Caetano, Bruno Leonardo [UNESP]Santilli, Celso Valentim [UNESP]Pulcinelli, Sandra Helena [UNESP]Briois, Valerie2014-05-202014-05-202011-01-01Phase Transitions. Abingdon: Taylor & Francis Ltd, v. 84, n. 8, p. 714-725, 2011.0141-1594http://hdl.handle.net/11449/25507Time-resolved X-ray absorption-fine structure (Quick-XAFS) and UV-Vis absorption spectroscopies were combined for monitoring simultaneously the time evolution of Zn-based species and ZnO quantum dot (Qdot) formation and growth during the sol-gel synthesis from zinc oxy-acetate precursor solution. The time evolution of the nanostructural features of colloidal suspension was independently monitored in situ by small angle X-ray scattering (SAXS). In both cases, the monitoring was initialized just after the addition of NaOH solution (B = [OH]/[Zn] = 0.5) to the precursor solution at 40 degrees C. Combined time-resolved Quick-XAFS and UV-Vis data showed that the formation of ZnO colloids from the zinc oxy-acetate consumption achieves a quasi-steady-state chemical equilibrium in less than 200s. Afterwards, the comparison of the ZnO Qdots size and Guinier gyration radius evidences a limited aggregation process coupled to the Qdots growth. The analysis of the experimental results demonstrates that the nanocrystal coalescence and Ostwald ripening control the kinetics of the Qdot growth.714-725engtime-resolved X-ray absorptionUV-Visible absorptionSAXSquantum dots formationZnOsol-gelArtigo10.1080/01411594.2011.569318WOS:000299703700005Acesso restrito558429868187086599712025852869670000-0002-8356-8093