Molecular Design, DFT Study and Optoelectronics Properties of Several DSSCs Sensitizers Based on Different Donor Groups.

Dye-sensitized solar cells (DSSCs) are a type of high-efficiency solar cells that can absorb sunlight using a dye sensitizer positioned on top of a titanium dioxide layer. The sensitizer is the core component in DSSCs, and the photo-to-electric conversion efficiency of DSSCs can be significantly improved by optimizing the dye sensitizer structure and properties. In this paper, a set of D-A-π-A sensitizer (SHY1 ∼ 4) were designed by modifying different donor groups and analyzed their charge transfer and photophysical properties. We compared the geometric structure, frontier molecular orbitals, Uv-vis, charge density difference, transition density matrix, photovoltaic and quantum chemical parameters of several molecules by means of density-functional theory (DFT) and time-dependent density-functional theory (TD-DFT). The results showed that SHY-2 with 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline as the donor group possessed the most outstanding photophysical and photochemical properties, including the smallest frontier molecular orbitals energy gap, the wider UV-Vis spectral range, the most appropriate open-circuit voltage value and so on, which provided a theoretical basis for the subsequent design and synthesis of molecules.