title: Interfacial Charge-Carrier Trapping in CH3NH3PbI3-Based Heterolayered Structures Revealed by Time-Resolved Photoluminescence Spectroscopy.
abstract: The fast-decaying component of photoluminescence (PL) under very weak pulse photoexcitation is dominated by the rapid relaxation of the photoexcited carriers into a small number of carrier-trapping defect states. Here, we report the subnanosecond decay of the PL under excitation weaker than 1 nJ/cm(2) both in CH3NH3PbI3-based heterostructures and bare thin films. The trap-site density at the interface was evaluated on the basis of the fluence-dependent PL decay profiles. It was found that high-density defects determining the PL decay dynamics are formed near the interface between CH3NH3PbI3 and the hole-transporting Spiro-OMeTAD but not at the CH3NH3PbI3/TiO2 interface and the interior regions of CH3NH3PbI3 films. This finding can aid the fabrication of high-quality heterointerfaces, which are required improving the photoconversion efficiency of perovskite-based solar cells.
authors.affiliation: Department of Physics, Chiba University , Inage-ku, Chiba 263-8522, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Shimazaki
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Wakamiya
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kanemitsu