Design, Synthesis and Photophysical Characterization of 9H-Fluorene Derivative-Based Organic Photosensitizers for...

A novel two metal-free organic photosensitizers have been synthesized and designed for DSSCs application. The impact of these organic dyes on the performance of the DSSC was thoroughly investigated. The synthesized organic dyes underwent characterization through FT-IR, NMR, UV-Vis spectra, and cyclic voltammetry techniques. The absorption spectra of FFA and FTA dyes exhibit notable absorption peaks at 668 and 572 nm. The analysis of electrochemical properties has been conducted through cyclic voltammetry. The FFA and FTA have demonstrated short-circuit current densities (J_SC) of 12.23 mA/cm² and 11.21 mA/ cm², respectively, with corresponding power conversion efficiencies (η) of 7.01% and 6.35%. Additionally, the optical band gaps for FFA and FTA were observed 1.83 eV and 2.13 eV. Furthermore, the geometrical and photophysical properties were calculated utilizing DFT and TD-DFT at the B3LYP/6-31G level of theory, followed by a comparison with experimental values. The experimental and calculated values clearly demonstrate that FFA and FTA dyes possess significant potential for efficient DSSC applications.