Heterocyclic halides as passivating layer improves photovoltaic properties and intrinsic stability in perovskite solar cells*

Perovskites solar cells have irrupted in the photovoltaic field with no precedent. Rising from ~4% to 23.2% the power conversion efficiencies (PCE), however long term stability together with the lack of a fully understanding of intrinsic processes are still issues which need to be undertaken. To improve the intriguing challenges, compositional engineering of perovskites as well as molecular engineering of hole transport materials (HTMs) were adopted. Furthermore, an optimized interface between the different layers of the perovskite device is paramount to improve the problems aforementioned. In this regard, an optimized surface passivation layer is seen as an ideal approach to protect the surface from extrinsic factors, without altering the electro-optical properties.
In this work, we present the utilization of a passivation layer, which protect the perovskite layer from atmospheric attack. An improved PCE (20%) was also obtained compare with reference devices (18%), as the passivation layer will restricts the flow of electron towards the HTM layers and reduce recombination processes.
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