Xuefeng GUO
Peking University, China
Title : Interface Effects in Molecular Devices: From Concept to Functions
Abstract :

Interface engineering proves to be an efficient and promising route for controlling the doping effect, improving the device performance and even installing new functionality. In this talk, I will mainly detail universal methodologies to create nanogapped point contacts formed form either single-walled carbon nanotubes (SWNTs) or single-layer graphene (SLG) for improving electrode/semiconductor interfaces. These contacts are formed by electron beam lithography and precise oxygen plasma etching. Through robust amide linkages, functional molecular bridges with diamines are covalently wired into carboxylic acid-functionalized nanogaps to afford single molecule devices with desired functionalities. We have tested this approach to achieve label-free, realt-time, ultrasensitive detections in biological systems, including DNA hybridization, DNA-protein interaction, and biotin/streptavidin binding. One key advantage of this approach to biosensing is the ability to form a well-defined chemical linkage between a molecular wire and a probe molecule. Furthermore, because it is constructed from a single molecule, each device can monitor individual binding events. On the other hand, by using these carbon-based electrodes, we significantly reduced the contact resistance and thus realized stimuli-responsive organic nanotransistors with high-performance. These studies apparently provide the deeper understanding of the interplay between molecular structure, assembly, and emergent functions at the molecular level and consequently novel insights into designing novel optoelectronic devices.

Biography :

Dr. Xuefeng Guo received his Ph.D. in 2004 from the Institute of Chemistry, Chinese Academy of Science, Beijing. From 2004 to 2007, he was a postdoctoral research scientist at the Columbia University Nanocenter. He joined the faculty as a professor under “Peking 100-Talent” Program at Peking University in 2008. In 2012, he won the national science funds for distinguished young scholars of China. He has over 85 scientific papers, including Science, Acc. Chem. Res., Chem. Soc. Rev., Nature Nanotech., PNAS, Angew. Chem. Int. Ed., and JACS et. al. He was awarded several precious prizes, such as the National Top 100 Excellent Ph. D. Thesis Award in China, Beijing Scientific New Star Award, and the Youth Prize in Chemistry of the Chinese Chemical Society, et. al..

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