A Multijunction Solar Cell Simulation Program for the Development of Concentration Systems

The first version of a solar cell simulator specifically designed for the analysis of multijunction solar cells is presented. The simulation program solves the Poisson and continuity equations by using a procedure optimized for multilayer structures. It includes the radiative interband, Shockley-Read-Hall and Auger recombination mechanisms, and computes the generation function of electron-hole pairs from the optical parameters of the cell materials. The dependence of these optical parameters with the photon energy has been included, taking into account the doping level and its effect on bandgap narrowing. The simulator is applied to the analysis of a dual-junction GalnP/GaAs solar cell, obtaining results comparable to experimental data reported by different authors. More advanced versions of the simulator are in progress, with the aim of obtaining a tool useful for optimal design of multijunction solar cells.