NOVELTY - A thin film solar cell (10) comprises: a sheet-shaped substrate (11); a conductive layer (13) disposed over the substrate; an absorber layer (12) disposed over the conductive layer, where the absorber layer includes at least one Group (IB) material, at least one Group (IIIA) material, and at least one Group (VIA) material; and an additional layer (14) disposed over the absorber layer, where one of the conductive layer and the additional layer includes at least one of ruthenium, osmium and iridium.    USE - As a solar cell (claimed) useful for converting sunlight directly into electrical power.    ADVANTAGE - The solar cell has improved contact layers or nucleation layers over which precursors and thin films of the compounds adhere well to form high quality layers with excellent micro-scale compositional uniformity, thereby increasing solar cell efficiency. The method of forming of layers is flexible and involves wet deposition techniques such as electroplating with large degree of freedom in terms of deposition sequence of different layers forming various metallic stacks, and also addresses the issues of adhesion and yield.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) producing a solar cell involving: (a) forming a conductive layer over a top surface of a sheet-shaped base; (b) forming an absorber layer over the conductive layer, including the steps of: depositing a set of distinct layers over a top surface of the conductive layer, the set of distinct layers including at least four layers, with two of the layers being a pair of non-adjacent layers made of one of Cu, In and Ga, and the other two layers being made of the remaining two of the Cu, In and Ga; and treating the set of distinct layers to form the absorber layer; and (c) forming an additional layer over the absorber layer, where one of the steps of forming the conductive layer and forming the additional layer includes at least one of Ru, Ir, and Os in the conductive layer and the additional layer, respectively; and    (2) forming a Cu(In, Ga)(Se, S)2 absorber layer involving: (a) applying, over a sheet-shaped base, a conductive layer comprising at least one of Mo, Ru, Ir and Os; (b) electrodepositing discrete layers in sequence to form a precursor stack over the conductive layer, each discrete layer comprising one of Cu, In and Ga, and where at least one discrete layer comprising Cu is electrodeposited using a Cu electrolyte over another discrete layer comprising one of In and Ga; and (c) reacting the precursor stack with at least one of Se and S.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the solar cell.    sheet-shaped substrate (11)    an absorber layer (12)    conductive layer (13)    additional (transparent) layer (14)    radiation. (15)