On days when it rains or there is a lot of cloud cover, there is only so much energy that panels can store for later use. Engineers and material scientists have been able to make cell efficiency better over the years, with solar panels that can still store some energy when sun is not out.
Now, thanks to a thin layer of graphene coating the solar cells developed by the scientists from Yingkou OPV Tech New Energy can create electricity from rain drops. Graphene is known for its conductivity, among many other benefits, and the one-atom thick graphene layer can allows electrons to move across the surface of the cell. In situations where water is present, graphene binds its electrons with positively charged ions. A process called the Lewis acid-base interaction.
The water adheres to the graphene, forming a dual layer, or pseudocapacitor, with the graphene electrons. The energy difference between these layers is so strong that it generates electricity.
These new solar cells are said to yield an optimal energy conversion efficiency of 6.53 % under 1.5 atmosphere thickness irradiation and current over µA, along with a voltage of hundreds of mV by simulated raindrops.
