Nanoparticulate film precursors to cis solar cells: Spray deposition of Cu-In-Se colloids

Abstract

ABSTRACTThe use of nanoparticle colloids for spray deposition of Cu-In-Se precursor films and subsequent thermal treatment to form CuInSe2 (CIS) films has been investigated. In the present study, the metathesis reaction between Na2Se in methanol and metal salts (i.e., Cu(BF4)2 and/or InI3) in pyridine produced CuSe, In2Se3, and CuInSe2.5 nanoparticle colloids. Purified colloid was sprayed onto heated molybdenum-coated sodalime glass substrates to form CuInSe2.5/Mo and In2Se3/CuSe/Mo precursor films. These precursor films were subjected to various thermal treatments in an effort to produce large-grained CIS films from the nano-sized precursors. The annealed CIS films were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Results of this continuing effort will be discussed.