Electric field effect on multi-anchoring molecular architectures: Electron transfer process and opto-electronic property

The molecular structures and optoelectronic properties of single/double-anchoring phenothiazine-based dyes (DCE1/DCE2) were calculated based on density functional theory (DFT) and time-dependent DFT (TD-DFT). There are two primary objectives: one is to study the influence of different number anchoring types on the overall efficiency, and the other is to shed light on how a local electric field affects the performance of double-anchoring dyes DCE2. The calculated results indicate that, DCE2 has larger harvesting efficiency (LHE), electron accepting power (ω⁺) and dipole moment (u_normal) as well as lower reorganization energy (λ_total) and chemical hardness (η), which lead to a higher short circuit current density (Jsc) and open-circuit voltage (Voc) compared to DCE1. Under a condition of electric field, the u_normal of DCE2 with the increase of electric field strength has increased as compared to nonelectric field environment, leading to a larger V_OC. Furthermore, the electron accepting power (ω⁺) is increased and the chemical hardness (η) is decreased, which will further improve the Jsc. Therefore, the results show that the electric field is beneficial to improve the performance of double-anchoring DCE2, and the electric field is an important way to further enhance efficiency of DSSCs.