Electrical and Optical Investigation of 2T–Perovskite/u-CIGS Tandem Solar Cells With ~30% Efficiency

Abstract

In this article, the two-terminal perovskite/ u-CIGS tandem device is performed and investigated numerically using Atlas Silvaco-TCAD tools. The structural configuration of FTO/TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /MAPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Spiro-OMeTAD/Gold was performed, calibrated, and validated with overall good agreement. This validated numerical model is selected to be used as a top cell for the tandem device. In addition, the optimized ultrathin CIGS solar cell from our previous work has been used for a good substrate (bottom cell) for optimized perovskite top-cell. The simulated perovskite and u-CIGS cells have been performed individually revealing 17.84% and 12.41% efficiency, respectively, all in good agreement with published experimental results. The performed and calibrated tandem model is then studied to analyze the impact of changing the thickness of the cell layers such as for ETL, perovskite, HTL layers on perovskite, and tandem cell characteristics. The influence of the perovskite and HTL doping density is also investigated. The achieved results allow gaining a better understanding and a deeper insight into the effects of the physical dimensions and materials doping concentration on cell performance. After analyzing the optimal values from different changes, a new tandem cell configuration is proposed, which shows a good improvement in electrical characteristics with an efficiency of up to 30%.