講座編號(hào)：jz-yjsb-2022-y012

講座題目：Band Engineering in Two-Dimensional Covalent Organic Frameworks

主 講 人：倪曉娟 博士 美國(guó)亞利桑那大學(xué)博士后

講座時(shí)間：2022年4月22日（星期五）上午11:00

講座地點(diǎn)：騰訊會(huì)議，會(huì)議ID：256 844 581

參加對(duì)象：人工智能學(xué)院師生、對(duì)報(bào)告感興趣的師生

主辦單位：人工智能學(xué)院、研究生院

主講人簡(jiǎn)介：

倪曉娟博士于2020年在美國(guó)猶他大學(xué)獲得材料科學(xué)與工程專業(yè)博士學(xué)位，導(dǎo)師為猶他大學(xué)榮譽(yù)教授（distinguished professor）Prof. Liu Feng（2015-2021年Physical Review Letters期刊Divisional Associate Editor）。倪曉娟博士目前為美國(guó)亞利桑那大學(xué)博士后，合作導(dǎo)師為有機(jī)太陽(yáng)能電池領(lǐng)域知名專家Jean-Luc Brédas教授。倪博士的研究方向是金屬-有機(jī)和共價(jià)-有機(jī)框架的電子、磁性和拓?fù)湫再|(zhì)，以及用于電子和自旋電子應(yīng)用的拓?fù)洳牧希褚言贛aterials Horizon、Chemistry Materials、Physical Review B等國(guó)際知名期刊上發(fā)表了20多篇同行評(píng)議的研究文章。獲得的獎(jiǎng)項(xiàng)包括猶他大學(xué)工程學(xué)院最佳博士論文獎(jiǎng)等，多次參加美國(guó)物理學(xué)會(huì)APS報(bào)告。

主講內(nèi)容：

Two-dimensional covalent organic frameworks (2D-COFs), also referred to as 2D polymer networks, display unusual electronic-structure characteristics, which can significantly enrich and broaden the fields of electronics and spintronics. In this presentation, my objective is to lay the groundwork for the conceptual description of the fundamental relationships among the COF electronic structures, the symmetries of their 2D lattices, and the frontier molecular orbitals (MOs) of their core and linker components. We focus on monolayers of hexagonal COFs and use tight-binding model analyses to highlight the critical role of the frontier-MO symmetry, in addition to lattice symmetry, in determining the nature of the electronic bands near the Fermi level. We rationalize the intriguing feature that, when the core unit has degenerate highest occupied MOs [or lowest unoccupied MOs], the COF highest valence band [or lowest conduction band] is flat but degenerate with a dispersive band at a high-symmetry point of the Brillouin zone; the consequences of having such band characteristics are briefly described. Multi-layer and bulk 2D COFs are found to maintain the salient features of the monolayer electronic structures albeit with a reduced bandgap due to the interlayer coupling. This study is thus meant to provide an effective framework for the engineering of flat and Dirac bands in 2D polymer networks. (Materials Horizons 9, 88-98, 2022)