The Ruthenium Metal Complexes and Their Applications as a Light-Absorbing Material/ A DFT Study

We have developed new derivatives of Ruthenium metal complex-based dyes for use as sensitizers in DSSCs. Theoretical investigations have been conducted on ten Ruthenium metal complex clusters to analyse their geometries, electronic structures, density of states, optical properties, photovoltaic properties, and electrochemical properties. These investigations were carried out using the Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods. The objective was to design novel ligands that enhance the performance of dyes in dye-sensitized solar cells. We evaluated the impact of various chalcogen atoms in the ligand donor moieties, using different aromatic annulenes as building blocks. Additionally, we examined the influence of different functional groups connected to the bipyridyl unit in the ligand acceptor moiety. The designed dyes exhibit red-shifted spectra and improved electron transition abilities compared to other dyes, resulting in more effective intramolecular charge transfer upon photo-excitation. This suggests that these dyes would deliver the best photovoltaic performance. Furthermore, the designed dyes demonstrate a significantly enhanced light-harvesting efficiency, a higher open-circuit voltage (\({\text{V}}_{\text{o}\text{c}}\)), a greater short-circuit current, and favourable electrochemical properties. These characteristics are crucial for achieving faster electron injection efficiency and higher performance in photovoltaic devices.