February 10, 2017

Clean Energy, Rain or Shine: The All-Weather Solar Cell

Kyle Miller, Solar Incentive Fellow

Scientists in Qindao, China have made an exciting clean energy breakthrough by designing a solar cell that can generate energy from raindrops! In the recently published edition of the Angewandte Chemie Journal, the Chinese scientists revealed the “all-weather” solar cell concept. This all-weather solar cell is still in early stages and needs more research, but it is an exciting new prospect for solar technology.

The unique component that makes this solar cell “all-weather” is liquid graphene. Graphene is a two-dimensional honeycomb lattice of carbon atoms that are bonded together. Like other structural modifications of carbon, graphene has some extraordinary properties like being stronger than steel and very stretchable, but most importantly, it efficiently conducts electricity.

Raindrops are made up of salts that contain positively-charged ions. The liquid graphene splits these positively-charged ions when they land on a solar cell, which consequentially generates electricity. The all-weather solar cell yields a solar-to-electric conversion efficiency of 6.35 percent, which is a considerable drop-off compared to the other solar cells in the market. However, the cell can generate hundreds of microvolts from raindrops.

One of the largest downsides to solar electricity technology is the intermittency of solar energy. On rainy days, solar cells do not produce at their standard efficiency because they struggle to capture diffuse light. However, a fully-developed all-weather solar cell would be able to compensate for those efficiency losses.

While all-weather solar cells are not yet ready to be competitive within the solar market, the potential to generate electricity from both the sun and raindrops is still quite exciting. Hopefully these Chinese scientists inspire further research on and exploration of all-weather solar cells and other innovative solar technologies!