报告一：
报告题目: Electronic structure Design for Photo-energy Conversion Materials (氧化物太阳能转化材料电子结构的设计)
开始时间: 2016-01-11 10:00:00
报告地点： 材料学院教工活动中心
报 告 人: 北京航空航天大学 郝维昌 教授
备注:
郝维昌，博士，教授，博士生导师，1997年东北大学获学士学位，2003年兰州大学获博士学位，2003年7月-2005年6月在北京航空航天大学物理系做博士后，出站后留校工作任讲师、副教授、教授。2008、2014年两次在东京工业大学材料专攻任Research Fellow；2011以来多次在澳大利亚卧龙岗大学超导与电子材料研究所任Visiting Fellow。研究兴趣为氧化物材料电子结构，氧化物材料在环境及能源领域中的应用，二维纳米材料及器件。2012年获教育部自然科学二等奖(排名第3)。在PRB、APL、ACS Cata. J. Phys. Chem. C、ACS App. Mater. Interface等杂志上发表论文80余篇，论文被他人引用800余次。获得8项国家发明专利授权。
报告简介：Recently, it was found that there are three variations that occur in band structures when a p-block element is incorporated, as shown. In the first case, the top of the VB is up-shifted by incorporating an extra p state in the VB or by hybridization of d/s states with O 2p. In the second case, sp hybridization leads to a dispersive CB and lowers the bottom of the CB. Some solid solutions are good examples of band tuning via combination of the cases. As a result, the VB is up-shifted, and the CB is down-shifted simultaneously. It turns out that the p orbital plays an important role in the states of charge carriers for the above-mentioned high performance photocatalysis. Since the CB constructed with d orbital is flat in contrast to the sp hybridization states, we propose a new strategy to explore high-performance visible-light photocatalysis using only p-block elements, based on the following conceptual design. The p-block elements consist of partially filled p states and d0 or d10 electronic states. If we construct a compound with p-block elements, only the s and p states can form the VB and CB via sphybridization. As a result, d orbital electrons are lowered to deep levels, leaving only p states for VB and sp states for CB. These electronic structural properties are ideal for photocatalytic reactions.In this talk, we report visible-light photocatalysis BiOX(X=Cl\Br\I),and Bi24O31x10 (X=Cl\Br)with the CB and VB formed only by sp and p states, since Bi, O and Br are all p-block elements[1-3]. We observed high redox activity and found that high photocatalytic activity was caused by the charge transfer between p and sp states.
参考文献：
1. ACS Appl. Mater. Interfaces 2015, 7, 27592
2. J. Phys. Chem. C 2015, 119: 14094
3. Energy Environ. Sci. 2015,8:1231
4. Scientific Reports 2014,4:7384
5. ACS Catal. 2014,4:954-961
报告二：
报告题目: Silicene: A Silicon-based Dirac Fermion 2D material (硅烯：具有狄拉克费米子的二维单原子层硅材料)
开始时间: 2016-01-11 11:00:00
报告地点: 实验一楼大会议室、材料学院教工活动中心
报 告 人: 澳大利亚卧龙岗大学 杜轶 研究员
备注:
杜轶，博士，研究员，2011年毕业于澳大利亚卧龙岗大学（University of Wollongong）获得材料学博士学位。现在作为研究员供职于澳大利亚卧龙岗大学澳大利亚创新材料研究院（AIIM）和超导与电子材料研究所（ISEM）。他是扫描隧道显微镜、原子力显微镜实验室及低温物理实验室负责人。2015年，他被邀请担任英国自然杂志出版集团（Nature Publishing Group）下属《Scientific Reports》的编委成员。他的研究领域主要集中在开发新型二维材料及其表面物理化学性质的研究。截至2015年，杜轶研究院已著有专著章节两部，发表高水平论文（包括Nat. Commun.、Phys. Rev. Lett.、Adv. Mater.、Phys. Rev. B、ACS Nano、Adv. Funct. Mater.、ACS Catalysis、Sci. Rep.和Appl. Phys. Lett.）50多篇。
报告内容简介：Silicene is a monolayer allotrope of silicon atoms arranged in a honeycomb structure with massless Dirac fermion characteristics, similar to graphene. It ensures development of silicon-based multifunctional nanoelectronic and spintronic devices operated at room temperature due to strong spin-orbit coupling. Nevertheless, until now, silicene could only be epitaxially grown on conductive substrates. The strong silicene-substrate interaction may depress its superior electronic properties. In my talk, I will briefly review the progress in research on silicene. And then, some new results will be reported, in which a quasi-free-standing silicene layer that has been successfully obtained through oxidization of bilayer silicene on the Ag(111) surface. The oxygen atoms intercalate into the underlayer of silicene, which can isolate the top layer of silicene from the substrate. In consequence, the top layer of silicene exhibits the signature of a 11 honeycomb lattice and hosts massless Dirac fermions due to much less interaction with the substrate. Furthermore, some exotic properties in silicene discovered by my group will be introduced. They are expected to promote performance of silicene-based electronic devices.