV, with a pronounced Urbach tail extending down to 2.5 eV. At low P-tot, strained film structures formed, which were slightly reduced and showed polaron absorption in the near-infrared region. The photodegradation rate of stearic acid was found to correlate with the stoichiometry and polaron absorption. This is explained by a recombination mechanism, whereby photoexcited electron-hole pairs recombine with polaron states in the band gap. The quantum yield decreased by 50% for photon energies close to E-g due to photoexcitations to band gap states lying below the O-2 affinity level.
Place, publisher, year, edition, pages
2012. Vol. 27, no 24, 3130-3140 p.
Nano Technology Condensed Matter Physics Materials Chemistry
Research subject Engineering Science with specialization in Nanotechnology and Functional Materials; Engineering Science with specialization in Solid State Physics
IdentifiersURN: urn:nbn:se:uu:diva-187494DOI: 10.1557/jmr.2012.384ISI: 000312394400012OAI: oai:DiVA.org:uu-187494DiVA: diva2:574883
FunderSwedish Research Council, 2010-3514