Theoretical design and characterization of high-efficiency organic dyes with different electron-withdrawing groups based on C275 toward dye-sensitized solar cellsElectronic supplementary information (ESI) available. See DOI: 10.1039/c6nj01731b

• Main Authors: Li, Shuang-Bao, Gu, Dong-Mei, Zhang, Ji, Geng, Yun, Zhang, Min, Su, Zhong-Min
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c6nj01731b

Seven dyes 1-7 with different electron-withdrawing groups were designed and investigated based on C275 , which has been the most efficient metal-free donor/acceptor dye until now to screen outstanding dyes for an organic dye-sensitized solar cell (DSSC). Some basic parameters, such as geometries, electronic structures, absorption spectra and charge recombination, were investigated by DFT and TDDFT methods, and the theoretical maximum short-circuit current density ( J max sc ) and the electron injection lifetime ( τ ) were also calculated to estimate the light-harvesting abilities and electron injection efficiencies of these dyes, respectively, which adds some quantitative information for our study. Moreover, the charge recombination process was also discussed according to the distance ( r ) between the semiconductor surface and cation holes in the dye. The results show that all the dyes in our work exhibit ultrafast and effective electron injection with τ values in fs. Dyes 3 , 5 and 7 have better light-harvesting abilities and dyes 1 , 4 and 7 have better electron-collecting abilities with slower charge recombination than C275 . Thus, the designed dye 7 might have superior performance in comparison with C275 and could be the most promising candidate as an organic dye in DSSCs. The designed organic dye 7 with a naphthothiadiazole electron-withdrawing group will exhibit superior performance in comparison with C275 for dye-sensitized solar cells.