title: Enhanced electronic properties in mesoporous TiO2 via lithium doping for high-efficiency perovskite solar cells.
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 TiO2 is accomplished by facile post treatment of the films with lithium salts. We demonstrate that the Li-doped TiO2 electrodes 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 CH3NH3PbI3 light 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%).
authors.affiliation: Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Giordano
authors.affiliation: Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Antonio
authors.initials: A
authors.lastname: Abate
authors.affiliation: Laboratoire des sciences photomoléculaires, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Correa Baena
authors.affiliation: Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Saliba
authors.affiliation: Advanced Research Division, Materials Research Laboratory, Panasonic Corporation, 1006, Kadoma, Kadoma City, Osaka 571-8501, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Department of Chemical Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Sang Hyuk
authors.initials: SH
authors.lastname: Im
authors.affiliation: Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Shaik M
authors.initials: SM
authors.lastname: Zakeeruddin
authors.affiliation: Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Mohammad Khaja
authors.initials: MK
authors.lastname: Nazeeruddin
authors.affiliation: Laboratoire des sciences photomoléculaires, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Anders
authors.initials: A
authors.lastname: Hagfeldt
authors.affiliation: Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Graetzel