title: Anomalous photovoltaic effect in organic-inorganic hybrid perovskite solar cells.
abstract: Organic-inorganic hybrid perovskites (OIHPs) have been demonstrated to be highly successful photovoltaic materials yielding very-high-efficiency solar cells. We report the room temperature observation of an anomalous photovoltaic (APV) effect in lateral structure OIHP devices manifested by the device's open-circuit voltage (VOC) that is much larger than the bandgap of OIHPs. The persistentVOCis proportional to the electrode spacing, resembling that of ferroelectric photovoltaic devices. However, the APV effect in OIHP devices is not caused by ferroelectricity. The APV effect can be explained by the formation of tunneling junctions randomly dispersed in the polycrystalline films, which allows the accumulation of photovoltage at a macroscopic level. The formation of internal tunneling junctions as a result of ion migration is visualized with Kelvin probe force microscopy scanning. This observation points out a new avenue for the formation of large and continuously tunableVOCwithout being limited by the materials' bandgap.
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656, USA.; Hunan Key Laboratory of Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China.
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588-0299, USA.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Xing
authors.affiliation: Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588-0299, USA.
authors.forename: Alexei
authors.initials: A
authors.lastname: Gruverman
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656, USA.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Huang
keywords: Anomalous Photovoltaic Effect; Organic-Inorganic Hybrid Perovskite; perovskite; solar cells