Novel Fullerene-Based Dyes for Solar Cells Applications: Insights from Density Functional Theory and Time Dependent Density Functional Theory Investigations

Abstract

Fullerene-based organic dyes hold significant promise for advancing solar cell technologies due to their exceptional optoelectronic properties. This study investigates two novel fullerene-based dyes, Fullerene Dye 1 and Fullerene Dye 2 (FD1 and FD2), using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) to evaluate their potential for solar cell applications. The electronic properties, including the Highest Occupied Molecular Orbital (HOMO), Lowest Unoccupied Molecular Orbital (LUMO), and HOMO-LUMO (H-L) energy gaps, were analyzed using the B3LYP functional with a 6-31G basis set, incorporating solvation effects with dichloromethane (DCM) in the Polarizable Continuum Model (PCM). FD1 exhibited a HOMO of -5.123 eV, a LUMO of -3.458 eV, and an H-L gap of 1.665 eV, while FD2 showed a slightly larger gap of 1.807 eV with a HOMO of -5.261 eV and a LUMO of -3.454 eV. Time-dependent DFT analysis revealed maximum absorption wavelengths (\lambda max) of 997.10 nm and 995.16 nm for FD1 and FD2, respectively, with corresponding oscillator strengths of 0.0075 and 0.0048. The light-harvesting efficiencies, LHEs of FD1 and FD2 were 0.018 and 0.012, respectively. Both dyes demonstrated favorable reorganization energy, \lambda=0.15eV, driving force for charge injection, \Delta G_inj = 0.542eV for FD1 and 0.546 eV for FD2, and low driving force for charge recombination (\Delta G_CR), indicating strong potential for efficient charge separation. These findings provide valuable insights into the electronic, optical, and charge transfer properties of fullerene-based dyes, with FD1 exhibiting a more balanced performance. The study highlights the potential of these dyes for enhancing the efficiencies of organic, dye-sensitized solar cells (DSSCs) and provides a foundation for future experimental validation and optimization.