title: Tailoring the Interfacial Chemical Interaction for High-Efficiency Perovskite Solar Cells.
abstract: The ionic nature of perovskite photovoltaic materials makes it easy to form various chemical interactions with different functional groups. Here, we demonstrate that interfacial chemical interactions are a critical factor in determining the optoelectronic properties of perovskite solar cells. By depositing different self-assembled monolayers (SAMs), we introduce different functional groups onto the SnO2surface to form various chemical interactions with the perovskite layer. It is observed that the perovskite solar cell device performance shows an opposite trend to that of the energy level alignment theory, which shows that chemical interactions are the predominant factor governing the interfacial optoelectronic properties. Further analysis verifies that proper interfacial interactions can significantly reduce trap state density and facilitate the interfacial charge transfer. Through use of the 4-pyridinecarboxylic acid SAM, the resulting perovskite solar cell exhibits striking improvements to the reach the highest efficiency of 18.8%, which constitutes an ∼10% enhancement compared to those without SAMs. Our work highlights the importance of chemical interactions at perovskite/electrode interfaces and paves the way for further optimizing performances of perovskite solar cells.
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Lijian
authors.initials: L
authors.lastname: Zuo
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Nicholas
authors.initials: N
authors.lastname: De Marco
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Yao-Tsung
authors.initials: YT
authors.lastname: Hsieh
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Huajun
authors.identifier: 0000-0003-1150-2623
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Pengyu
authors.initials: P
authors.lastname: Sun
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Sheng-Yung
authors.initials: SY
authors.lastname: Chang
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Hongxiang
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Shiqi
authors.initials: S
authors.lastname: Dong
authors.affiliation: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors.forename: Yang
authors.identifier: 0000-0001-8833-7641
authors.initials: Y
authors.lastname: Yang
keywords: Perovskite solar cells; coordination bond; energy level alignment; interfacial chemical interactions; self-assembly monolayer; trap states passivation