Structural Engineering of π-Linker Aromaticity in Anthanthrene-Based Dyes with D–π–A Configuration: DFT Investigation to Enhance Charge Transfer in DSSCs

The development of efficient dyes for photon harvesting in dye-sensitized solar cells (DSSCs) is a critical area of research with the potential to enhance renewable energy technologies. This manuscript presents a novel approach to engineering dye structures (abbreviated as D2 dye features, an anthanthrene core with a resonance energy of ER = 694 kJ/mol and a reported power conversion efficiency (η) of 5.27%) by systematically replacing an anthanthrene core with various aromatic cores, aiming to understand the influence of resonance energy on molecular performance. By designing seven new dyes with resonance energies ranging from 255 to 529 kJ/mol, we conducted in-depth computational studies using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT) to explore the effects of π-aromatic linkers on their electronic properties. Our findings reveal key insights into intermolecular charge-transfer (ICT) mechanisms and how they relate to the resonance energy of dye cores, highlighting the significance of balanced charge mobilities in optimizing optoelectronic characteristics, as shown by the D9 dye with a naphthacene core.