A novel technique was demonstrated for the growth of CuInSe2 (CIS) thin films. The technique used an ink formulation containing sub-micron size particles of Cu-In alloys. A metallic precursor layer was first formed by coating this ink onto the substrate by spraying. The precursor film was then made to react with Se to form the CIS compound. The morphology of the CIS layers depended on the initial composition of the Cu-In particles as well as the post-deposition treatments. Solar cells were fabricated on CIS absorber layers prepared by this low-cost ink-coating approach and devices with a conversion efficiency of over 10.5% were demonstrated. (C) 2000 Elsevier Science B.V. All rights reserved.