As our loyal readers already know, Michael Grätzel invented dye-sensitized solar cells 20 years ago, but, despite their low price, these organic cells have proved rather inefficient. However, Grätzel now found a solution for the cells to be cheaper and more efficient.
Grätzel’s cells use organic dyes to absorb sunlight, which hits the titanium dioxide nanoparticles in the cell, that are just below the dye, releasing electrons.
Lots of roadblocks went ahead of using this technology. One of the biggest was the moment that the researchers discovered that the dyes they used to attract sunlight contained ruthenium atoms, an expensive metal. Grätzel and his team, however, found an alternative to the expensive ruthenium.
They used complex three-part molecules consisting of a group that readily loses electrons, a group that readily accepts them, and a bridging unit containing a light-absorbing group related to that in chlorophyll.
This modification, along with another that refers to changing a voltage that had been responsible for the low voltage of these cells, will give future organic solar cells an efficiency of up to 12 percent and a voltage of 0.97V, making them to soon compete with silicon solar cells.
A future improvement to these solar cells will be the cells’ lifetime, since the materials currently used don’t last for long in harsh sunny conditions.