Theoretical performance of multi-junction solar cells combining III-V and Si materials Ian Mathews,1,2* Donagh O'Mahony,1 Brian Corbett1 and Alan P. Morrison1,2 1Tyndall National Institute, UCC, Lee Maltings, Prospect Row, Cork, Ireland 2Department of Electrical and Electronic Engineering, University College Cork, Cork, Ireland *
[email protected] Abstract: A route to improving the overall efficiency of multi-junction solar cells employing conventional III-V and Si photovoltaic junctions is presented here. A simulation model was developed to consider the performance of several multi-junction solar cell structures in various multi- terminal configurations. For series connected, 2-terminal triple-junction solar cells, incorporating an AlGaAs top junction, a GaAs middle junction and either a Si or InGaAs bottom junction, it was found that the configuration with a Si bottom junction yielded a marginally higher one sun efficiency of 41.5% versus 41.3% for an InGaAs bottom junction. A significant efficiency gain of 1.8% over the two-terminal device can be achieved by providing an additional terminal to the Si bottom junction in a 3-junction mechanically stacked configuration. It is shown that the optimum performance can be achieved by employing a four-junction series-connected mechanically stacked device incorporating a Si subcell between top AlGaAs/GaAs and bottom In0.53Ga0.47As cells. © 2012 Optical Society of America OCIS Codes: (230.0230) Optical devices; (350.6050) Solar energy; (040.5350) Photovoltaic. References and links 1. M. A. Green, K. Emery, Y. Hishikawa, W. Warta, and E. D. Dunlop, “Solar cell efficiency tables (version 39),” Prog.