Optimizing DSSC dyes: investigating synergistic interactions of chlorophyll b and anthocyanin with TiO2 through TD-DFT methodology

Abstract

Renewable energy research has focused extensively on dye-sensitized solar cells (DSSCs) as low cost, eco-efficient devices with promising photoelectrical conversion efficiency. This paper explores various natural dyes in DSSCs, showcasing their viability and efficiencies. The electronic and optical properties of chlorophyll b and anthocyanin under varying pH conditions are investigated using density functional theory (DFT) and time-dependent DFT. By analyzing dye–TiO₂ interactions, including molecular electrostatic potentials and Frontier molecular orbitals, the key factors influencing charge transfer and light harvesting efficiency are examined. The impact of co-sensitization and pH variations on DSSC performance is investigated. Specifically, the research explores the electrostatic potential, Frontier molecular orbitals, and absorption spectra of natural dyes anchored to titanium dioxide (TiO₂) surfaces. The results show that acidification and co-sensitization strategies, particularly with anthocyanin/chlorophyll combinations, along with insights into dye–iodine interactions, significantly enhance DSSC performance. These results provide valuable insights into the crucial role of pH, dye–dye interactions, and dye–TiO₂ interactions in optimizing DSSC efficiency. The investigation aims to identify optimal dyes for enhanced DSSC performance by considering molecular interactions, charge transfer, and electronic structure. Anthocyanin/chlorophyll complexes under acidic conditions exhibit markedly enhanced efficacy.