Thieno[2,3-b]indole-based organic dyes for dye-sensitized solar cells: Effect of π-linker on the performance of isolated dye and interface between dyes and TiO2

A series of novel D-pi-A type organic dyes with different pi-linker are theoretically designed and investigated for their potential applications in dye-sensitized solar cells (DSSCs). We mainly focused on the influence of the extension of pi-linker on the overall efficiency. The discussions are classified into two aspects: one is the isolated dyes and the other is the dye TiO2 system. The calculated results indicate that the isolated dyes THI-2T-C, THI-4T-3C, and THI-6T-5C have the better overall efficiency. Further, the THI-4T-3C and THI-5T-4C have the acceptable performance if the dye-TiO2 system is considered. Combination of the isolated and the adsorbed systems, the THI-4T-3C with the moderate pi-linker is considered to be more suitable choice for thieno[2,3-blindole-based dyes rather than the longest pi-linker. (C) 2016 Elsevier B.V. All rights reserved.