We may not have come to the point where coal, the unprepossessing allotrope of carbon, could be transformed to the girl's-best-friend allotrope, diamond. Scientists at Rice University, however, have devised an ingenious, yet simple way of transfiguring coal to synthesize graphene quantum dots GQS: nano-sized graphene oxide discs, one atom thick that could eventually supplant the traditional quantum dots in use today. Conventional manufacturing methods of quantum dots only produce minute quantities, and at very high costs. Typically, quantum dots are manufactured from semiconductor materials, which emit photons with wavelengths depending on the size of the dot, transitioning from red to blue as the size gets smaller. The unique optical properties are exhibited due to the dot's size (the energy gap between the conduction band and the valence band which grows with decreasing particle size) and not on the material itself. Scientists at Rice University cleverly picked the cheapest carbon as their raw material, using three varieties to yield different types of dots. Coal was made to undergo an oxidation process by pulverizing the coal and following it with an acid treatment to break the bonds. The three different sources of coal were used to synthesize different-sized nanoparticles. This cheap source of GQD has the potential to replace the more expensive semiconductor-derived quantum dots, with applications ranging from medical imaging, photovoltaics, screen displays to usage as antioxidants. You can learn more about this research here, and in the video.