Derivatized photosensitizer for an improved performance of the dye-sensitized solar cell

In recent years, Dye-Sensitized Solar Cell (DSSC) has drawn enormous attention due to its advantages over conventional silicon solar cells in terms of technological, financial, and environmental sustainability. In this work, experimental and computational methods were employed to investigate the effect of derivatization of dyes-cyanoacetic acid derivatives of cinnamaldehyde (HB1) photosensitizers on the performance of the TiO2based DSSCs. The optical properties and the functional groups of the two dyes were determined by using UV-vis spectrophotometer and FT-IR spectroscopy, respectively. The J-V characterization and power-conversion efficiency of dyes in TiO2-based DSSCs containing I-/I3- electrolyte, and Graphite-carbon based FTO-glass (counter electrode) were examined. The study revealed that the HB1 (derivatized dye) was shown to improve the DSSC performance compared to cinnamic acid (underivatized dye). The HOMO-LUMO energy bandgap was estimated using the density functional theory density (DFT) tool as implemented in Gaussian09 software with a basis set of B3LYP/6-31G (d, p) level of theory. The bandgap of dyes before and after derivatization were found to be 4.93 and 3.73 eV, respectively, higher than the bandgap of TiO2 (3.2 eV). HB1 offers the highest VOC, JSC, fill factor (% FF), and power-conversion efficiency of 0.48 V, 0.19 mA/cm2, 0.61, and 0.50 %, respectively. The study found that the derivatization technique greatly improved the conversion efficiency of the DSSCs by about 22 % in comparison to the cinnamic acid dye (0.39 %).