NOVELTY - The method comprises depositing an ohmic contact layer over a sheet shaped substrate (11), depositing a seed layer including copper over the ohmic contact layer, electrodepositing a precursor in one layer, reacting the precursor with Group VIA material to form the Group IBIIIAVIA absorber layer, depositing a transparent layer (14) over the Group IBIIIAVIA absorber layer, depositing a nucleation layer on the ohmic contact layer, and forming electrical contacts on the transparent layer. The precursor includes a Group IB material, and Group IIIA material.    USE - The method is useful for forming a thin film solar cell such as photovoltaic devices having a Group IBIIIAVIA absorber layer.    ADVANTAGE - The method is capable of effectively and rapidly forming the thin film solar cell with improved conversion efficiency and lifespan and high quality thus ensuring economical generation of electricity.    DETAILED DESCRIPTION - The method comprises depositing an ohmic contact layer over a sheet shaped substrate (11), depositing a seed layer including copper over the ohmic contact layer, electrodepositing a precursor in one layer, reacting the precursor with Group VIA material to form the Group IBIIIAVIA absorber layer, depositing a transparent layer (14) over the Group IBIIIAVIA absorber layer, depositing a nucleation layer on the ohmic contact layer, and forming electrical contacts on the transparent layer. The precursor includes a Group IB material, and Group IIIA material, where the precursor as-deposited has a Group IB to Group IIIA molar ratio of less than or equal to 1. The ohmic contact layer is a made of metal-nitride, and a metal. The step of depositing the seed layer includes atomic layer deposition, chemical vapor deposition, metal-organic chemical vapor deposition and physical vapor deposition. A thickness of the seed layer is 2-100 nanometers. The step of depositing the nucleation layer comprises electroplating, electroless plating, atomic layer deposition, chemical vapor deposition, metal-organic chemical vapor deposition and physical vapor deposition. The reaction step comprises heating the precursor in a gas containing selenium, depositing a selenium layer on the precursor thus forming a precursor/selenium stack, and heating the stack. The sheet shaped substrate comprises a stainless steel foil, and a molybdenum foil.    DESCRIPTION OF DRAWING(S) - The diagram shows a cross-sectional view of a solar cell having a Group IBIIIAVIA absorber layer.    Substrate (11)    Absorber film (12)    Conductive layer (13)    Transparent layer (14)    Radiation. (15)