God, Hope & Helping Others
A scientist at Wake Forest University has found a way to replace expensive elements of solar panels with berries from the common pokeweed. Success on a commercial scale could be the key to supplying cheap, renewable energy to the developing world.
As people continue to realize the dirty and finite nature of fossil fuels, the quest for affordable-yet-renewable energy has picked up speed. The need for reliable sources of clean electricity is especially acute in the developing world, where coal and natural gas plants are springing up at an alarming rate.
Solar power presents a unique opportunity for impoverished nations to leap-frog the fossil fuel era, skipping decades of pollution, and allowing them to establish the smarter grid that so many developed countries are struggling to implement. There’s just one problem: solar technologies are still just too costly to utilize on a large scale.
While brainstorming ways to overcome this roadblock, David Carroll, director of the Center for Nanotechnology and Molecular Materials at Wake Forest, was inspired by the flashy red berries of the pokeweed growing near his house.
Carroll and his team realized that natural dyes from plants rich in compounds called flavonoids can produce electrical current when sandwiched between the layers of a solar cell, in the spot where silicon would normally go. Pokeweed is a hardy plant that produces dark red berries that are not traditionally eaten.
To test its conductivity, the team smashed up the raw pokeberries and painted the purple juice on a transparent conductor, a piece of glass or plastic with an aluminum zinc oxide coating. That was sandwiched against a second plate covered with a very thin metal coating with a dilute solution of iodine between and placed in the sun.
Carroll and the students soon saw the results: poke power. They produced their first test pieces last summer.”A large panel of this stuff, a couple of meters on each side, could produce 5 to 10 watts pretty easily. That’s going to charge a battery up pretty fast,” Carroll said.To be sure, that’s a very low-power solar panel – creating enough power to run a small light bulb through the night, perhaps. But that low efficiency is just the point, Carroll said.
In many developing countries, work, study, and play time is dictated by the availability of light. Often remote villages depend on kerosene lamps to provide light after sundown, but these are dangerous and heavily pollute the air inside a home. With low-cost solar panels powered by pokeweed, families could enjoy clean electric light and perhaps enough power for a radio or cell phone that would drastically improve their quality of life.
Source: News Observer