Charge transport layers strongly influence the performance of perovskite solar cells (PSCs). To date, compact layers and mesoporous scaffolds of titanium dioxide have emerged as good electron transport layers (ETL), enabling record power conversion efficiencies (PCE). However, these ETLs require sintering above 400 °C, which excludes them from low-temperature applications such as flexible devices and silicon-heterojunction tandems. Furthermore, instability of TiO2 under prolonged exposure to sunlight appears to be a critical issue. Here, we present the promising characteristics of low-temperature processed strontium titanate (STO) as an ETL to realize PSCs with 19% PCE. STO is a wide bandgap transparent inorganic perovskite. Compared with other low-temperature processed interlayers, STO reduces the parasitic absorption in the ultraviolet and visible range, improves the electron transport, and greatly increases the stability of the devices, retaining ∼80% of their initial efficiency after 1000 h of constant white light illumination.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). Authors would like to acknowledge financial support from EC FP7 Project SC2 (610115) and EPSRC Projects EP/G037515/1 and EP/M005143/1. This work was also supported by computational time granted from the Greek Research & Technology Network (GRNET) in the National HPC facility − ARIS − under project pr004034- STEM. The authors acknowledge Dr. Muhammed Sajjad and Dr. Ahmed Mansour for the useful discussion regarding the STO structure.