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Doping Induced Orbit–Orbit Interaction between Excitons While Enhancing Photovoltaic Performance in Tin Perovskite Solar Cells
journal contribution
posted on 2020-08-12, 21:19 authored by Jia Zhang, Jiajun Qin, Ting Wu, Bin HuDoping has been used
as a common method to improve photovoltaic
performance in perovskite solar cells (PSCs). This paper reports a
new phenomenon that the SnF2 doping can largely increase
the exciton–exciton interaction through orbital magnetic dipoles
toward increasing dissociation probabilities in lead-free FASnI2Br PSCs. Essentially, when orbit–orbit interaction
between excitons occurs, linearly and circularly polarized photoexcitations
can inevitably generate different photocurrents, giving rise to a
ΔJsc phenomenon. Here, it is found
that, when SnF2 doping is used to boost photovoltaic efficiency
to 7.61%, the orbit–orbit interaction is increased by a factor
of 2.2, shown as the ΔJsc changed
from 1.21% to 0.55%. Simultaneously, magnetic field effects of Jsc indicate that increasing orbit–orbit
interaction leads to an increase on the spin–orbital coupling
in Sn perovskites (FASnI2Br) upon SnF2 doping.
This presents a new doping effect occurring in the Sn perovskite solar
cell toward enhancing photovoltaic efficiency.