A new type of solar cell can convert liquid water into clean hydrogen fuel 10 times more effectively than any other technology, and uses 10,000 times less precious material in the process. Invented by researchers in the Netherlands, the secret to these new prototype solar cells are gallium phosphide nanowires, which can split water into its hydrogen and oxygen components far more cheaply and efficiently than the batteries and semiconductor materials that have been used in the past.
Previous studies have shown that connecting an existing silicon solar cell to a water-splitting battery can produce hydrogen fuel, but it’s certainly not a cheap enough process to be a realistic alternative. The most promising option is using some kind of semiconductor material that can convert sunlight into an electrical charge while splitting water into useable components, like an all-in-one solar fuel cell, but semiconductor materials aren’t cheap either.
A team Eindhoven University of Technology investigated the potential of gallium phosphide (GaP), which is a compound of gallium and phosphide that’s also used in the production of red, orange, and green-coloured LED lights, and has shown great potential in terms of its electrical properties. But gallium phosphide is expensive to produce, and when used in big, flat sheets, it’s not capable of absorbing sunlight as efficiently as needed for a viable solar cell system. So the researchers tried producing a grid of tiny gallium phosphide nanowires measuring 90 nanometres thick and 500 nanometers long, and integrated them with existing solar cell technology.
Not only did they end up using 10,000 less gallium phosphide than if they’d used it to build a flat surface, but they discovered a whole new way to make solar fuel. “This immediately boosted the yield of hydrogen by a factor of 10 to 2.9 percent,” the press release explains. “A record for GaP cells, even though this is still some way off the 15 percent achieved by silicon cells coupled to a battery.” Edited from: Scientists figure out how to make solar cells produce fuel AND electricity