PUB - Publikationen an der Universität Bielefeld

**Abstract**
Perovskite solar cells are one of the most promising photovoltaic technologies with their extraordinary progress in efficiency and the simple processes required to produce them. However, the frequent presence of a pronounced hysteresis in the current voltage characteristic of these devices arises concerns on the intrinsic stability of organo-metal halides, challenging the reliability of technology itself. Here, we show that n-doping of mesoporous TiO₂is accomplished by facile post treatment of the films with lithium salts. We demonstrate that the Li-doped TiO₂electrodes exhibit superior electronic properties, by reducing electronic trap states enabling faster electron transport. Perovskite solar cells prepared using the Li-doped films as scaffold to host the CH₃NH₃PbI₃light harvester produce substantially higher performances compared with undoped electrodes, improving the power conversion efficiency from 17 to over 19% with negligible hysteretic behaviour (lower than 0.3%).