作者：S. X. Wei, X. Q. Lu,* X. F. Shi, Z. G. Deng, Y. Shao, L. M. Zhao, W. Y. Guo, C.-M. L. Wu
关键字：Theoretical insight,dye-sensitized solar cells
论文来源：期刊
具体来源：Int. J. Photoenergy
发表时间：2014年

The design of light-absorbent sensitizers with sustainable and environment-friendly material is one of the key issues for the future development of dye-sensitized solar cells (DSSCs). In this work, a series of organic sensitizers incorporating alkoxy-substituted triphenylamine (tpa) donors and binary π-conjugated bridges were investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT). Molecular geometry, electronic structure, and optical absorption spectra are analyzed in the gas phase, chloroform, and dimethylformamide (DMF) solutions. Our results show that properly choosing the heteroaromatic atoms and/or adding one more alkoxy-substituted tpa group can finely adjust the molecular orbital energy. The solvent effect renders the HOMO-LUMO gaps of the tpa-based sensitizers decrease in the sequence of DMF solution < chloroform solution < gas phase. The absorption spectra are assigned to the ligand-to-ligand charge transfer (LLCT) characteristics via transitions mainly from tpa, 3,4-ethylenedioxythiophene (edot), and alkyl-substituted dithienosilole (dts) groups to edot, dts, and cyanoacrylic acid groups. The binary π-conjugated bridges play different roles in balancing the electron transfer and recombination for the different tpa-based sensitizers. The protonation/deprotonation effect has great effect on the HOMO-LUMO gaps and thus has great influence on the bands at the long wavelength region, but little influence on the bands at the short wavelength region.Theoretical Insight into Organic Dyes Incorporating Triphenylamine-Based Donors and Binary π -Conjugated Bridges for Dye-Sensitized Solar Cells.