Spectroscopy and femtosecond dynamics of type-II CdTe/CdSe core-shell quantum dots.
Syntheses of CdTe/CdSe type-II quantum dots (QDs) using CdO and CdCl2 as precursors for core and shell, respectively, are reported. Characterization was made via near-IR interband emission, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDX), and X-ray diffraction (XRD). Femtosecond fluorescence upconversion measurements on the relaxation dynamics of the CdTe core (in CdTe/CdSe) emission and CdTe/CdSe interband emission reveal that as the size of the core increases from 5.3, 6.1 to 6.9 nm, the rate of photoinduced electron separation decreases from 1.96, 1.44 to 1.07 x10(12) s(-1). The finite rates of the initial charge separation are tentatively rationalized by the small electron-phonon coupling, causing weak coupling between the initial and charge-separated states.
Chou
Pi-Tai
PT
Department of Chemistry, National Taiwan University, Taipei 106, Taiwan. chop@ntu.edu.tw
Chen
Chun-Yen
CY
Cheng
Chiu-Ting
CT
Pu
Shih-Chieh
SC
Wu
Kun-Chan
KC
Cheng
Yi-Ming
YM
Lai
Chih-Wei
CW
Chou
Yi-Hsuan
YH
Chiu
Hsin-Tien
HT