title: Cauliflower-like CdS microspheres composed of nanocrystals and their physicochemical properties.
abstract: Cauliflower-like cadmium sulfide (CdS) microspheres composed of nanocrystals have been successfully synthesized by a hydrothermal method using poly(ethylene glycol) (PEG) as the template coordination agent and characterized by a variety of methods. Our experiments confirmed that the size of the CdS microspheres could be easily modified by controlling the chain length of PEG. Powder X-ray diffraction and Raman spectroscopy measurements revealed the cubic structure of the CdS microspheres; morphological studies performed by HR-SEM and HR-TEM methods showed the cauliflower-like structure of the synthesized CdS microspheres. Each microsphere was identified to be created by the self-assembly of CdS nanocrystals and is attributed to the oriented aggregation of the CdS nanocrystals around a polymer-Cd(2+) complex spherical framework structure. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray (EDX) analysis confirmed the stoichiometries of the CdS microspheres. Diffuse reflectance spectrum (DRS) measurements showed that increasing the PEG chain length increased the band gap value of the CdS microspheres slightly, from 1.99 to 2.06 eV. The cauliflower-like CdS microspheres could be applied to photocatalytic degradation studies.
authors.affiliation: University of Eastern Finland, Laboratory of Applied Environmental Chemistry, Patteristonkatu 1, FI-50100 Mikkeli, Finland. srengaraj1971@yahoo.com
authors.forename: Selvaraj
authors.initials: S
authors.lastname: Rengaraj
authors.forename: Selvaraj
authors.initials: S
authors.lastname: Venkataraj
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Jee
authors.forename: Younghun
authors.initials: Y
authors.lastname: Kim
authors.forename: Cheuk-wai
authors.initials: CW
authors.lastname: Tai
authors.forename: Eveliina
authors.initials: E
authors.lastname: Repo
authors.forename: Arto
authors.initials: A
authors.lastname: Koistinen
authors.forename: Adriana
authors.initials: A
authors.lastname: Ferancova
authors.forename: Mika
authors.initials: M
authors.lastname: Sillanpää