New pyran-based dyes as efficient sensitizers of p -type dye-sensitized solar cells

The application of four pyran based dyes as sensitizers for p-type dye-sensitized solar cells (p-DSCs) is here proposed. The dyes differ for the nature of the electron acceptor group which functionalizes the pyran core. Such a structural variation significantly influences the optical properties of the dyes so that the new pyrans overall cover most of the visible spectrum. In some cases, the p-DSCs employing these pyran-based dyes display power conversion efficiency significantly higher than the device sensitized with sensitizer benchmark P1. The relevant photo-electrochemical activity of one of the reported dyes combined with its ability to absorb the visible radiation in the lower energy portion (λ > 500 nm) makes it a promising candidate to be used in a tandem DSC (t- DSC) with the photoanode sensitized by a dye typically absorbing the higher energy zone of the visible spectrum (λ < 500 nm).