American researchers have developed graphene-based solar cells that generate electricity from rain as well as sunlight

 

American researchers have developed graphene-based solar cells that generate electricity from rain as well as sunlight — clean power from precipitation that covers the sky when solar panels need it most.

The concept of generating electricity from raindrops has been attempted through piezoelectric, triboelectric, and electrochemical mechanisms for over a decade without producing a commercially viable device. Graphene — the single-atom-thick carbon structure whose extraordinary electrical properties have made it one of the most studied materials of the 21st century — provides the enabling material whose unique electrochemical properties make rain-electricity generation practically viable for the first time.

When raindrops contact a graphene surface, the dissolved ions in rainwater — ammonium, calcium, sodium, and chloride — adsorb preferentially to the graphene surface, creating a charge double layer at the graphene-water interface whose formation and collapse generates a measurable electrical current. Researchers at the University of Texas at Austin's Center for Electrochemistry have fabricated a graphene film over a conventional silicon solar cell, creating a bifunctional device that generates electricity from photovoltaic effect under sunlight and from the electrochemical double-layer effect under rain simultaneously.

Outdoor testing of the dual-mode graphene-silicon solar cells in Austin — a city with significant rainfall during its spring and autumn wet seasons — demonstrated electricity generation during every measurable rain event throughout a 12-month test period, with peak rain-electricity output of 8 milliwatts per square metre during heavy downpours. When integrated over the annual cycle, the graphene layer adds approximately 5% additional electricity generation from rain events compared to the solar-only baseline.

America made a solar panel that works in the rain. The weather is no longer the enemy.

Source: University of Texas at Austin Center for Electrochemistry & US Department of Energy, 2024

#EnergyInnovation #RainSolar #USAEnergy #CleanEnergy