Colloidal Anisotropic ZnO鈥揊e@FexOy Nanoarchitectures with Interface-Mediated Exchange-Bias and Band-Edge Ultraviolet Fluorescence

详细信息    查看全文

• 作者：Athanasia Kostopoulou ; Franck Th茅tiot ; Ioannis Tsiaoussis ; Maria Androulidaki ; P. Davide Cozzoli ; Alexandros Lappas
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：July 24, 2012
• 年：2012
• 卷：24
• 期：14
• 页码：2722-2732
• 全文大小：534K
• 年卷期：v.24,no.14(July 24, 2012)
• ISSN：1520-5002

文摘

Hybrid nanocrystals (HNCs), based on ZnO nanorods (NRs) decorated with magnetic Fe-based domains, were synthesized via a colloidal seeded-growth method. The approach involved heterogeneous nucleation of Fe nanocrystals on size-tailored ZnO nanorod seeds in a noncoordinating solvent, followed by partial surface oxidation of the former to the corresponding Fe@Fe_xO_y core@shell domains. HNCs with variable population and size of the Fe-based nanodomains could be synthesized depending on the surface reactivity of the ZnO seeds. The structure鈥損roperty relationships in these HNCs were carefully studied. In HNCs characterized by a large number of small Fe@Fe_xO_y core@shell nanodomains on the ZnO seed surface, the interfacial communication across the Fe-core and Fe_xO_y-shell generated a sizable exchange-bias effect mediated by frozen interfacial spins. On the other hand, in HNCs carrying a lower density of comparatively larger Fe@Fe_xO_y domains, partial removal of the Fe-core created an inner void in between that led to suppressed exchange coupling anisotropy. As a further proof of functionality, the HNCs exhibited pronounced band-edge ultraviolet fluorescence. The latter was blue-shifted compared to the parent ZnO NRs, inferring coupling of the semiconductor and magnet sections.

Keywords:

p://pubs.acs.org/action/doSearch?action=search&searchText=hybrid+nanocrystals&qsSearchArea=searchText">hybrid nanocrystals; p://pubs.acs.org/action/doSearch?action=search&searchText=colloidal+synthesis&qsSearchArea=searchText">colloidal synthesis; p://pubs.acs.org/action/doSearch?action=search&searchText=seeded+growth&qsSearchArea=searchText">seeded growth; p://pubs.acs.org/action/doSearch?action=search&searchText=ferromagnetism&qsSearchArea=searchText">ferromagnetism; p://pubs.acs.org/action/doSearch?action=search&searchText=fluorescence&qsSearchArea=searchText">fluorescence; p://pubs.acs.org/action/doSearch?action=search&searchText=core%E2%88%92shell&qsSearchArea=searchText">core鈭抯hell; p://pubs.acs.org/action/doSearch?action=search&searchText=zinc+oxide&qsSearchArea=searchText">zinc oxide; p://pubs.acs.org/action/doSearch?action=search&searchText=iron+oxide&qsSearchArea=searchText">iron oxide