title: Dynamics of Charged Excitons and Biexcitons in CsPbBr3Perovskite Nanocrystals Revealed by Femtosecond Transient-Absorption and Single-Dot Luminescence Spectroscopy.
abstract: Metal-halide perovskite nanocrystals (NCs) are promising photonic materials for use in solar cells, light-emitting diodes, and lasers. The optoelectronic properties of these devices are determined by the excitons and exciton complexes confined in their NCs. In this study, we determined the relaxation dynamics of charged excitons and biexcitons in CsPbBr3NCs using femtosecond transient-absorption (TA), time-resolved photoluminescence (PL), and single-dot second-order photon correlation spectroscopy. Decay times of ∼40 and ∼200 ps were obtained from the TA and PL decay curves for biexcitons and charged excitons, respectively, in NCs with an average edge length of 7.7 nm. The existence of charged excitons even under weak photoexcitation was confirmed by the second-order photon correlation measurements. We found that charged excitons play a dominant role in luminescence processes of CsPbBr3NCs. Combining different spectroscopic techniques enabled us to clarify the dynamical behaviors of excitons, charged excitons, and biexcitons.
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Yarita
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tahara
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ihara
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Tokuhisa
authors.initials: T
authors.lastname: Kawawaki
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Sato
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Saruyama
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Teranishi
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Yoshihiko
authors.identifier: http://orcid.org/0000-0002-0788-131X
authors.initials: Y
authors.lastname: Kanemitsu