物理化学学报 >> 2013, Vol. 29 >> Issue (12): 2534-2542.doi: 10.3866/PKU.WHXB201310292

理论与计算化学 上一篇    下一篇

有机晶体材料DAST和DSTMS的电子结构与光学性质

吴仁珍1, 方振兴1, 刘平1, 曹全贞1, 邱美1, 李奕1,2, 陈文凯1, 黄昕1, 章永凡1,2   

  1. 1 福州大学化学化工学院, 福州 350108;
    2 福建省光催化重点实验室—省部共建国家重点实验室培育基地, 福州 350002
  • 收稿日期:2013-07-09 修回日期:2013-10-28 发布日期:2013-11-28
  • 通讯作者: 章永凡 E-mail:zhangyf@fzu.edu.cn
  • 基金资助:

    国家自然科学基金(90922022, 21373048), 中国工程物理研究院高能激光科学与技术重点实验室开放基金(2012HCF05), 福建省自然科学基金(2013J06004)和福州大学科技发展基金(2012-XQ-11)资助项目

Electronic Structures and Optical Properties of Organic DAST and DSTMS Crystal Materials

WU Ren-Zhen1, FANG Zhen-Xing1, LIU Ping1, CAO Quan-Zhen1, QIU Mei1, LI Yi1,2, CHEN Wen-Kai1, HUANG Xin1, ZHANG Yong-Fan1,2   

  1. 1 College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350108, P. R. China;
    2 State Key Laboratory Breeding Base of Photocatalysis, Fuzhou 350002, P. R. China
  • Received:2013-07-09 Revised:2013-10-28 Published:2013-11-28
  • Contact: ZHANG Yong-Fan E-mail:zhangyf@fzu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (90922022, 21373048), Open Foundation of Key Laboratory for High-Energy Laser Science of China Academy of Engineering Physics (2012HCF05), Natural Science Foundation of Fujian Province for Distinguished Young Investigator Grant, China (2013J06004), and Scientific Development Fund of Fuzhou University, China (2012-XQ-11).

摘要:

采用基于赝势平面波基组的密度泛函理论(DFT)方法, 研究了有机晶体材料4-(4-二甲氨基苯乙烯基)甲基吡啶对甲苯磺酸盐(DAST)和4-(4-二甲氨基苯乙烯基)甲基吡啶2, 4, 6-三甲基苯磺酸盐(DSTMS)的电子结构和光学性质. 结果表明, 两种化合物具有相似的能带结构, 其中价带顶和导带底分别含有较多二甲氨基和甲基吡啶中N原子的2p轨道成分. 在线性光学性质方面, 两种化合物具有较高的双折射率(Δn>0.5), 在中远红外区均具有较好的透过性能. 在二阶非线性光学性质方面, 该类晶体具有较强的二阶倍频(SHG)效应, 静态倍频系数d11约为150 pm·V-1. 由能带结构分析结果可知, 体系的SHG效应与推拉电子基团之间的电荷转移密切相关, 同时乙烯桥键在该电子转移过程中也起着重要作用.

关键词: 有机晶体, 电子结构, 二阶倍频效应, 密度泛函理论

Abstract:

The electronic structures and optical properties of 4-N,N-dimethylamino-4'-N'-methylstilbazolium tosylate (DAST) and 4-N,N-dimethylamino-4'-N'-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) were investigated using density functional theory based on the plane wave basis set. The results indicated that the two compounds showed similar band structures, and the top of the valence band and the bottom of the conductive band mainly originated from the N 2p states of dimethylamino and methylpyridine, respectively. In terms of the linear optical properties, the birefringence indexes, Δn, of the two compounds were very large (Δn>0.5), and they exhibited good light transmission in the mid-and far-infrared regions. With regard to second-order nonlinear optical characteristics, the DAST and DSTMS crystals showed strong second harmonic generation (SHG) responses, and the corresponding SHG coefficients (d11) were about 150 pm·V-1. Analysis of the band structures showed that the SHG responses of the two compounds were closely related to charge transfers between electron-donating and electron-withdrawing groups. Ethylene bridging also played an important role in the charge transfer process.

Key words: Organic crystal, Electronic structure, Second harmonic generation response, Density functional theory

MSC2000: 

  • O641