报告题目：Symmetry Making and Breaking in Seeded Growth of Metal Nanocrystals
报告人：Sara Skrabalak教授（Indiana University, USA）
Crystal growth theory predicts that heterogeneous nucleation will occur preferentially at defect sites, such as the vertices rather than the faces of shape-controlled seeds. Platonic metal solids are generally assumed to have vertices with nearly identical chemical potentials, and also nearly identical faces, leading to the useful generality that heterogeneous nucleation preserves the symmetry of the original seeds in the final product. This presentation will discuss how this generality can be used to access stellated metal nanocrystals with high and tunable symmetries for applications in plasmonics. This presentation will also discuss the limits of this generality in the extreme of low supersaturation. A strategy for favoring localized deposition that differentiates between both different vertices and different edges or faces, i.e., regioselective deposition, will be demonstrated. Such regioselective heterogeneous nucleation was achieved at low supersaturation by a kinetic preference for high-energy defect-rich sites over lower-energy sites. This outcome was enhanced by using capping agents to passivate facet sites where deposition was not desired. Collectively, the results presented provide a model for breaking the symmetry of seeded growth and for achieving regioselective deposition.
Sara Skrabalak received her B.A. in chemistry from Washington University in St. Louis in 2002 where she conducted research with Professor William E. Buhro. She then moved to the University of Illinois at Urbana-Champaign where she completed her Ph.D. in chemistry in fall of 2006 under the tutelage of Professor Kenneth S. Suslick. After conducting postdoctoral research at the University of Washington – Seattle with Professors Younan Xia and Xingde Li, she began on the faculty at Indiana University – Bloomington in 2008. She is currently the James H. Rudy Professor at Indiana University.
She is a recipient of both NSF CAREER and DOE Early Career Awards. She is a 2012 Research Corporation Cottrell Scholar, a 2013 Sloan Research Fellow, a 2014 Camille Dreyfus Teacher-Scholar and 2017 Guggenheim and Fulbright Fellows. In 2014, she received the ACS Award in Pure Chemistry and in 2017 was the recipient of the Frontiers in Research Excellence & Discovery Award from Research Corporation. Her group is developing new synthetic methods to solid materials with defined shapes and architecture then studying the properties of the materials as they are applied to applications in energy science, chemical sensing, and secured electronics. She has served in the advisory board for several journals, such as Nanoscale, ChemNanoMat, etc.