tailieunhanh - Báo cáo hóa học: "Photochemically reduced polyoxometalate assisted generation of silver and gold nanoparticles in composite films: a single step route"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Photochemically reduced polyoxometalate assisted generation of silver and gold nanoparticles in composite films: a single step route | Nanoscale Res Lett 2007 2 175-183 DOI s11671-007-9050-z NANO EXPRESS Photochemically reduced polyoxometalate assisted generation of silver and gold nanoparticles in composite films a single step route Sangaraju Shanmugam Balasubramanian Viswanathan Thirukkallam K. Varadarajan Published online 13 March 2007 to the authors 2007 Abstract A simple method to embed noble metal Ag Au nanoparticles in organic-inorganic nanocomposite films by single step method is described. This is accomplished by the assistance of Keggin ions present in the composite film. The photochemically reduced composite film has served both as a reducing agent and host for the metal nanoparticles in a single process. The embedded metal nanoparticles in composites film have been characterized by UV-Visible TEM EDAX XPS techniques. Particles of less than 20 nm were readily embedded using the described approach and monodisperse nanoparticles were obtained under optimized conditions. The fluorescence experiments showed that embedded Ag and Au nanoparticles are responsible for fluorescence emissions. The described method is facile and simple and provides a simple potential route to fabricate self-standing noble metal embedded composite films. Keywords Polyoxometalates Organic-inorganic nanocomposite Silver Gold Fluorescence Introduction In recent years the synthesis and characterization of nanoparticles have received attention because of their distinctive properties and potential uses in various fields like microelectronics 1 photocatalysis 2 magnetic devices 3 and powder metallurgy 4 . The intrinsic S. Shanmugam B. Viswanathan El T. K. Varadarajan Department of Chemistry Indian Institute of Technology Madras Chennai 600 036 India e-mail bvnathan@ properties of a metal nanoparticle are mainly determined by size shape composition crystallinity and morphology 5 . A number of methods have been developed to prepare noble metal colloids such as chemical reduction with or without stabilizing