Light Harvesting "Quantum Photocells" Herald A New Age in Solar Energy

Quantum Physics Meets Photosynthesis

Science once again reaches a milestone in technology by modeling it after nature. Researchers have devised a new type of highly efficient photocell by studying photosynthesis in plants.

Nathan Gabor, assistant professor for physics and astronomy at the University of California, Riverside, led research spurred by a simple question as to why plants are green. This eventually led to a quest to mimic plants’ ability to efficiently harvest energy from the Sun regardless of how erratic the sunlight is.

Using his background in physics to solve the biological question, Gabor and his team devised a quantum heat engine photocell capable of regulating the conversion of energy, without the need for external control—it does so by itself, much like a plant does. Their study has been published in the journal Nano Letters.

Quantum heat engines (QHE) are mostly used in refrigerators and “are thermal machines where the working substance is a quantum object,” according to the American Physical Society. The team was able to apply the engine to modulate the energy flow to the cells.

In the process, the team discovered that absorbing green light did not yield any benefits in regulation of energy absorption, which could explain why green plants are so widely seen in nature.

Solar Cells Made Better

The main problem with current solar cells is that about 80 percent of the Sun’s energy is wasted. This is because solar cells have a limited capability to quickly adjust to fluctuations in sunlight—which happens within split seconds. The process required for existing solar cells to handle fluctuations in solar power involves a system of voltage converters and feedback controllers, making it difficult for them to keep up with energy fluctuations and resulting in wasted energy.

As the world makes the shift towards clean energy, a lot of research is being dedicated to finding the easiest, most efficient energy source with the least possible consequences to the environment. Sunlight is one of the most abundant sources there is and the ability to harvest it efficiently would drastically change how our energy needs are met.