Yellow is not the new black: discovery paves way for new generation of solar cells

By stabilizing perovskites -man-made crystals that can convert sunlight into electricity- they absorb sunlight and can be used in efficient solar panels. Perovskites are semiconductor materials that have many applications. They show particular promise in harvesting solar energy. Currently, most solar cells are made with silicon crystals, a relatively straightforward and effective material to process for this purpose. However, perovskite-based devices offer higher conversion efficiencies than silicon. The only problem: some of the most promising perovskites, namely caesium lead triiodide (CsPbI₃), are very unstable at room temperature. Under these conditions, they have a yellow colour, as the atoms in the crystal do not form a perovskite structure.