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

Six indoline-based dyes 1a6 used in DSSCs with difference in pi 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 pi spacer order influence the performance of the dye. Key parameters associate with the short-circuit current density (Jsc) and open-circuit photovoltage (Voc), including light-harvesting efficiency LHE, electron injection driving force IGinject, total reorganization energy I>total (I>h and I>e), the vertical dipole moment mu normal, the energy differences eVoc between ELUMO and ECB as well as the extent of electron recombination were characterized. The theoretical results reveal that compared with dye 1, dyes 2a6 improve the performance potentially due to their auxiliary acceptor. These enable us to determine these factors related to the Jsc and Voc can be significantly influenced by the incorporated electron-withdrawing subunit into molecular backbone.