The structure-photovoltaic property relationship of arylamine-modified ruthenium polypyridyl sensitizers in dye-sensitized solar cell: probed by DFT and TD-DFT

Abstract

Dyes play multiple roles in dye-sensitized solar cells (DSSCs); however, the rational design of efficient dyes is highly challenging due to the sophisticated optoelectronics physics and electrochemistry phenomena. In this work, Ru (II) complexes modified by arylamine groups were used to study the structure-performance relationship. Density functional theory (DFT) and time-dependent DFT methods were employed to calculate the geometries, electronic structures, and optical properties of dyes, while quantum dynamic simulation was conducted to study the interfacial electron transfer (IET) in dye/TiO₂ combined systems. The calculated results suggest that dyes with electron-donating N,N-dibenzyl-aniline and piperidine-modified arylamine groups induce effective intermolecular charge transfer, quickening the IET rate and elevating the TiO₂ conduction band (CB) edge, thus augmenting short-circuit current (J_sc) and open-circuit voltage (V_oc). The N-phenylcarbazol ligand is not suitable for modifying dyes due to weak interfacial electron coupling and invalid IET rate. The simulation highlights the potential of structurally modified Ru-dyes with N,N-dibenzyl-aniline and piperidine ligands, and provides a method for designing and screening high-performance DSSC dyes.