Four physicists at the University of California, Riverside decided to blend photosynthesis and quantum physics to work towards greener solar cells. Plants effectively regulate energy flow from the sun, but since current affordable man-made solar cells hover around just 20 percent efficiency, the scientists decided to take cues from vegetation.
Current solar cells require feedback controllers and voltage converters to manage fluctuations in the amount of energy streaming from the sun, and end up wasting loads of energy. Their lack of efficiency is one hurdle standing in the way of mass adoption. But plants don’t need such hindering mechanisms. The UC Riverside team decided to reevaluate solar energy conversion in light of both photosynthesis’ efficiency and quantum physics principles.
The physicists created what UC Riverside calls a novel kind of quantum heat engine photocell, a device that assists in the sunshine-to-electricity conversion process. Their new photocell draws on two quantum mechanical photocell systems that absorb either one or two colors of light, allowing the photocell to alternate between absorbing light at high and low power. According to UC Riverside, this innovation could allow a photocell to “convert varying levels of solar power into a steady-state output.”
For UC Riverside assistant professor Nathan Gabor, who took part in the research, the journey to a better solar cell started in 2010 with the simple question, “Why are plants green?” He found out no one truly understands why, and decided to search for an answer. His quest, drawing on his physics background melded with deeper study into biology, may unlock the secrets to a more effective solar cell.
The journal Nano Letters published the physicists’ research online in November.