Heterojunctions and silicon/perovskite tandem solar cells
- Authors
- Publication Date
- Dec 13, 2021
- Source
- HAL-Descartes
- Keywords
- Language
- English
- License
- Unknown
- External links
Abstract
Perovskite (PVK) materials have been attracting a lot of attention in recent years for solar cell applications, notably because combining a top PVK subcell with a crystalline silicon (c-Si) bottom subcell in a tandem configuration is a promising way for overcoming the theoretical single-cell efficiency limit. Even though the performance of such devices has been well improved, the fundamental research of how this material system works is still lacking. While in practical solar cell devices, these two materials are normally not in direct contact, the knowledge of the carrier transport and band alignment at their interface would allow for a better understanding of their performance and compatibility. The aim of this thesis was to use a combined set of characterisation techniques to improve the understanding of the PVK/c-Si interface properties which can be used to develop strategies to reduce losses by minimising recombination of photogenerated carriers and improving their extraction in each sub-cell.By performing wavelength-dependent surface photovoltage measurements in Kelvin probe force microscopy configuration and analysing the surface and interface contributions to the signal measured at the top of the stack, we were able to determine whether the PVK/c-Si interface helps in carrier separation, or not, and to reveal long-term changes attributed to chemical-based processes. Complementary AC SPV measurements in a metal- insulator-semiconductor configuration and photoemission spectroscopy studies of the PVK/c- Si system allowed us to reconstruct the band alignment at the interface of these two materials. Our results serve as a foundation to study the compatibility of perovskite and c-Si, elucidating band alignment, charge transport and light induced photovoltage of this interface, and thus guiding the development of perovskite-silicon tandem solar cells in monolithic device architectures.
