时间：2016年12月26日9:30
地点：科技创新大楼C501室

2D Materials and Devices: Opportunities and Challenges
Xiangfeng Duan（段镶锋）
Department of Chemistry and Biochemistry, California Nanosystems Institute, University of California, Los Angeles, CA 90095, USA

Abstract:

Two-dimensional layered materials (2DLMs), such as graphene or molybdenum disulfide, represent an ideal 2D material system for exploring fundamental chemistry and physics at the limit of single atomic thickness. The covalently bonded atomic layers in 2DLMs are bound weakly to each other through van der Waals interactions, which offers considerable flexibility to isolate, mix and match individual atomic layers without the constraints of lattice and processing compatibility. It can therefore open up vast possibilities for nearly arbitrarily combining multiple materials and integrating distinct properties at the atomic scale, and thus enabling entirely new opportunities beyond the reach of existing materials. Here I will focus my discussion on exploring these 2D materials and their heterostructures as new platforms for the creation of a wide of electronic and optoelectronic devices with unique functions or unprecedented performance. Examples discussed include: high-speed transistors; a new design of vertical transistors for ultra-flexible electronics; and a series of of tunable photonic devices.

Bio:

Dr. Duan received his B.S. Degree from University of Science and Technology of China in 1997, and Ph.D. degree from Harvard University in 2 002. He was a Founding Scientist and then Manager of Advanced Technology at Nanosys Inc., a nanotechnology startup founded based partly on his doctoral research. Dr. Duan joined UCLA with a Howard Reiss Career Development Chair in 2008, and was promoted to Associate Professor in 2012 and Full Professor in 2013. Dr. Duan’s research interest includes nanoscale materials, devices and their applications in future electronics, energy technologies and biomedical science. A strong emphasis is placed on the hetero-integration of multi-composition, multi-structure and multi-function at the nanoscale, and by doing so, creating a new generation of integrated nanosystems with unprecedented performance or unique functions to break the boundaries of traditional technologies. Dr. Duan has published over 180 papers in leading scientific journals, and holds over 40 issued US patents. For his pioneer research in nanoscale science and technology, Dr. Duan has received many awards, including MIT Technology Review Top-100 Innovator Award, NIH Director’s New Innovator Award, NSF Career Award, Alpha Chi Sigma Glen T. Seaborg Award, Herbert Newby McCoy Research Award, US Presidential Early Career Award for Scientists and Engineers (PECASE), ONR Young Investigator Award, DOE Early Career Scientist Award, Human Frontier Science Program Young Investigator Award, Dupont Young Professor, Journal of Materials Chemistry Lectureship, International Union of Materials Research Society and Singapore Materials Research Society Young Researcher Award, the Beilby Medal and Prize, and Nano Korea Award.

Molecular Specificity Guided NanoCrystal Growth, Assembly and Catalysis
Yu Huang
Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095-1595,http://yhuang.seas.ucla.edu
e-mail:yhuang@seas.ucla.edu

Material formation in nature is precisely controlled in all aspects from crystal nucleation, growth to assembly to deliver superior functions. Specific biomolecule-material interactions have been hypothesized to play important roles in these processes. Proteins, polymers and small molecules have been extensively explored to replicate the degree of control in material formation in vitro and for nonbiogenic materials. However the organic-inorganic interfacial interaction is still far from being understood which hinders the further advancement of biomimetic material formation. In this talk I will share our efforts on decoding the myth of biomolecular specificity to material surface and their roles in controlling crystal nucleation and growth. The selection of facet specific short peptides and their abilities in guiding predictable morphology control of Pt nanocrystals will be first demonstrated. Then detailed experimental and theoretical studies on binding mechanism will be discussed. Based on mechanistic understanding, we designed small molecules bearing molecular signature for facet specific adsorption to modulate the nucleation/growth of the Pt nanocrystals to deliver the expected nanostructures and functions. At the end of talk I will share our recent research on improving catalytic functions of nanocrystals through synthetic design. These studies open up opportunities in understanding the molecular details of inorganic-organic interface interaction, which can one day lead to the development of a library of molecular functions for biomimetic materials design and engineering.

Short Biography:
Professor Huang receives her Ph.D in physical chemistry from Harvard University and her B.S. in chemistry from University of Science and Technology of China. At UCLA she explores the unique technological opportunities that result from the structure and assembly of nanoscale building blocks. Focusing on the molecular level, she conducts research to unravel the fundamental principles governing nanoscale material synthesis and assembly; and utilizes such principles to design nanostructures and nanodevices with unique functions and properties to address critical challenges in electronics, energy science and biomedicine. Recognitions she received include the World’s Top 100 Young Innovators, the Sloan Fellowship, the PECASE, DARPA Young Faculty Award and the NIH New Innovator Award.