You’re looking at a perovskite. Not an Eastern European bird of prey, nor an exotic toy to play with in the wind, but a potential future of solar power.
The materials, first discovered in 1839 but only recently used in solar applications, are defined not by the elements they contain but their crystalline structure. And that’s what you can see here: neat chunks of defect-free crystals manufactured at Los Alamos National Laboratory. Cheap compared to silicon crystals, these kinds of perovskites are even beginning to rival them in efficiency terms, because the lack of defects ensure that photons are neatly converted into electrons with few losses.