Density functional theory characterization and verification of high-performance indoline dyes with D-A-π-A architecture for dye-sensitized solar cells

Six indoline-based dyes 1-6 used in DSSCs with difference in pi spacer were theoretically researched and verified using density functional theory (OFF) and time-dependent density functional theory (TD-DFT) to shed light on how the additional (auxiliary) acceptor and pi spacer order influence the performance of the dye. Key parameters associate with the short-circuit current density (J(sc)) and open-circuit photo-voltage (V-oc), including light-harvesting efficiency LHE, electron injection driving force Delta G(inject), total reorganization energy (total lambda(total) (lambda(n) and lambda(e)), the vertical dipole moment mu(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. (C) 2013 Elsevier Ltd. All rights reserved.