Spontaneous decoration of ionic compound at the perovskite interfaces to
achieve 23.38% efficiency with 85% fill factor in NiOX-based
perovskite solar cells
Abstract
Inorganic hole transporting materials (HTMs), particularly NiOX, have
shown significant promise in boosting the efficiency and stability of
perovskite solar cells. However, a major challenge facing NiOX-based
p-i-n perovskite solar cells (PSCs) is their direct contact with the
absorber layer, which can lead to photovoltage and filling factor
losses. Additionally, under-coordinated Ni cations can react with the
perovskite and cause damage. In this work, we address these issues by
using an ionic compound (QAPyBF4) as a perovskite additive to passivate
the entire perovskite layer and interact with under-coordinated Ni
cations. Our results show that the introduction of QAPyBF4 significantly
enhances the performance and stability of NiOX-based PSCs. Specifically,
the decorated cells achieved a power conversion efficiency (PCE) of
23.38% and a fill factor (FF) of 85.46%, with no need for complicated
surface treatment or NiOX doping. The QAPyBF4 compound passivates the
buried NiOX/perovskite interface, effectively reducing photovoltage and
filling factor losses. Moreover, the [BF4]‒ component of the
compound interacts with under-coordinated Ni cations to prevent their
negative impact on the perovskite layer. Overall, our study proposes a
simple and effective approach to optimize the performance and stability
of NiOX-based PSCs through the use of ionic compound additives. Our
findings suggest that addressing buried NiOX/perovskite interface issues
and under-coordinated Ni cation considerations are critical in achieving
high-performance and stable NiOX-based PSCs.