1 23 Journal of Sol-Gel Science and Technology ISSN 0928-0707 Volume 65 Number 2 J Sol-Gel Sci Technol (2013) 65:178-188 DOI 10.1007/s10971-012-2922-4 Photocatalytic activities of multilayered ZnO-based thin films prepared by sol–gel route: effect of SnO 2 heterojunction layer Nasrin Talebian, Mohmmad Reza Nilforoushan & Parisa Memarnezhad