The Critical Role of Thioacetamide Concentration in the Formation of ZnO/ZnS Heterostructures by Sol-Gel Process

Author(s)

Manaia, Eloisa Berbel ^{[1, 2]} ; Kiatkoski Kaminski, Renata Cristina ^[3] ; Caetano, Bruno Leonardo ^[1] ; Magnani, Marina ^[4] ; Meneau, Florian ^[5] ; Rochet, Amelie ^[5] ; Santilli, Celso Valentim ^[4] ; Briois, Valerie ^[6] ; Bourgaux, Claudie ^[2] ; Chiavacci, Leila Aparecida ^[1]

Affiliation

^[1] Sao Paulo State Univ, UNESP, Sch Pharmaceut Sci, Dept Drugs & Med, BR-14800903 Araraquara, SP - Brazil

^[2] Univ Paris Sud, CNRS, Inst Galien, Natl Ctr Sci Res CNRS, UMR 8612, F-92296 Chatenay Malabry - France

^[3] Univ Fed Sergipe, Dept Chem, Campus Itabaiana, Av Vereador Olimpio Grande S-N, BR-49506036 Itabaiana, SE - Brazil

^[4] Sao Paulo State Univ, UNESP, Chem Inst, Prof Francisco Degni St 55, BR-14800060 Araraquara, SP - Brazil

^[5] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Synchrotron Light Lab LNLS, BR-13083970 Sao Paulo - Brazil

^[6] Synchrotron Optimized Light Source Intermediate E, BP48, F-91192 Gif Sur Yvette - France

• Document type: Journal article
• Source: NANOMATERIALS; v. 8, n. 2 FEB 2018.
• Web of Science Citations: 2

Abstract

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. (AU)

• FAPESP's process: 12/07570-4 - Zinc based quantum dots and double salts incorporated in liposome for image and vectorization of anticancer drug
• Grantee: Eloísa Berbel Manaia
• Support Opportunities: Scholarships in Brazil - Doctorate