Numerical simulations of novel SiGe-based IBC-HJ solar cell for standalone and mechanically stacked tandem applications

Abstract In this study, a novel 10 μm thick interdigitated back contact silicon-germanium heterojunction (IBC-Si 1- x Ge x HJ) solar cell device has been designed and simulated for standalone and four-terminal mechanically stacked tandem applications. Optimization of i-a-SiGe: H thickness, the width of n-a-SiGe: H region, p-a-SiGe: H region and gap along with composition fraction ( x ) lead to 15.5% power conversion efficiency (PCE) in a stand-alone configuration. Whereas in combination with perovskite top subcell we further demonstrate 25.7% PCE in four-terminal tandem configuration. In mechanical stacking, top and bottom subcells are fabricated individually and then assembled in a module, which avoids the need for current matching between subcells, thereby giving greater process and design flexibility. The proposed IBC-SiGeHJ solar cell is ∼ (25–30) times thinner than conventional Si solar cells which are used as bottom subcell in perovskite/silicon tandem solar cell. The results reveal that the proposed 4-terminal mechanically stacked perovskite/IBC-SiGeHJ tandem device may open new doors for the energy efficient applications. All the simulations have been done using Silvaco technology computer aided design (TCAD) simulator.