Characterization and Theoretical Insights Into Coumarin‐Based Sensitizers for Dye‐Sensitized Solar Cells

Density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations were employed to evaluate the potential of coumarin‐based dyes, 7‐diethylamino‐4‐methylcoumarin (DAMC), Coumarin 102 (C102), Coumarin 153 (C153), Coumarin 343 (C343), Coumarin 6 (C6), Coumarin 7 (C7), and Coumarin 30 (C30), as sensitizers for dye‐sensitized solar cells (DSSCs). Complementary experimental studies were performed to assess their photovoltaic performance. UV–vis absorption spectroscopy revealed the optical behavior of both isolated dyes and dye‐sensitized TiO 2 films, highlighting variations in light‐harvesting capabilities and adsorption strengths. C343 exhibited the most favorable photovoltaic response among the investigated dyes, enabling mechanistic correlations between molecular structure, light‐harvesting, charge‐transfer dynamics, and device performance. C343 displayed short‐circuit current density ( J SC ) of 1.12 mA cm −2 , an open‐circuit voltage ( V OC ) of 259 mV, and a fill factor (FF) of 40.