Theoretical Studies on the Electronic Structure of Nano-graphenes for Applications in Nonlinear Optics  

作　　者：CHEN Kaichun ZHENG Xuelian YANG Cuicui TIAN Wei Quan LI Weiqi YANG Ling 

机构地区：[1]Chongqing Key Laboratory of Theoretical and Computational Chemistry,College of Chemistry and Chemical Engineering,Chongqing University,Huxi Campus,Chongqing 401331,P.R.China [2]School of Physics,Harbin Institute of Technology,Harbin 150001,P.R.China [3]Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,P.R.China [4]MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage,Institute of Theoretical and Simulational Chemistry,School of Chemistry and Chemical Engineering,Harbin Institute of Technology,Harbin 150001,P.R.China

出　　处：《Chemical Research in Chinese Universities》2022年第2期579-587,共9页高等学校化学研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.21673025,11974091,21203042,11574062);the Open Projects of Key Laboratory of Polyoxometalate Science of Ministry of Education(NENU)of China and the State Key Laboratory of Supramolecular Structure and Materials(JLU)of China(No.SKLSSM2021020).

摘　　要：In this work,azulene is introduced into nano-graphene with coronene center to enhance the second-order nonlinear optical(NLO)properties.The sum-over-states(SOS)model based calculations demonstrate that dipolar contributions are larger than octupolar contributions to the static first hyperpolarizability(〈β0〉)in most nano-graphenes except those with high symmetry(e.g.,a C2v nano-graphene has octupolar contributionsΦJ=3 up to 59.0%of the〈β0〉).Nano-graphenes containing two parallel orientating azulenes(i.e.,Out-P and Out-Ps)have large dipole moments,while their ground state is triplet.Introducing B/N/BN atoms into the positions with a high spin density transfers the ground state of Out-P and Out-Ps to closed-shell singlet,and the Out-Ps-2N has a large〈β0〉of 1621.67×10−30 esu.Further addition of an electron donor(NH2)at the pentagon end enhances the〈β0〉to 1906.22×10−30 esu.The two-dimensional second-order NLO spectra predicted by using the SOS model find strong sum frequency generations and difference frequency generations,especially in the near-infrared and visible regions.The strategies to stabilize the electronic structure and improve the NLO properties of azulene-defect carbon nanomaterials are proposed,and those strategies to engineer nano-graphenes to be semiconducting while maintaining theπ-framework are exten-dable to other similar systems.

关 键 词：Nonlinear optics Azulene-defect nano-graphene Two-dimensional second-order nonlinear optical spectrum Sum frequency generation Difference frequency generation 

分 类 号：O62[理学—有机化学]