Detailed Balance Calculation of a Novel Triple-Junction Solar Cell Structure

Abstract

In this paper, a novel triple-junction solar cell structure is investigated using a numerical simulation based on the detailed balance calculation. The topmost subcell is electrically connected in parallel to other two subcells, while the latter are connected in series in the new triple-junction solar cell structure. The theoretical limiting efficiencies under AM1.5G, AM1.5D, and AM0 illumination conditions are calculated to be 50.5%, 49.8%, and 46.6%, respectively, at 300 K. This study shows that the top subcell's bandgap for this new structure possesses a wide optimum energy range. It presents diverse electrical behaviors and different optimum bandgap combinations from those of an in-series connected triple-junction solar cell. Here, we present its schematic structure, as well as the optimum bandgap combinations and current density-voltage characteristics. The results suggest that the new triple-junction solar cell structure is feasible and competitive as it shows a wide optimum bandgap energy range for the top subcell with high limiting efficiency of the solar cell.