title: The nature of free-carrier transport in organometal halide perovskites.
abstract: Organometal halide perovskites are attracting great attention as promising material for solar cells because of their high power conversion efficiency. The high performance has been attributed to the existence of free charge carriers and their large diffusion lengths, but the nature of carrier transport at the atomistic level remains elusive. Here, nonadiabatic quantum molecular dynamics simulations elucidate the mechanisms underlying the excellent free-carrier transport in CH3NH3PbI3. Pb and I sublattices act as disjunct pathways for rapid and balanced transport of photoexcited electrons and holes, respectively, while minimizing efficiency-degrading charge recombination. On the other hand, CH3NH3 sublattice quickly screens out electrostatic electron-hole attraction to generate free carriers within 1 ps. Together this nano-architecture lets photoexcited electrons and holes dissociate instantaneously and travel far away to be harvested before dissipated as heat. This work provides much needed structure-property relationships and time-resolved information that potentially lead to rational design of efficient solar cells.
authors.affiliation: Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Hakamata
authors.affiliation: Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan.|Collaboratory for Advanced Computing and Simulations, Department of Physics &Astronomy, Department of Computer Science, Department of Chemical Engineering &Materials Science, and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0242, USA.|Graduate School of System Informatics, Kobe University, Kobe 657-8501, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Shimamura
authors.affiliation: Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan.
authors.forename: Fuyuki
authors.initials: F
authors.lastname: Shimojo
authors.affiliation: Collaboratory for Advanced Computing and Simulations, Department of Physics &Astronomy, Department of Computer Science, Department of Chemical Engineering &Materials Science, and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0242, USA.
authors.forename: Rajiv K
authors.initials: RK
authors.lastname: Kalia
authors.affiliation: Collaboratory for Advanced Computing and Simulations, Department of Physics &Astronomy, Department of Computer Science, Department of Chemical Engineering &Materials Science, and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0242, USA.
authors.forename: Aiichiro
authors.initials: A
authors.lastname: Nakano
authors.affiliation: Collaboratory for Advanced Computing and Simulations, Department of Physics &Astronomy, Department of Computer Science, Department of Chemical Engineering &Materials Science, and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0242, USA.
authors.forename: Priya
authors.initials: P
authors.lastname: Vashishta