Record breaking Perovskite solar cells may soon replace their silicon based counterparts. Scientists have solved a problem resulting from thermal instability and are now attempting to extend their lifespan.
Solar panels made of Perovskite – a compound of Cadmium, Titanium and Oxygen hold much promise for the future of solar power. A type of thin film solar panel spotted with a series of tuneable bandgaps that allow the absorption of light across a large range of electromagnetic wavelengths – Their record breaking power conversion efficiency of 23%+ rivals that of mainstream silicon based solar panels.
Perovskite structure. Red: O2, Large Blue: Ca2+, Small Blue: Ti4+
The best Perovskite solar cells contain bromide and methylammonium unfortunately these compounds are also what make the panel unstable. So scientists replaced methylammonium with another compound called formamidinium (FA).
Unfortunately this created a new problem. FA begins to produce an unusable “yellow phase” at room temperature, while the useful black phase remains out of reach at high temperatures.
So, Researchers led by Michael Saliba of the Adolphe Merkle Institute and Anders Hagfeldt of the Ecole Polytechnique Fédérale de Lausanne replaced the Bromine with Iodine and methylammonium with a mix of Rubidium and Caesium in order to bring down the useful Black phase for operation at room temperature. This seemed to do the trick and the panels are now sitting at a power conversion efficiency of 20.35% – a record for non methylammonium based solar cells.
The study was published in Science 10.1126/science.aat3583
However, since Perovskite solar cells only last around 100 hours they’re not quite ready for commercialization. Now scientists will work towards extending their lifespan. “This is obviously not long enough for practical applications, so we need to extend this to over 10 000 hours or even 100 000 hours,” he tells Physics World.