报告题目：Cooperative Self-assembly of Metal-Organic Complexes on Solid Surfaces

报 告 人：Quanmin Guo，School of Physics and Astronomy, University of Birmingham

报告时间：2014年4月17日15：30

报告地点：物理系三楼报告厅

报告摘要：Self-assembly of supramolecular structures represents one of the most promising and practical routes for bottom-up nanotechnology. During the last decade, there has been a rapid growing interest in transferring supramolecular chemistry to solid surfaces for a number of reasons. There is the technological need for anchoring molecular structures on a substrate for the purpose of device fabrication. In terms of fundamental studies, there are a large number of characterization techniques particularly suitable for probing molecules attached to solid surfaces. Among them are, the scanning tunnelling microscopy (STM) and the atomic force microscopy (AFM), both capable of imaging molecules with atomic resolution and hence providing direct information on bonding mechanisms. Moreover, the solid surface itself plays a role in the assembly process, offering the opportunity to build supramolecular architectures not viable in liquid environment. In this talk, I will discuss the process of growing metal-molecule complexes based on global optimization. What I mean by global optimization is that a number of metal atoms and molecules with some specific metal/molecule ratio interact with one another leading to the formation of a minimum energy complex. Such a metal-organic complex behaves like a giant molecule with well-defined geometric structure, similar to the systems of magic number clusters. The complex is stabilized by a rather “diffusive” interaction, instead of specific and directional interaction such as in hydrogen bonding or ligand-metal coordination. The example that I will show you is a Au-C60 complex consisting of 19 Au atoms and 7 C60 molecules formed on the (111) surface of gold. The system is studied using a variable temperature scanning tunnelling microscopy in vacuum.