电场调控的碳纳米管非线性光学开关及其管径效应  

Manipulating nonlinear optical properties of carbon nanotube via external electric field

作　　者：贺慧敏 杨辉[2] 李莹 李祥辉 李志儒[3] HE Hui-Min;YANG Hui;LI Ying;LI Xiang-Hui;LI Zhi-Ru(Department of Physics,Institute of Computational and Applied Physics,Taiyuan Normal University,Jinzhong 030619,China;Institute of Carbon Materials Science,Shanxi Datong University,Datong 037009,China;Laboratory of Theoretical and Computational Chemistry,Institute of Theoretical Chemistry,Jilin University,Changchun 130023,China;Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education,Fujian Provincial Key Laboratory of Photonics Technology,Fujian Normal University,Fuzhou 350007,China)

机构地区：[1]太原师范学院物理系计算和应用物理研究所,晋中030619 [2]山西大同大学炭材料研究所,大同037009 [3]吉林大学理论化学研究所,长春130023 [4]福建师范大学医学光电科学与技术教育部重点实验室福建省光子技术重点实验室,福州350007

出　　处：《原子与分子物理学报》2022年第5期62-70,共9页Journal of Atomic and Molecular Physics

基　　金：山西省高等学校科技创新项目(2020L0507)。

摘　　要：本文借助密度泛函理论方法获得了五个不同管径碳纳米管在外电场作用下的最优几何结构和相应的性质,研究了外电场对碳纳米管的结构和性质的调控作用.结果表明外电场导致了碳纳米管内部的电荷转移,引起了碳纳米管第一超极化率(β_(0))的急剧增大.例如CNT(6,3),当电场从0增大到工作电场F_(w)=80×10^(-4)au时,碳纳米管的β_(0)值从0 au可增大到最大83695 au,导致了极大的β_(0)对比,因此碳纳米管成为新型的非线性光学(NLO)开关.新型NLO开关的管径效应表明,较大管径的碳纳米管具有更优的NLO开关性质.除此之外,电子吸收光谱表明这些碳纳米管具有小于300 nm和大于2500 nm的光学工作区,因此碳纳米管可成为一类新的灵敏、快速、可逆的紫外兼红外的NLO开关.In the present work,optimized geometric structures with all real frequencies under various external electric field strengths from 0 to 200×10^(-4)au are obtained for five carbon nanotubes with the different diameters at the B3LYP/6-31G*level,and the relationships between their electronic structures and properties are also studied.The results show that external electric fields hardly change geometric structures of these nanotubes and they have larger stability within the range of our studied electric field.Besides,it is shown that the effect of the external electric field induces an intramolecular charge transfer,which can lead to a considerable increase of first hyperpolarizabilityβ_(0).For CNT(3,3),CNT(4,3),and CNT(5,3)carbon nanotubes,β_(0)(F)(β_(0) under external electric field)gradually increases with increasing external electric field strength.Thus,when F=200×10^(-4) au,they have the largestβ_(0)(F)of 3832 au,34507 au,and 83695 au,respectively.However,for CNT(6,3)and CNT(7,3),the dependence ofβ_(0)(F)with respect to the external electric field strength F can be presented by a monopeak curve.Moreover,these carbon nanotubes have also excellent ultraviolet(UV,≤300 nm)and infrared(IR,≥2500 nm)transparency.Therefore,these carbon nanotubes can act as candidates for UV/IR NLO(Nonlinear optical)switches.

关 键 词：碳纳米管 外电场 电荷转移 第一超极化率 非线性光学开关 

分 类 号：O641[理学—物理化学]