Simulation of multijunction solar cell interfaces for enhancement of the power conversion efficiency

The problems with traditional solar cells are mainly their high cost and low conversion efficiency, which severely restricts the advancement of these cells in real-world uses. Therefore, in order to maximise the efficiency of GaAs/AlGaAs thin-film heterostructures, GaAs/AlGaAs solar cells were numerically simulated along with Mo(S,Se)2 and CH3NH3PbI3 layers in order to determine the most suitable candidate for maximising its power conversion efficiency. Both two dimensional (2D) and three dimensional (3D) solar cells were simulated using COMSOL Multiphysics and it was found that the structure which had the highest efficiency was Mo(S,Se)2/GaAs/AlGaAs. The lowering of the Schottky barrier at the semiconductor-metal electrode interface and the low recombination rates reported in the Mo(S,Se)2 layer may have contributed to its high efficiency rates. The combined effect resulted in a open circuit voltage (VOC) of 0.61 V, short circuit current density (JSC) of 43.65 mA/cm2, fill factor (FF) of 76.6% and power conversion efficiency (PCE) of 20.53%. In addition, the optimum thickness for the Mo(S,Se)2 and the CH3NH3PbI3 layers was found to be 40 and 600 nm, respectively. These results allow for the promotion of highly efficient GaAs/AlGaAs heterostructures and provide an effective strategy and source for the manufacture of high-performance thin-film solar cells. For the first time Mo(S,Se)2, CH3NH3PbI3 or a combination of both were numerically simulated with a GaAs/AlGaAs solar cell using the software COMSOL Multiphysics. It was found that the addition of the Mo(S,Se)2 layer to GaAs/AlGaAs had the greatest effect resulting in a PCE of 20.53% indicating that it is a suitable addition to such solar cells. For the first time the best thicknesses of the Mo(S,Se)2 and CH3NH3PbI3 layers were studied for the highest efficiency and found to be 40 and 600 nm respectively.