posted on 2021-05-17, 17:33authored byArup Mahata, Daniele Meggiolaro, Luca Gregori, Filippo De Angelis
Tin
is a valuable candidate for replacing lead in perovskites solar
cells. Tin oxidation, however, strongly limits the efficiency and
the long-term stability of tin halide perovskites (THP) in devices.
To mitigate this issue, capping 3D THP with analogue 2D perovskites
through the addition of large cations is an emerging strategy, leading
to increased performance and stability. In this study, based on the
state of the art density functional theory calculations, the possible
beneficial effects of large cations (BA, PEA, and AVA) on the tin
stability at the surface is investigated. Our results show that large
cation dipoles of the 2D perovskites modulate tin oxidation potential
at the surface of 3D perovskites by hindering the formation of tin
vacancies and the degradation of the material. This study confirms
that stabilization of tin at the surface is key for the full exploitation
of THP in long-term stable devices.