Iron-based photosensitizers to replace rare metals in solar energy applications

Unmet Need

Unlike traditional solar cells composed of crystalline silicone, a new solar technology known as dye-sensitized solar cells (DSSCs), can be manufactured using roll-to-roll printing on transparent and flexible materials, thus providing a low-cost alternative for shorter lifetime requiring applications. This not only lowers the cost of solar cell production and installation, but also enables new applications such as photovoltaic building facades, lightweight solar canopies, and solar integrated into consumer goods and electronics. Currently, however, DSSCs require expensive, rare, and toxic elements like ruthenium to support the energy conversion. This severely limits the potential scale of production of DSSCs.


Duke inventors have reported a photosensitizer meant to be used in dye-sensitized solar cells. Specifically, this is an iron-based complex in the form FeNHCPZn. The inventors engineered supermolecular Fe(II) chromophores based on the bis(tridentate-ligand)metal(II)-ethyne-(porphinato)zinc(II) conjugated framework, previously shown to give rise to highly delocalized low-lying 3MLCT states for other Group VIII metals (Ru, Os) complexes used in DSSCs. The technology was demonstrated in the lab as a photosensitizer in a proof-of-principle DSSC architecture.


  • A low-cost, air-stable replacement for heavy metals in dye-sensitized solar cells
  • More environmentally friendly
  • Could expand the advantages of DSSCs and open up new markets for solar energy