Optoelectrical Modeling of Perovskite/Perovskite/Silicon Triple-Junction Solar Cells: Toward the Practical Efficiency Potential

Perovskite-based triple-junction solar cells offer the potential for highly efficient and cost-effective photovoltaic energy conversion. This article aims to provide a roadmap for the optical properties of perovskite/perovskite/silicon triple-junction cells. A comprehensive optoelectrical model for the perovskite/perovskite/silicon structure is developed in Sentaurus TCAD. The optical part of the model is validated by measurements of a triple-junction solar cell. As the electrical characterization is an ongoing process, the electrical properties are assumed to be nonlimiting, which enables us to translate the optical improvement steps into efficiency potentials. A first improvement step lies in adjusting the thicknesses of the perovskite layers to achieve current matching between both perovskite subcells. Using perovskites with bandgaps optimized for planar surfaces, it would be possible to increase the photocurrent density to 13.3 mA cm-2 and the efficiency to 41.9%. It is shown that by implementing a fully textured structure and using the best available materials, a short-circuit current of 14.1 mA cm-2 and an open-circuit voltage of 3.48 V with an efficiency of 44.3% are possible assuming idealized electrical properties. This can be regarded as a practical efficiency potential for this kind of triple-junction technology. This article aims to provide a roadmap to guide the development of the optical properties of perovskite/perovskite/silicon triple-junction cells. Thereby, simulations with Sentaurus TCAD are used, calculations with experimental data are validated, and selective measures to improve the power conversion efficiency are provided. The efficiency can be greatly improved by matching the current of the subcells, which can be achieved by the right combination of absorber thicknesses and perovskite bandgaps.image (c) 2024 WILEY-VCH GmbH