Push-Pull N-Annulated Perylene-Based Sensitizers for Dye-Sensitized Solar Cells: Theoretical Property Tuning by DFT/TDDFT

Abstract

© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim We evaluate the effects of donor and π-linker moieties on power-conversion efficiency for a series of push-pull type, N-annulated perylene dyes for dye-sensitized solar cells. Triphenylamine and diphenylamine are used as electron donors. We investigate the structural, optical, and electronic properties of dyes by performing density functional theory (DFT) calculations at the B3LYP level, using the 6-311G(d,p) basis set. Electronic absorption wavelengths were investigated using time dependent DFT (TD-DFT) calculations on M062x/6-311G(d,p) in THF. Our calculated results reveal that the diphenylamine (DPA) donor provides a small dihedral angle between diphenylamine and the perylene core, resulting in a red-shifted absorption spectrum. Introduction of an O-methoxy substituent into diphenylamine improves its donor properties, red-shifts the absorption wavelength, and increases the dipole moment, indicating increased intramolecular charge transfer in the O-methoxy substituted dye. Incorporation of a C-C triple bond in linker extends the π-conjugation system and decreases the dihedral angle between N-annulated perylene and cyanoacrylic acid; the dye adopts a planar structure, causing a red-shift in the absorption spectrum. Our results demonstrate that use of computational design can to help the experimentalist for out looking future developments to identify push-pull perylene sensitizers for highly efficient solar cells.