tailieunhanh - Báo cáo hóa học: " Fabrication of Worm-Like Nanorods and Ultrafine Nanospheres of Silver Via Solid-State Photochemical Decomposition"

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: Fabrication of Worm-Like Nanorods and Ultrafine Nanospheres of Silver Via Solid-State Photochemical Decomposition | Nanoscale Res Lett 2009 4 471-479 DOI S11671-009-9267-0 NANO EXPRESS Fabrication of Worm-Like Nanorods and Ultrafine Nanospheres of Silver Via Solid-State Photochemical Decomposition S. Navaladian B. Viswanathan T. K. Varadarajan R. P. Viswanath Received 12 December 2008 Accepted 27 January 2009 Published online 21 February 2009 to the authors 2009 Abstract Worm-like nanorods and nanospheres of silver have been synthesized by photochemical decomposition of silver oxalate in water by UV irradiation in the presence of CTAB and PVP respectively. No external seeds have been employed for the synthesis of Ag nanorods. The synthesized Ag colloids have been characterized by UV-visible spectra powder XRD HRTEM and selected area electron diffraction SAED . Ag nanospheres of average size around 2 nm have been obtained in the presence of PVP. XRD and TEM analyses revealed that top and basal planes of nanorods are bound with 111 facets. Williamson-Hall plot has revealed the presence of defects in the Ag nanospheres and nanorods. Formation of defective Ag nanocrystals is attributed to the heating effect of UV-visible irradiation. Keywords Ag nanorods Nanospheres CTAB PVP Photochemical decomposition WH plot Introduction Silver nanoparticles have been known for the variety of applications in various fields such as catalysis electronics optics medicine and environment. Particularly Ag nanoparticles find applications in diagnostic biomedical optical imaging 1 molecular labeling 2 spectrally selective coating for the solar energy absorption 3 cancer therapy 4 and sensors for refractive index 5 and ammonia 6 . S. Navaladian B. Viswanathan T. K. Varadarajan R. P. Viswanath El National Centre for Catalysis Research Department of Chemistry Indian Institute of Technology Madras Chennai 600 036 India e-mail rpviswanath@ Moreover Ag nanoparticles are known for the antimicrobial 7 surface-enhanced Raman scattering SERS 8 and metal-enhanced fluorescence properties 9 . Silver