清华大学材料科学与工程研究院《材料科学论坛》
学术报告
题目/Title: 结构机理探究及性能调控的原子尺度结构设计 (Seeing atomic-scale structural origins and foreseeing new pathways to improved functional materials with aberration-corrected STEM)
报告人/Speaker：武海军 博士，李光耀博士后研究员 (Dr. Haijun Wu, Lee Kuan Yew Postdoctoral Fellowship)
报告人工作单位/Affiliation：新加坡国立大学 (National University of Singapore, NUS)
日期/Date：2019年7月5日（周五） 下午3:30
联系人/Contact：王轲老师（62786252）
报告地点/Location：清华大学逸夫技术科学楼A205学术报告厅
报告摘要/Abstract：
Structural defects in crystalline materials have been well acknowledged as the major parameters to optimize materials’ properties. Controlling and tuning these imperfections can lead to marked improvements in their functional properties. The atomic-scale defects have usually been ignored due to the difficulty of quantifying them via traditional methods. Aberration-corrected scanning transmission electron microscopy (STEM) has developed into the most powerful characterization and even fabrication platform for all materials, especially for functional materials with complex structural features that dynamically respond to external fields. Directly seeing and tuning all scales of defects has now become possible, including the critically important atomic-scale defects. Thoroughly understanding the nature and role of structural defects not only reveals the origin of the structure-property relations of existing high-performance materials, but more importantly, enables us to foresee new pathways to the design of new materials with enhanced properties.
I will show the achievements and new insights obtained from representative functional materials, including piezoelectrics/ferroelectrics, functional oxide interfaces, thermoelectrics, and electrocatalysts. STEM probe imaging was used for investigation into the quantitative atomic displacements of local polarization states in the rapidly evolving field of piezoelectric ceramics, where significant advance is being made to unveil the complex phase boundaries and physical origin of the remarkable piezoelectric properties. We can also visualize both intrinsic and extrinsic defects at the atomic scale, which are shown to play a dominant role in thermal and electrical transport properties, comparable to the widely accepted role of nanostructuring. The same applies to electrocatalysts, where various defects down to the atomic scale have led to much improved electrochemical performance. We highlight a universal strategy to optimize the properties of these functional materials, atomic-scale defect engineering.
作者简介/Speaker’s short biography：
武海军博士，新加坡国立大学李光耀博士后研究员（Lee Kuan Yew Postdoctoral Fellowship），博士毕业于新加坡国立大学材料系（2019.4），学士（2009）和硕士（2012）毕业于西安交通大学。荣获李光耀博士后基金（18万新币，2019）、新加坡总统奖学金（2017）、国家自费留学生奖（2018）、国际电镜协会青年科学家（IFSM Young Scientists ，2018）、全球青年科学家（GYSS Young Scientists，2019）和中国热电协会青年科学家（2014）。研究课题是运用先进电子显微镜技术研究功能材料的性能、结构和机理关系，所涉及的功能材料包括压电材料、热电材料、功能氧化物界面等。SCI论文约75篇，其中以一作（含共一）或通讯发表36篇，包括 Nat. Commun. (1), Energ. Environ. Sci. (7), J. Am. Chem. Soc. (6), Adv. Mater. (1), Adv. Energ./Funct. Mater. (5)，Nano Energy (4), Mater. Horiz.(1)，Nanoscale Horiz.(1), NPG Asia Mater. (1), Acta Mater. (3)等。ISI高被引文章共5篇。总被引用次数约3400次 (Google scholar)，H因子32 (Google scholar)。