New dyes to benefit solar electricity and hydrogen fuel production

Researchers have made a two-fold breakthrough in advancing renewable energies with the development of a light sensitive dye which transfers electrons more efficiently than conventional technologies. The new dyes stand to be used in solar electricity generation and in creating hydrogen fuel, which in the past has proven expensive and energy hungry.

The chalcogenorhodamine dyes have been pioneered by chemists at the University of Buffalo (UB) along with their partners at the University of Rochester (UR). As sunlight strikes the dyes electrons are released allowing these available electrons to be used in one of two ways. In the solar cell application, where the dye can be used as part of a conventional dye-sensitive solar cells (DSSC), the newly freed electrons are able to travel through the solar cell, forming an electrical current. This is much like existing technology but offers greater efficiency.

In their application for producing hydrogen the process begins the same way, with sunlight knocking electrons from their atomic orbit. Freed electrons are then directed into a catalyst, where they drive a chemical reaction that splits water into hydrogen and oxygen. In laboratory tests it has been shown that these chalcogenorhodamine systems produce hydrogen at unprecedented rates. This is because the dyes absorb light more intensely than conventional dyes, and because they are able to transfer electrons more efficiently. The researchers found that chalcogenorhodamines work in both homogenous hydrogen production systems that employ cobalt as the catalyst, as well as in heterogeneous systems that employ platinum deposited on titanium dioxide as the catalyst.

The research team, led by UB Professor Michael Detty and UR Professor Richard Eisenberg, reported some of their findings in the Journal of the American Chemical Society in October 2010. A patent has been taken out covering the composition of the dyes. A separate patent application seeks to protect the dyes' use in hydrogen evolution and lists Detty and Eisenberg, along with Brandon Calitree, Alexandra Orchard and Theresa McCormick, as co-inventors of the process.