In a recent communication in the Journal of the American Chemical Society, postdoctoral fellow James Puthussery, graduate students Sean Seefeld, Nick Berry, and Mark Gibbs, and Prof. Matt Law report the synthesis of phase-pure, single-crystalline, and well-dispersed colloidal iron pyrite (FeS2) nanocrystals by a simple hot-injection route. Polycrystalline pyrite thin films are fabricated by sintering layers of these nanocrystals at 500-600°C in sulfur atmosphere. Pyrite is a promising earth-abundant semiconductor for thin film solar cells.