Perovskites are not a material, but a crystalline structure that many compounds can assume, here made from lead, iodide and methylammonium at Stanford University (Palo Alto, Calif.) The researchers claim that their perovskites can harvest the high-energy photons that silicon solar cells miss, resulting in unwanted heat, allowing the output of normal silicon cells to be multiplied.

In the lab, the researchers claim to have achieved 17% efficiency by stacking a perovskite solar cell atop a cheap silicon cell rated at 11.4%. When stacking a perovskite solar cell atop a copper indium gallium diselenide (CIGS) cell they achieved a 18.6% efficiency.

The downside is that perovskite are fragile, dissolving in water and continuously degrading in light, nothing even close to the 25-year lifespan of silicon solar cells. Nevertheless, the Stanford researchers are working on making them more durable with a goal of a 25-year lifespan and 30% efficiency in five to 10 years.

Source: EEE Press