title: Carrier Diffusion Lengths of over 500 nm in Lead-Free Perovskite CH3NH3SnI3Films.
abstract: The dynamics of photoexcited lead-free perovskite films, CH3NH3SnI3, were studied using broadband transient absorption and time-resolved fluorescence spectroscopy. Similar to its lead analogue CH3NH3PbI3, we show that free carrier (electrons and holes) recombination is also the dominant relaxation pathway in CH3NH3SnI3films. The slow hot carrier relaxation time is 0.5 ps. Long carrier diffusion lengths for electrons (279 ± 88 nm) and holes (193 ± 46 nm) were obtained from fluorescence quenching measurements. We also show that SnF2doping in the CH3NH3SnI3film effectively increases the fluorescence lifetime up to 10 times and gives diffusion lengths exceeding 500 nm. These results suggest that the photophysics of CH3NH3SnI3perovskite are as favorable as those of CH3NH3PbI3, demonstrating that it is a promising nontoxic lead-free replacement for lead iodide perovskite-based solar cells.
authors.affiliation: Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern (ISEN), Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Lin
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern (ISEN), Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Feng
authors.initials: F
authors.lastname: Hao
authors.affiliation: Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern (ISEN), Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Constantinos C
authors.initials: CC
authors.lastname: Stoumpos
authors.affiliation: Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern (ISEN), Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Phelan
authors.affiliation: Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern (ISEN), Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Wasielewski
authors.affiliation: Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern (ISEN), Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis