title: Ultrafast Carrier Dynamics and Hot Electron Extraction in Tetrapod-Shaped CdSe Nanocrystals.
abstract: The ultrafast carrier dynamics and hot electron extraction in tetrapod-shaped CdSe nanocrystals was studied by femtosecond transient absorption (TA) spectroscopy. The carriers relaxation process from the higher electronic states (CB2, CB3(2), and CB4) to the lowest electronic state (CB1) was demonstrated to have a time constant of 1.04 ps, resulting from the spatial electron transfer from arms to a core. The lowest electronic state in the central core exhibited a long decay time of 5.07 ns in agreement with the reported theoretical calculation. The state filling mechanism and Coulomb blockade effect in the CdSe tetrapod were clearly observed in the pump-fluence-dependent transient absorption spectra. Hot electrons were transferred from arm states into the electron acceptor molecules before relaxation into core states.
authors.affiliation: †State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors.forename: Pengtao
authors.initials: P
authors.lastname: Jing
authors.affiliation: †State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors.forename: Wenyu
authors.initials: W
authors.lastname: Ji
authors.affiliation: ‡Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Yuan
authors.affiliation: †State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China.
authors.forename: Songnan
authors.initials: S
authors.lastname: Qu
authors.affiliation: §College of Chemistry, Jilin University, Changchun 130012, China.
authors.forename: Renguo
authors.initials: R
authors.lastname: Xie
authors.affiliation: ∥Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Ikezawa
authors.affiliation: ‡Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, China.
authors.forename: Jialong
authors.initials: J
authors.lastname: Zhao
authors.affiliation: ‡Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Li
authors.affiliation: ∥Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Masumoto
keywords: carrier dynamics; electron transfer; nanocrystals; tetrapod; transient absorption spectroscopy