Theoretical study of metal-free organic dyes based on different configurations for efficient dye-sensitized solar cells

摘要

Considering different solar dyes configuration, four novel metal-free organic dyes based on phenoxazine as electron donor, thiophene and cyanovinylene linkers as the p-conjugation bridge and cyanoacrylic acid as electron acceptor were designed to optimize open circuit voltage and short circuit current parameters and theoretically inspected. Density functional theory and time-dependent density functional theory calculations were used to study frontier molecular orbital energy states of the dyes and their optical absorption spectra. The results indicated that D2-4 dyes can be suitable candidates as sensitizers for application in dye sensitized solar cells and among these three dyes, D3 showed a broader and more bathochromically shifted absorption band compared to the others. The dye also showed the highest molar extinction coefficient. This work suggests optimizing the configuration of metal-free organic dyes based on simple D-p-A configuration containing alkyl chain as substitution, starburst conformation, and symmetric double D-p-A chains would produce good photovoltaic properties.