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Abstract: Six indoline-based dyes 1–6 used in DSSCs with difference in π spacer were theoretically researched and verified using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to shed light on how the additional (auxiliary) acceptor and π spacer order influence the performance of the dye. Key parameters associate with the short-circuit current density (J sc) and open-circuit photovoltage (V oc), including light-harvesting efficiency LHE, electron injection driving force ΔG inject, total reorganization energy λ total (λ h and λ e), the vertical dipole moment μ normal, the energy differences eV oc between E LUMO and E CB as well as the extent of electron recombination were characterized. The theoretical results reveal that compared with dye 1, dyes 2–6 improve the performance potentially due to their auxiliary acceptor. These enable us to determine these factors related to the J sc and V oc can be significantly influenced by the incorporated electron-withdrawing subunit into molecular backbone. [Copyright &y& Elsevier]

Abstract: Series sensitizers of indoline and triphenylamine as the donor group, quinoxaline and its derivatives as the additional acceptor, different heteroaromatic rings (furan, benzene and selenophene) as the π-conjugated group, 2-cyanoacrylic acid as the acceptor/anchoring which featured on the D–A–π–A architecture have been theoretically designed based on the reported dyes IQ2 and TQ2 used in dye-sensitized solar cells (DSSCs), to shed light on how the additional (auxiliary) acceptor and π spacer influence the performance of the dyes. These enable us to determine master factors influenced the efficiency of DSSCs, such as the light-harvesting efficiency, lifetime of excited state, exciton binding energy, total reorganization energy and electron injection driving force as well as the vertical dipole moment. The theoretical results revealed that compared with dye IQ2, our designed dyes IQS2 and IQS3 displayed much better light harvesting properties and longer first excited lifetime. [Copyright &y& Elsevier]