Comparative Study of Electronic Structure and Photophysical Properties of Some New Lawsone Dyes in Dye-Sensitized Solar Cells by DFT and TD-DFT

This work aims to calculate the molecular structure, electrical, and photophysical properties of two types of Lawsone dyes using density functional theory (DFT) and time-dependent density functional theory (TDDFT) at the B3LYP/6-31++G** level of theory. The primary investigation focuses on the E and Z isomers of Lawsoneenaminone compounds, while the secondary investigation examines the ortho, meta, and para isomers of aminomethylnaphthaquinone compounds. The properties of the dyes in acetonitrile and water solvents were calculated using conductor-like polarizable continuum model (CPCM) methods. The analysis of the frontier molecular orbitals (FMOs) and the photovoltaic characteristics indicated that the E isomer of the Lawsoneenaminone dye, featuring a methyl group substitution, and the ortho geometric isomer of the aminomethylnaphthaquinone dye emerge as the most suitable dyes for use in DSSCs and all studied dyes exhibiting notable intramolecular charge transfer (ICT) capabilities. The optoelectronic properties of the Lawsoneenaminone dye suggest it is a more promising candidate for DSSC applications compared to the aminomethylnaphthaquinone dye. These findings hold promise for manufacturers of dye-sensitized solar cells who aim to synthesize Lawsone dyes with optimized optical and electronic properties.