Year: 2008
Type: article
Abstract: Using synchrotron powder X-ray diffraction and small-angle X-ray scattering (SAXS), we have studied the structures of the two CdSe/ CdTe and CdTe/CdSe type II quantum dots (QDs), including the crystalline structure, particle shape and size, as well as phase separation of the two components.The X-ray results suggest that the spherical CdTe/CdSe QDs of a size of ~8 nm, synthesized in a twostep procedure with CdTe nanoparticles (4 nm) as nuclides, have a structure of a CdTe-rich core enclosed by a CdSe shell.On the other hand, the spherical CdSe/CdTe QDs of a size of ~9 nm, synthesized in a similar two-step procedure but with CdSe nanoparticles (~3 nm) as nuclides, show mainly one phase structure with a uniform distribution of CdSe and CdTe.The phase separation of the two components CdSe and CdTe inside the two QDs, a decisive factor in the photovoltaic applications, is furthermore examined using anomalous SAXS for a consistent conclusion.For comparison, single phase nanoparticles CdSe and CdTe are also examined.The correlation between the synthesis procedures and the structures of the QDs is discussed.
Authors: M.D. Eddleston, W. Jones
Institution: University of Cambridge
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2333044245