ISSN:
1573-4846
Schlagwort(e):
CdSe nanocrystals
;
silica xerogels
;
sonogels
;
SAXS
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract Small-angle X-ray scattering (SAXS) experiments were carried out to characterize the structure of the composite formed by CdSe nanocrystals embedded in a popous silica matrix (silica xerogels containing Cd with formamide addition and ultrasound treatment). SAXS results from samples before Se diffusion indicate the presence of heterogeneities with a bimodal size distribution which was associated to the existence of mesopores (pores of several hundred Å) immersed in a nanoporous matrix (characteristic pore radii of 20–30 Å). The diffusion of Se induces the nucleation and growth of CdSe nanocrystals. The average size of the nanocrystals increases with Cd content. Higher Se doses promote the formation of larger nanocrystals (radius of gyration of ∼30 to 50 Å). Anomalous scattering results confirm the existence of Se aggregation associated with CdSe nanocrystal formation and suggest that only partial segregation of Cd and Se occurs.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02436853
Permalink
