清華大學材料科學與工程研究院《材料科學論壇》

學術報告

題目/Title: 結構機理探究及性能調控的原子尺度結構設計 (Seeing atomic-scale structural origins and foreseeing new pathways to improved functional materials with aberration-corrected STEM)

報告人/Speaker：武海軍 博士，李光耀博士後研究員 (Dr. Haijun Wu, Lee Kuan Yew Postdoctoral Fellowship)

報告人工作單位/Affiliation：新加坡國立大學 (National University of Singapore, NUS)

日期/Date：2019年7月5日（周五） 下午3:30

聯系人/Contact：王轲老師（62786252）

報告地點/Location：清華大學逸夫技術科學樓A205學術報告廳

報告摘要/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.

作者簡介/Speaker’s short biography：
武海軍博士，新加坡國立大學李光耀博士後研究員（Lee Kuan Yew Postdoctoral Fellowship），博士畢業于新加坡國立大學材料系（2019.4），學士（2009）和碩士（2012）畢業于西安交通大學。榮獲李光耀博士後基金（18萬新币，2019）、新加坡總統獎學金（2017）、國家自費留學生獎（2018）、國際電鏡協會青年科學家（IFSM Young Scientists ，2018）、全球青年科學家（GYSS Young Scientists，2019）和中國熱電協會青年科學家（2014）。研究課題是運用先進電子顯微鏡技術研究功能材料的性能、結構和機理關系，所涉及的功能材料包括壓電材料、熱電材料、功能氧化物界面等。SCI論文約75篇，其中以一作（含共一）或通訊發表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。總被引用次數約3400次 (Google scholar)，H因子32 (Google scholar)。