Porphyrins for efficient dye-sensitized solar cells covering the near-IR region

A series of new porphyrins (LWP1-4) for dye-sensitized solar cells (DSSCs) were prepared by attaching pyrene or a 4-dimethylaminophenyl group in combination with anthracene to modify the porphyrin core. Fundamental studies showed that incorporation of these moieties renders feasible tuning of spectral and redox properties of the porphyrins. Significantly, DSSCs adopting the LWP1 dye exhibit energy conversion up to 800 nm without compromising the overall efficiency. This achievement is attributed to the collective effects of the broadened and red-shifted IPCE spectra, elevated energy levels at the excited states of the dyes, suitable dye soaking processes, and suitable electron-donating substituents.