Earlier this year I had the opportunity to do an interview with the discover of dye-sensitized solar cells (DSSCs), Michael Grätzel, in which he indicated that we should expect to see DSSCs capable of 10% conversion efficiency mass produced quite soon.
This is pretty impressive since Sony only demonstrated a module capable of 10% conversion efficiency in 2010.
But, according to some researchers a the Chinese Academy of Sciences, reaching this high conversion efficiency comes with the high price tag of needing resource-limited materials such as ruthenium. So the researchers, led by Yu Bai, have developed a method by which they can attain those efficiency levels with DSSCs without the use of ruthenium.
The research, which was published in the journal of the American Chemical Society, used an all-organic dye that can be used with cobalt in the place of the ruthenium.
To replace the use of ruthenium dyes researchers have been experimenting with so-called ‘push-pull’ dye sensitizers, which are molecules that contain “electron-accepting and –donating groups linked together by a conjugated bridge.”
The researchers took the push-pull dye sensitizers that had been tried thus far and incorporated an aromatic–sulfur bridging group. What resulted was a push-pull dye that reached an energy conversion efficiency of 9.4%, breaking the record for ruthenium-free DSCs just slightly behind the best ruthenium-based systems.
If this method can be incorporated into the mass production of DSSCs, it's likely the economics of this alternative solar cell could become even more attractive.