Author(s):
Manaia, Eloísa Berbel [UNESP] ; Kaminski, Renata Cristina Kiatkoski ; Caetano, Bruno Leonardo [UNESP] ; Magnani, Marina [UNESP] ; Meneau, Florian ; Rochet, Amélie ; Santilli, Celso Valentim [UNESP] ; Briois, Valérie ; Bourgaux, Claudie ; Chiavacci, Leila Aparecida [UNESP]
Date: 2018
Persistent ID: http://hdl.handle.net/11449/175790
Origin: Oasisbr
Subject(s): Heterostructure; Quantum dots; Small angle X-ray scattering; Sol-gel; UV-vis spectroscopy; X-ray absorption spectroscopy; ZnO; ZnS; Heterostructure; Heterostructure; Quantum dots; Quantum dots; Small angle X-ray scattering; Small angle X-ray scattering; Sol-gel; Sol-gel; UV-vis spectroscopy; UV-vis spectroscopy; X-ray absorption spectroscopy; X-ray absorption spectroscopy; ZnO; ZnO; ZnS; ZnS
Description
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Society for Ambulatory Anesthesia
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
ZnO/ZnS heterostructures have emerged as an attractive approach for tailoring the properties of particles comprising these semiconductors. They can be synthesized using low temperature sol-gel routes. The present work yields insight into the mechanisms involved in the formation of ZnO/ZnS nanostructures. ZnO colloidal suspensions, prepared by hydrolysis and condensation of a Zn acetate precursor solution, were allowed to react with an ethanolic thioacetamide solution (TAA) as sulfur source. The reactions were monitored in situ by Small Angle X-ray Scattering (SAXS) and UV-vis spectroscopy, and the final colloidal suspensions were characterized by High Resolution Transmission Electron Microscopy (HRTEM). The powders extracted at the end of the reactions were analyzed by X-ray Absorption spectroscopy (XAS) and X-ray diffraction (XRD). Depending on TAA concentration, different nanostructures were revealed. ZnO and ZnS phases were mainly obtained at low and high TAA concentrations, respectively. At intermediate TAA concentrations, we evidenced the formation of ZnO/ZnS heterostructures. ZnS formation could take place via direct crystal growth involving Zn ions remaining in solution and S ions provided by TAA and/or chemical conversion of ZnO to ZnS. The combination of all the characterization techniques was crucial to elucidate the reaction steps and the nature of the final products.
Department of Drugs and Medicines School of Pharmaceutical Sciences São Paulo State University (UNESP)
Institut Galien University Paris-Sud The National Center for Scientific Research (CNRS) UMR 8612
Department of Chemistry Sergipe Federal University—Campus Itabaiana, Av. Vereador Olimpio Grande, s/n
Chemistry Institute of São Paulo State University UNESP, Prof. Francisco Degni Street, 55
Brazilian Synchrotron Light Laboratory (LNLS) Brazilian Center for Research in Energy and Materials (CNPEM)
Synchrotron Optimized Light Source of Intermediate Energy to LURE (SOLEIL), L’Orme des Merisiers, BP48
Department of Drugs and Medicines School of Pharmaceutical Sciences São Paulo State University (UNESP)
Chemistry Institute of São Paulo State University UNESP, Prof. Francisco Degni Street, 55
FAPESP: 2012/07570-4
Society for Ambulatory Anesthesia: 20131299
CAPES: ME 767-13
