Exploring the impact of spacers in novel indole-based D–π–D–A dyes for high-efficiency DSSCs: A DFT/TD-DFT stud

Population growth and economic development have led to an increase in global energy consumption. Solar energy, a major renewable source, is essential to meeting human energy needs. This study, four new organic dyes (A1–A4) with a D–π–D–A structure using DFT and TD-DFT techniques for their potential application in dye-sensitized solar cells (DSSCs). The impact of π-bridge modifications of the A0 (reference molecule) on the structural, photovoltaic, optical and electronic properties was analyzed. The dyes showed band gaps (Egap) ranging from 2.4 to 3.5eV and absorption wavelengths (λ) from 420.16 to 627.4nm. Results suggest that the modification of the π-bridge of dye A0 enhanced intramolecular charge transfer (ICT). and improved hole injection. Theoretical open-circuit voltages (Voc) varied between 1.15 and 2.36 eV, while light harvesting efficiency (LHE) values ranged from 0.80 to 0.93. This study could effectively assist chemists in the synthesis of efficient dyes for DSSCs.