Blackberries, blueberries, oranges, and grapes — they not only provide energy for you…someday they may provide energy for your home! Yep, for those of you who just didn’t think solar energy researchers were exploring all their options, well, you can knock one more off the list. Now, in experiments conducted by students at Rowan University in Glassboro, NJ, dyes from various fruits are being used to create solar cells.

Using a relatively new science called Biomimetics, these students are developing a “third generation” of solar cells. The already commercially available, crystalline silicon, photovoltaic cells, which you’ll see as panels on rooftops, are considered “first generation.” solar cells. Thin film solar cells are “second generation.” Both of these first two generations are efficient but also expensive. What these chemistry majors are attempting to do, through a process they developed themselves, is find an inexpensive, natural way to make functioning solar cells.

The researchers extract dye from a wide range of fruits and blend them. They separate heavy particles using filters and a centrifuge, producing a liquid, which they freeze dry. They are left with sugar and a dye. They then separate these two and are left with pure, brightly colored dyes.

Next, the dye is placed on a conductive glass coated with a film of titanium dioxide, a common material found in many consumer products including white paint, which bonds the dye to the glass. After adding iodine and potassium iodide for dye regeneration, the process is complete. When light hits the dye it excites the electrons, which then travel to a conductive glass electrode which, in turn, produced electricity.

As the students admit, there is much less output from these solar cells than their traditional silicon-based counterparts, but using a fruit dye is far cheaper. They even go so far as to claim that anyone could make a solar cell using their method. All they’d need is fruit, white paint, iodine, and glass.

Granted fruit dye solar cells are still very much in the research stage and still years from having any significant commercial use. And these “dye-sensitized solar cells” (originally invented by a Swiss chemist) are not alone in “third generation” solar cell development. But the common idea is to use inexpensive materials to create biomimetic structures that are man-made but imitate nature.

These Rowan university chemistry students just may be onto something. As part of a chemistry laboratory course, students will continue working to develop better dyes to harvest light and work to assemble larger aggregates of photosynthetic pigments using green plants and bacteria. And because of the success and innovation by this group of Rowan chemistry students, The Petroleum Research Fund of the American Chemical Society will fund future solar energy research at the university.

And who knows? Someday down the road we may just have commercially viable, organic solar cells.

Source: Using Fruit to Aid the Sun’s Work

Posted on June 2nd in Solar News by Dan.