Metal Oxides as Electron Selective Contacts

Various metal oxides such as Titanium Oxide (TiO₂), SnO₂, Zinc Oxide, Zinc Stannate (Zn₂SnO₄), SrTiO₃, and so forth have been used in perovskite solar cells which cater as electron transporting materials. Various nano-structures such as nanorods (NR), nanofibers (NF), and nanoplatelets of these metal oxides have been demonstrated in working perovskite solar cells. This chapter reviews the various metal oxides used in perovskite solar cells. M. Qin et al. employed a low-temperature solution processed method to deposit the indium oxide electron selective contact in perovskite solar cells. S. S. Kim et al. reported highly efficient perovskite solar cells based on TiO₂ rutile NRs grown through hydrothermal means. Immediate formation of perovskite due to strong ionic interactions between the metal cations and halogen anions hinders excellent infiltration of perovskite into the bottom of the TiO₂ scaffold. The NF-based perovskite cell has exceedingly high efficiency compared to the planar.