Self-assembled interlayer aiming at the stability of NiOx based perovskite solar cells

Inorganic NiOx based inverted structure perovskite solar cells (PSCs) is reported to be more stable than that with the organic hole transport materials. In this work, NiOx/MAPbI(3) interface chemical reaction induced instability of perovskite is unveiled: Ni3+ and I exhibit redox reactions and deprotonation of MA(+) happens, which result in interface defects and perovskite lattice deformation. Thus the defective interface accelerates the degradation of perovskite by defect pathways from the bottom interface to the perovskite surface contacting H2O/O-2. Self-assembled interlayer of NH2 end silane on NiOx separates the reactive NiOx and MAPbI(3), tunes the interface energy states by -NH2 end group. As a result, the PSC based on the silane treated NiOx achieves enhanced PCE of 20.1% with decent stability under environmental and extreme conditions (high temperature, high humidity, light infiltration). Our work highlights the interface chemical problem induced PSC instability and a simple interface modification to achieve the stable PSCs. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

This study reveals the instability issue of perovskite in inorganic NiOx-based inverted structure perovskite solar cells (PSCs) caused by the interface chemical reactions between NiOx and MAPbI(3), and proposes a simple interface modification method using a self-assembled interlayer of silane to achieve stable PSCs with enhanced performance.