We know that ‘Solar Cells’ are more efficient and promising devices than other “fossil fuels’ in the world but the one and only one problem with them is that ; “what to do when there is no sunshine or cloudy on sky.??” , this this the biggest problem with solar cells. But Led by Michael Graetzel, director of the Laboratory of Photonics and Interfaces at the Ecole Polytechnique in Switzerland, and team of scientists has invented a solar device with a new type of material that can store sunlight more efficiently then other solar panels in the market and convert this energy directly into ‘Hydrogen’ , this energy then can be stored or burned as fuel or fed through a fuel cell to generate electricity.
Named a ‘water splitter’, the device has been tipped as the next big thing in solar technology, says Kevin Bullis at MIT’s Technology Review, because it meets three of the four criteria needed to create a practical device. First it made up with a new type of material called perovskite which is discovered in 2009 and found to absorb sunlight much more efficiently then currently made solar panels (by silicon). According to Bullis, it can store 12.3 percent of the energy in sunlight in the form of hydrogen, which is pretty huge, seeing as 10 percent is the accepted benchmark for efficient solar-hydrogen converters.
Secondly it is cheaper then currently silicon cells and thirdly these materials are abundant to source, so the device is also easy to make. On top of perovskite, the device uses cheap nickel and iron to act as catalysts in its two ‘water-splitting’ electrodes – one that produces hydrogen and one that produces oxygen when they react with water.
The fourth criteria needed for a practical device is reliability, which the team is now working on increasing. Right now, it only lasts for a few hours before the performance of the solar cell starts to decrease. This is because perovskite degrades much faster than silicon. But the team, which includes researchers from Switzerland, Singapore and Korea, has figured out how to extend this lifespan to over a month by adding a layer of carbon to it. They’ve published their results in the journal Science. They’re now working on increasing this further.