Solar Energy Materials & Solar Cells 90 (2006) 2894–2907 Sol–gel deposition and optical characterization of multilayered SiO 2 /Ti 1x Si x O 2 coatings on solar collector glasses Andreas Schu¨ler a,Ã , Deepanshu Dutta b , Estelle de Chambrier a , Christian Roecker a , Gregory De Temmerman c , Peter Oelhafen c , Jean-Louis Scartezzini a a Ecole Polytechnique Fe´de´rale de Lausanne EPFL, Baˆtiment LE, 1015 Lausanne, Switzerland b Physics Department, Indian Institute of Technology IIT, Hauz Khas New Delhi 110 016, India c Institute of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland Received 29 January 2006; accepted 14 May 2006 Available online 26 July 2006 Abstract Thin films of silicon oxide and silicon titanium mixed oxides are deposited on solar collector glazing in a sol–gel dip-coating process based on alcoxide precursors. Spectrophotometry is used to characterize the relation of film thickness and withdrawal speed for the precursor solutions, and to determine the refractive index of individual layers of the mixed oxides. The inferred dispersion relations nðlÞ are compared to the predictions of effective medium theories. Based on the knowledge of the optical properties of individual layers, multilayer interference stacks are designed. Multilayered samples of superior quality are deposited by sol–gel dip-coating in a particle-free environment. The final optical performance of the multilayer stacks are characterized in terms of the visible reflectance R VIS , CIE color coordinates, and the solar transmission T sol . Values of up to 2.4 have been attained for the energy efficiency of the colored reflection M ¼ R VIS =ð100%  T sol Þ. The produced coatings combine a bright colored reflection with an acceptable solar transmittance, and are thus well suited for the application in colored glazed thermal solar collectors. This novel type of colored glazing opens up new perspectives for the architectural integration of thermal solar collectors, e.g. as solar active glass facades. r 2006 Published by Elsevier B.V. Keywords: Sol–gel dip-coating; Nanocomposite thin films; Solar collector glazing; Multilayer interference stacks; Colored solar collectors ARTICLE IN PRESS www.elsevier.com/locate/solmat 0927-0248/$ - see front matter r 2006 Published by Elsevier B.V. doi:10.1016/j.solmat.2006.05.003 Ã Corresponding author. Tel.: +41 21 693 4544; fax: +41 21 693 2722. E-mail address: andreas.schueler@epfl.ch (A. Schu¨ler).