D–A−π–A System: Light Harvesting, Charge Transfer, and Molecular Designing

Abstract

Three organic dyes (XY1, XY2, and XY3), synthesized by inserting a thiophene heterocycle and shifting the position of benzothiadiazole (BTZ) auxiliary acceptor on the cyclopentadithiophene(CPDT) π-bridge, are theoretically investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT) for their potential applications in solar cells. The photoelectric paremeters (short-circuit current, open circuit voltage, conversion efficiency) are evaluated by the following factors: energy levels and the orbital compositions, the absorption spectra, NBO analysis from S0 to S1, the qualitative descriptions of DCT, Δr, S, and ΔQ for intramolecular charge transfer (ICT) processing, the adsorption energy (Eads), and the excited lifetime (t), the shift of CB and vertical dipole moment (μnormal), the electron injection lifetime (τ), the Marcus rate of inner-path recombination, the simulation of outer-path recombination dye···I2 and dye regeneration [dye+•I–], etc. The Eads, the excited lifetime (t) and the...