Theoretical study of the photovoltaic properties of dye-sensitized solar cells with novel D-A-π-A-type benzothiazole molecules as auxiliary acceptors

Abstract

The design and synthesis of low-cost-efficient sensitizer dyes is the most important approach to extend the application of dye-sensitized solar cells (DSSCs). Based on density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches, a series of D-A-π-A-type dye molecules with different auxiliary acceptors were designed. The structures, frontier molecular orbital (FMO), absorption spectra (UV) are investigated theoretically. Key parameters related to short-circuit current density and open-circuit voltage, such as light-harvesting efficiency (LHE), the reorganization energies (λ), the electronic injection-free energy (ΔG_inject), and the regeneration driving forces(ΔGreg)., are calculated individually. In addition, intramolecular charge transfer (ICT) properties such as charge transfer distance (D_CT) and dipole moment change (μ_CT) were investigated. Compared with other dyes, A-7 and A-9 dyes show outstanding performance. The purpose of our study is expected to provide a promising way to design possible candidate sensitizers for DSSC.