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报告内容摘要：
Monodisperse inorganic nanocrystals have been intensively investigated in recent years, both because of fundamental scientific interest and technological applications arising from the unique properties in reduced dimension. In particular, the spinel ferrites of composition MFe2O4 (M=Co, Ni, Mn, Fe, etc.) exhibit interesting magnetic, magnetoresistive, and magneto-optical properties that are potentially useful for a broad range of applications, including magnetoelectric devices, drug delivery, ferrofluidics, etc. Their magnetic properties can be systematically varied by changing the identity of the divalent M2+ cation or by partial substitution. The properties can additionally be tuned by controlling the shape, size and crystallinity of the nanocystals. Another class of spinel nanocrystals that remain largely unexplored are the chromium-based spinel chalcogenides, ACr2X4 (A = Cu, Cd, Hg, Fe, Co; X = S, Se, Te), which are ferro/ferromagnetic insulators, semiconductors, or even metals that display unique properties in the bulk. We have synthesized monodisperse nanocrystals of a number of spinel ferrites and chalcogenides using facile solution-based methods and investigated their magnetic properties. The synthesis of the chalcogenides has been further expanded to semiconducting nanocrystals of varying compositions and band gaps, such as CuInxGa1-xS2 and CuInxGa1-xSe2, with different anisotropic shapes and crystal structures. Colloidal suspensions of the nanocrystals are attractive for use as inks for low-cost fabrication of thin film solar cells by spin or spray coating.

报告人简介：
Prof. Gupta is the MINT Professor at the University of Alabama and is affiliated with the Chemistry and Chemical & Biological Engineering Departments. He joined the University in 2004, prior to which he was a Research Staff Member and Manager in the Physical Science Department at the IBM Thomas J. Watson Research Center, New York. Prof. Gupta received his undergraduate degree from the Indian Institute of Technology and Ph.D. degree in chemical physics from Stanford University. He has worked in a wide range of materials-related topics, including laser processing, high temperature superconductors, semiconducting oxides and chalcogenides, dielectrics and magnetic materials, and their device applications. Prof. Gupta has published over 300 journal articles and holds 30 US patents. He is a fellow of the American Physical Society (APS) and the American Association for the Advancement of Science (AAAS). In 2010 Prof. Gupta received the Humboldt Research Award in recognition of his exceptional and sustained contributions to research on magnetism and superconductivity of oxide-based materials.