Biohybrid Solar Cell Based On Spinach Delivers Optimum Electrical Power

This is a biohybrid solar cell that uses the photosynthetic protein from spinach made by Vanderbilt students based on a previous design.
Credit: Amrutur Anilkumar, Vanderbilt University

A biohybrid device is a device that utilizes biological components such as cells and tissues to carry out certain functions or capabilities. Biohybrid devices are usually found in the medical field especially in organ transplant technology. But now, a group of researchers have adopted this technology and used it to produce a biohybrid solar cell.

A solar cell is a solid state electrical device that converts light energy into electrical energy. Sunlight is converted into direct current electricity. This is done through the photovoltaic effect (using light to convert to energy) using semiconductors grouped into solar panels.

These solar panels made up of a group of solar cells containing a photovoltaic material which is usually silicon based. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide.

The combination of biohybrid technology and solar cell technology is also called organic photovoltaics.

Spinach power gets a big boost

An interdisciplinary team of researchers at Vanderbilt University have developed a way to combine the photosynthetic protein that converts light into electrochemical energy in spinach with silicon, the material used in solar cells, in a fashion that produces substantially more electrical current than has been reported by previous "biohybrid" solar cells.

The research was reported online on Sep. 4 in the journal Advanced Materials and Vanderbilt has applied for a patent on the combination.

"This combination produces current levels almost 1,000 times higher than we were able to achieve by depositing the protein on various types of metals. It also produces a modest increase in voltage," said David Cliffel, associate professor of chemistry, who collaborated on the project with Kane Jennings, professor of chemical and biomolecular engineering. "If we can continue on our current trajectory of increasing voltage and current levels, we could reach the range of mature solar conversion technologies in three years."

The researchers' next step is to build a functioning PS1-silicon solar cell using this new design. Jennings has an Environmental Protection Agency award that will allow a group of undergraduate engineering students to build the prototype. The students won the award at the National Sustainable Design Expo in April based on a solar panel that they had created using a two-year old design. With the new design, Jennings estimates that a two-foot panel could put out at least 100 milliamps at one volt – enough to power a number of different types of small electrical devices.