Everyone has seen solar panels producing energy from sun's sunlight. They may work very efficiently when it is a bright sunny day. But what if it is cloudy and rainy?

Scientists in China have developed a way for solar panels that produces energy from rain drops. This experiment was demonstrated in a laboratory at Soochow University in China. The scientists have coated the bottom side of the solar cell with a thin layer of graphene which interacts with the positively charged ions found in the rain drops.

Rain is an excellent reservoir of dissolved salts full of positive and negative ions. When rain drops hit the graphene layer it forms a pseudo capacitor and positive ions like ammonium, calcium and sodium stimulate electric currents. An atom thick layer of graphene can generate hundreds of mill volts worth of voltage, and on sunny days, the same cells have efficiency of up to 6.53 percent efficiency under simulated sunlight. The new design could be applied to many different solar cell designs and the researchers believe it can guide the design of advanced all weather solar cells.