Different approaches have been made in order to reach higher efficiencies. Concepts for multilayer solar cells have been developed. This can be realised if multiple individual single junction solar cells with different, suitably chosen band gaps are connected in series in multi-junction solar cells. In our work, we have simulated and optimized solar cells based on the system mechanically stacked using computer modelling and predict their maximum performance. The structures of solar cells are based on the single junction Si, Ge and GaAs cells. We have simulated each cell individually and extracted their optimal parameters (thickness, concentration, the recombination velocity…..), also, we calculated the efficiency of each cells optimized by separation of the solar spectrum in bands where the cell is sensible for the absorption. The optimal values of physical parameters giving the best current of short-circuit and voltages of open circuit as well high conversion efficiency have obtained for the two solar materials and tandem.Different approaches have been made in order to reach higher efficiencies. Concepts for multilayer solar cells have been developed. This can be realised if multiple individual single junction solar cells with different, suitably chosen band gaps are connected in series in multi-junction solar cells. In our work, we have simulated and optimized solar cells based on the system mechanically stacked using computer modelling and predict their maximum performance. The structures of solar cells are based on the single junction Si, Ge and GaAs cells. We have simulated each cell individually and extracted their optimal parameters (thickness, concentration, the recombination velocity…..), also, we calculated the efficiency of each cells optimized by separation of the solar spectrum in bands where the cell is sensible for the absorption. The optimal values of physical parameters giving the best current of short-circuit and voltages of open circuit as well high conversion efficiency have obtained for the two solar materials and tandem
