Investigating the Performance of Newly Designed Benzothiophene-4,8-Dione-Based Dyes for Dye-Sensitized Solar Cells

This research analyzes newly designed benzo1,2-b:4,5-b'dithiophene-4,8-dione-based electron–hole transport dyes (BDD1-BDD5), focusing mainly on their electronic and photovoltaic parameters. The calculations are performed using density functional theory with the M-06X/6-31G+(d,p) level of theory. Their highest occupied molecular orbital energies (E_HOMO) range from −5.46 to −2.58 eV, while their lowest occupied molecular orbital energies (E_LUMO) to range from −0.32 to −1.31 eV, with energy gaps (E_gaps) of 2.67 to −5.88 eV. Their photovoltaic parameters show light harvesting efficiency (LHE) ranging from 0.84 to 0.93 eV, open-circuit voltage (V_oc) ranging from 0.88 to 1.45 eV, fill factor (FF) ranging from 0.883 to 0.9117, short-circuit current (J_sc) ranging from 29.22 to 37.71 mA cm⁻², and maximum incident power (P_max) ranging from 24.01 to 39.92 W with maximum absorbance (λ_max) ranging from 390 to 557 nm. Their range of global chemical reactivity parameters, such as ionization potential (IP, 2.58–5.46 eV), electron affinity (EA, −0.25–0.32 eV), electronegativity (x, 1.25–2.61 eV), global hardness (η, 1.33–2.94 eV), electrophilicity index (0.17–0.38 eV), and softness (σ, 0.18–0.45 eV), provides insights into the stability, reactivity, electron transfer capabilities, and planarity of molecules. Their natural bond orbital analysis reveals transitions with perturbation energies ranging from 0.34 to 30.85 K cal mol⁻¹. These findings provide valuable insights into their properties and potential applications, particularly in photovoltaics as organic dyes.