物理化学学报 >> 2010, Vol. 26 >> Issue (05): 1408-1416.doi: 10.3866/PKU.WHXB20100518

量子化学及计算化学 上一篇    下一篇

用于染料敏化太阳能电池的D5同类物分子设计

詹卫伸, 潘石, 李源作, 陈茂笃   

  1. 大连理工大学物理与光电工程学院, 近场光学与纳米技术研究所, 辽宁 大连 116023
  • 收稿日期:2009-11-24 修回日期:2010-02-02 发布日期:2010-04-29
  • 通讯作者: 潘石 E-mail:span@dlut.edu.cn

Molecular Design of D5 Analogues for Dye-Sensitized Solar Cells

ZHAN Wei-Shen, PAN Shi, LI Yuan-Zuo, CHEN Mao-Du   

  1. Institute of Near-Field Optics and Nanotechnology, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023, Liaoning Province, P. R. China
  • Received:2009-11-24 Revised:2010-02-02 Published:2010-04-29
  • Contact: PAN Shi E-mail:span@dlut.edu.cn

摘要:

使用密度泛函理论(DFT)和含时密度泛函理论(TDDFT)以及自然键轨道(NBO)分析, 设计比有机染料D5更优秀的用于染料敏化太阳能电池(DSSC)的D5同类物分子. 在D5骨架的给电子基团上对称地引入给电子基(—OH,—NH2, —OCH3), 既可以使分子的最低未占据分子轨道(LUMO)能级提高, 又可以使吸收光谱红移, 从而既提高染料分子捕获太阳辐射光子的能力, 又提高由染料分子的激发态向TiO2电极注入电子的驱动力. 在D5分子的骨架上, 对称地引入受电子基(—CF3, —F, —CN), 可以使染料分子的吸收光谱强烈地红移, 从而更有效地利用太阳能. 由LUMO能级的提高和吸收光谱的红移来考虑, 所设计的D516, D536, D537分子是比D5优秀的同类物分子, 其中D516是最好的. 单从吸收光谱红移来考虑, 所设计的D565, D567, D568分子是比D5优秀的同类物分子, 其中D565 的吸收光谱有望与太阳辐射光谱更好地匹配. 挑选出来的这6种D5同类物分子都是D-π-A(电子给体-共轭π桥-电子受体)结构. 这几种分子的光激发引起的最高占据分子轨道(HOMOs)到LUMOs的跃迁是π-π*跃迁, 是分子内电荷转移, 吸收光谱是电子吸收光谱, 位于近紫外-可见光区. D516和D565有望成为比D5更优秀的用于DSSC的非金属有机染料分子.

关键词: 密度泛函理论, 染料敏化太阳能电池, 染料D5, 分子设计

Abstract:

Using density functional theory, time-dependent density functional theory and natural bond orbital analysis, we designed D5 analogue molecules, which are superior to the organic dye D5 for use in dye-sensitized solar cells. The symmetric introduction of the electron donating substituents (—OH,—NH2,—OCH3) to the electron donating groups of the D5 skeleton raises the energy level of the lowest unoccupied molecular orbital (LUMO) and causes a red-shift in the absorption spectra. These changes enhance the ability of the dye molecules to capture photons from solar radiation as well improving the driving force for electron injection from the dye molecule's excited state to the TiO2 electrode. The symmetric introduction of electron-acceptors (—CF3,—F,—CN) to the skeleton of D5molecules red-shifts the absorption spectra of the dye molecules greatly, allowing for more efficient use of solar energy. Considering the increase in the LUMO energy level and the red-shift in the absorption spectra, the designed molecules D516, D536 and D537 are superior analogue molecules of D5, of which D516 is the best. By only considering the absorption spectra red-shift, the designed molecules D565, D567 and D568 are superior analogue molecules of D5. Among these, the absorption spectrum of D565 is expected to better match the solar radiation spectrum. The six selected D5 analogues all have D-π-A (donor-conjugate π bridge-acceptor) structures. For these molecules, the transitions from the highest occupied molecular orbital to the LUMO arising from optical excitation are all π-π* intramolecular charge transfer transitions. Their electronic absorption spectra lie in the near-ultraviolet-visible light zone. Compared with D5, D516 and D565 are more applicable for use in DSSC as metal-free organic dye molecules.

Key words: Density functional theory, Dye-sensitized solar cell, Dye D5, Molecular design

MSC2000: 

  • O641