title: Upconversion luminescence of CdTe nanocrystals by use of near-infrared femtosecond laser excitation.
abstract: We study the steady-state and time-resolved luminescent properties of CdTe nanocrystals by one- and two-photon excitation with a femtosecond laser. We observe that 1208 nm excitation causes a shift of the emission peak of about 20 nm to the infrared compared with 400 nm laser excitation. It is found that upconversion luminescence is composed of a photoinduced trapping and a band edge excitonic state and produces the observation of biexponential decay kinetics. We conclude that the redshift of the emission peak is caused by the relative change in luminescence intensity between excitonic and trapping states.
authors.affiliation: Center for Condensed Matter Science and Technology, Harbin Institute of Technology, China.
authors.forename: W Z
authors.initials: WZ
authors.lastname: Wu
authors.forename: Z R
authors.initials: ZR
authors.lastname: Zheng
authors.forename: W L
authors.initials: WL
authors.lastname: Liu
authors.forename: J P
authors.initials: JP
authors.lastname: Zhang
authors.forename: Y X
authors.initials: YX
authors.lastname: Yan
authors.forename: Q H
authors.initials: QH
authors.lastname: Jin
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Yang
authors.forename: W H
authors.initials: WH
authors.lastname: Su