An interdisciplinary team has improved the performance of protein-based photovoltaic devices with a new kind of electrode.

Photosynthesis generates a remarkable 90 terawatts of power, with proteins such as photosystem I (PSI) having a central role in this process. The prospect that these proteins could be harnessed to generate electricity as a final product, rather than chemical energy, has motivated researchers to make them the active component of photovoltaic cells. Pursuing this goal, an interdisciplinary team at Vanderbilt University in Nashville, Tennessee has now attached PSI to nanoporous gold-leaf electrodes as part of an electrochemical photovoltaic cell (ACS Nano doi: 10.1021/nn800389k; 2009). The high surface-area of the modified electrodes allows for a greater density of proteins, which increases the photocurrent by a factor of three, compared with the same cell using planar electrodes.

The collaboration began through the Vanderbilt Institute for Nanoscale Science and Engineering (VINSE), which was set up to bring together faculty and students across the university. It was through VINSE that Kane Jennings, a professor in the department of chemical and biomolecular engineering, met David Cliffel, a chemistry professor and an expert on electrochemistry and electron transfer. Peter Ciesielski, the first author on the paper, is a graduate student in Vanderbilt's Interdisciplinary Materials Science Program.

Neither Jennings nor Cliffel had much of a biology background: “We both had to learn the biology, and we are still learning the biology.” admits Jennings. Nor was the development straightforward: “The error bars in biology are typically quite a bit larger than those in chemical engineering and chemistry. Approximately two years of work was required to obtain consistent properties from [the photosynthetic proteins]”. But it was worth it. “The accompanying infusion of new ideas is an exciting reprieve,” says Jennings, “because staying within one's comfort zone can become boring after a few years.”