title: Microstructural and optical properties of CdSe/CdS/ZnS core-shell-shell quantum dots.
abstract: CdSe/CdS/ZnS core-shell-shell quantum dots (QDs) were synthesized by using a solution process. High-resolution transmission electron microscopy images and energy dispersive spectroscopy profiles confirmed that stoichiometric CdSe/CdS/ZnS core-shell-shell QDs were formed. Ultraviolet-visible absorption and photoluminescence (PL) spectra of CdSe/CdS/ZnS core-shell-shell QDs showed the dominant excitonic transitions from the ground electronic subband to the ground hole subband (1S(e)-1S(3/2)(h)). The PL mechanism is suggested; the carriers generated by the exciting high-energy photons in the shell region are relaxed to the band-edge states of the core region and recombined to emit lower-energy photons. The activation energy of the carriers confined in the CdSe/CdS/ZnS core-shell-shell QDs, as obtained from temperature-dependent PL spectra, was 200 meV. The quantum efficiency of the CdSe/CdS/ZnS core-shell-shell QDs at 300 K was estimated to be approximately 57%.
authors.forename: Dea Uk
authors.initials: DU
authors.lastname: Lee
authors.forename: Dae Hun
authors.initials: DH
authors.lastname: Kim
authors.forename: Dong Hyuk
authors.initials: DH
authors.lastname: Choi
authors.forename: Sang Wook
authors.initials: SW
authors.lastname: Kim
authors.forename: Hong Seok
authors.initials: HS
authors.lastname: Lee
authors.forename: Keon-Ho
authors.initials: KH
authors.lastname: Yoo
authors.forename: Tae Whan
authors.initials: TW
authors.lastname: Kim