Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (12): 2534-2542.doi: 10.3866/PKU.WHXB201310292

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

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).

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