This study explores the potential of six novel metal-free organic dyes with a D- \(\pi\) -A architecture for use in dye-sensitized solar cells (DSSCs). All dyes share a common diethylamino coumarin donor and benzothiazole \(\pi\) -spacer, but differ in their acceptor/anchoring groups: acetic acid (A1), benzoic acid (A2), 2-cyanoacrylic acid (A3), rhodanine-3-acetic acid (A4), (chlorotetrahydroquinolinyl)cyanoacrylic acid (A5), and (oxotetrahydroquinolinyl)cyanoacrylic acid (A6). Using density functional theory (DFT) and time-dependent DFT (TD-DFT) with the B3LYP-D3 functional and 6-31G(d,p) basis set, we investigated the dyes’ photophysical and photoelectrochemical properties. The investigation focused on tailoring the molecular structure to enhance acceptor strength and evaluating the ease of adsorption onto TiO \(_2\) . Geometric, structural, electrical, and optical properties, along with charge transfer processes, have been analyzed using quantum chemical methods. The results suggest that these dyes are promising candidates for optoelectronic device applications.
