Synthesis and characterization of organic-inorganic hybrid materials prepared by sol-gel and containing ZnxCd1-xS nanoparticles prepared by a colloidal method

Nanocomposite materials based on a hybrid organic–inorganic ureasilicate matrix doped with ZnxCd1 xS nanoparticles were prepared. ZnxCd1 xS nanoparticles with different compositions (Zn/Cd mole ratio) were prepared through a colloidal method using reverse micelles. Previously to dispersion within the matrix precursors used to prepare the hybrid gel composite, the nanoparticles surface was modified in order to improve compatibility and stability with the matrix and to assure the preservation of the original optical properties of the nanoparticles. The matrix was obtained by the reaction between a silicon alkoxide modified by an isocyanate group and a di-amine functionalized oligopolyoxyethylene (Jeffamine ED-600), which by subsequent hydrolysis and condensation reactions formed a mechanically stable and highly transparent solid network containing the ZnxCd1 xS nanoparticles. The materials were characterized by absorption, steady-state and time-resolved photoluminescence spectroscopy and by HRTEM. The obtained nanocomposites show a high transparency in the visible range accounting for the good dispersion of the nanoparticles within the matrix. The results obtained confirmed the preservation of the original optical properties of the nanoparticles after their incorporation into the ureasilicate matrix, showing that the developed method is suitable for the production of materials with potential applications in which it is necessary to take advantage of the optical properties of the nanoparticles incorporated. The HRTEM analysis confirmed that the dispersed nanoparticles show a high level of crystallinization.This work has been partially supported by the Fundacao para a Ciencia e a Tecnologia (FCT). L.F. Goncalves thanks the FCT for the PhD grant SFRH/BD/38262/2007. The authors gratefully acknowledge the financial support by Centro de Quimica [project F-COMP-01-0124-FEDER-022716 (ref. FCT Pest-C/Qui/UI0686/2011)-FEDER-COMPETE] and Centro de Fisica (Universidade do Minho). The authors would like to thank the Electron Microscope Unit of the Mark Wainwright Analytical Centre at The University of New South Wales, for scientific and technical suppor