NOVELTY - Fabrication of tandem photovoltaic cell (100) involves coupling the cell (101) with the cell (103). The formation of cell (101) involves forming absorber layer (a1) on the transparent conductive oxide layer (105), forming window layer (w1) on the layer (a1) and forming a transparent conductive oxide layer (115) on the layer (w1). The formation of cell (103) involves forming absorber layer (a2) on the electrode layer (e1), forming window layer (w2) on the layer (a2) and forming transparent conductive oxide layer (A) on the layer (w2) and forming a coupling layer on the layer (115).    USE - Fabrication of tandem photovoltaic cell used in electrical power application.    ADVANTAGE - The method enables economical fabrication of tandem photovoltaic cell with 10.4% conversion efficiency. The method eliminates the usage of thick window layer to protect the transparent conductive oxide layer from diffusion of material from the absorber layer. The electrode layer can be reflective to reflect electromagnetic radiation back to the photovoltaic cell, and improves the conversion efficiency of the photovoltaic cell.    DETAILED DESCRIPTION - Fabrication of tandem photovoltaic cell involves forming cell (101) and cell (103) and coupling the cell (101) with the cell (103). The formation of cell (101) involves forming transparent conductive oxide layer (105), forming absorber layer (a1) on the layer (105), forming window layer (w1) on the layer (a1) and forming a transparent conductive oxide layer (115) on the layer (w1). The layer (a1) comprises copper material, indium material and sulfur material. The formation of cell (103) involves forming electrode layer (e1), forming absorber layer (a2) on the layer (e1), forming window layer (w2) on the layer (a2) and forming transparent conductive oxide layer (A) on the layer (w2) and forming a coupling layer on the layer (115).    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of tandem photovoltaic cell.    Tandem photovoltaic cell (100)    Cells (101,103)    Transparent conductive oxide layers (105,115)    Transparent conductor layer (109)    Terminals (111,113,121,123)