DFT simulations of photovoltaic parameters of dye-sensitized solar cells with new efficient sensitizer of indolo[3, 2-b]carbazole complexes

Developing economical and high-performing sensitizers is crucial in advancing dye-sensitized solar cells (DSSCs) and optoelectronics. This research paper explores the potential of novel red light-absorbing organic dyes based on Indolo[3,2-b]carbazole (ICZ) as the donor applied in co-sensitizer-free DSSCs for breakthroughs in photovoltaic (PV) applications. DFT and TD-DFT based computational methods were employed to calculate the conduction band levels, electron injection capabilities, and power conversion efficiency (PCE) of metal-free organic dyes (ICZ1–ICZ9) having D-A-π-A architecture. Comprehensive analyses included NBO, DOS, FMO, ICT, MEP, binding energy, and TDM analysis. Quantum chemical calculations of the structural, photochemical, and electrochemical properties, as well as the key parameters, reveals that all the designed dyes could be an excellent candidate for high-efficiency DSSCs due the small energy gap (2.130–1.947 eV), longer wavelength absorption (759.47–520.63 nm), longer lifetimes (15.65–6.67 ns), a lower ΔG_reg (0.29–0.14 eV), a significant dipole moment changes (31.489–16.195D), LHE (0.95-0.46), the large q^CT (0.962–0.689), small D^CT (7.657, 4.897 Å), and V_OC (1.13–0.86 eV). This quantum simulation showed that, when compared to reference D8, the photovoltaic dyes ICZ8, ICZ2, and ICZ7 are recognized as being eye-catching. Furthermore, dye@(TiO₂)₉ cluster model results demonstrate promising prospects for enhancing the photovoltaic (PV) performance of ICZ1–ICZ9 dyes by electron injection and conduction band (CB) engineering. This study will help the experimentalists for developing ICZ-based PVs as more efficient and sustainable energy solutions.