title: Theoretical performance of multi-junction solar cells combining III-V and Si materials.
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.
authors.affiliation: Tyndall National Institute, UCC, Lee Maltings, Prospect Row, Cork, Ireland. ian.mathews@tyndall.ie
authors.forename: Ian
authors.initials: I
authors.lastname: Mathews
authors.forename: Donagh
authors.initials: D
authors.lastname: O'Mahony
authors.forename: Brian
authors.initials: B
authors.lastname: Corbett
authors.forename: Alan P
authors.initials: AP
authors.lastname: Morrison