Planar structures for halide perovskite solar cells have recently garnered attention, due to their simple and low-temperature device fabrication processing. Unfortunately, planar structures typically show I–V hysteresis and lower stable device efficiency compared with mesoporous structures, especially for TiO₂-based n-i-p devices. SnO₂, which has a deeper conduction band and higher electron mobility compared with traditional TiO₂, could enhance charge transfer from perovskite to electron transport layers, and reduce charge accumulation at the interface. Here we report low-temperature solution-processed SnO₂ nanoparticles as an efficient electron transport layer for perovskite solar cells. Our SnO₂-based devices are almost free of hysteresis, which we propose is due to the enhancement of electron extraction. By introducing a PbI₂ passivation phase in the perovskite layer, we obtain a 19.9 ± 0.6% certified efficiency. The devices can be easily processed under low temperature (150 ∘C), offering an efficient method for the large-scale production of perovskite solar cells.

Nature Energy 2, Article number: 16177 (2016)
doi:10.1038/nenergy.2016.177

http://www.nature.com/articles/nenergy2016177