NOVELTY - Fabricating thin film photovoltaic absorber layer (63) involves providing nanoparticles containing combination of copper (Cu), group IIIA element and optionally group VIA element in predetermined ratio, or combination of Cu, group IIB element, group IVA element, and optionally group VIA element of periodic table in predetermined ratio; forming colloidal suspension of the mixture of nanoparticles in liquid medium; and submerging substrate and counter electrode into colloidal suspension and depositing mixture of nanoparticles onto substrate by electrophoretic deposition.    USE - For fabricating thin film photovoltaic absorber layer useful in multilayer photovoltaic device (claimed).    ADVANTAGE - The method is simple and cost-effective; has minimal impurity contamination; provides high quality and process controllability; maximizes source material usage; and reduces process complexity. The method requires minimum chemical additives during both formation of the nanoparticles and the subsequent coating of the nanoparticles onto a substrate to form the absorber layer. The method must ensure that the resultant absorber layer contains the desired chemical composition.    DETAILED DESCRIPTION - Fabricating thin film photovoltaic absorber layer (63) involves providing nanoparticles containing a combination of either Cu and at least one group IIIA element, and optionally at least one group VIA element, or combination of Cu, at least one group IIB element and at least one group IVA element, and optionally at least one group VIA element of the periodic table; preparing a colloidal suspension of a mixture of the nanoparticles in liquid medium, where the atomic ratio between Cu and group IIIA and optional group VIA elements and between Cu and group IIB and group IVA elements and optional group VIA elements are predetermined; and submerging a substrate and a counter electrode into the colloidal suspension and depositing the mixture of nanoparticles onto the substrate to form thin film photovoltaic absorber layer by electrophoretic deposition, where the predetermined atomic ratio between Cu and group MA and optional group VIA elements or between Cu and (group HB plus group IVA elements) and optional group VIA elements is 25%:25%:50% plus minus 15%. An INDEPENDENT CLAIM is included for multilayer photovoltaic device comprising conductive substrate or supporting substrate (61) coated with conductive back electrode (62); thin film photovoltaic absorber layer prepared by the method; a window layer (64) containing cadmium sulfide; and a transparent electrode (65) comprising zinc oxide, optionally doped with aluminum, overlayed with a metallic top contact (66).    DESCRIPTION OF DRAWING(S) - The figure shows schematic diagram of photovoltaic cell.    Supporting substrate (61)    Back electrode (62)    Photovoltaic absorber layer (63)    Window layer (64)    Transparent electrode (65)    Top contact (66)