Scientists have developed multicolor LEDs without heavy metals. These nanocrystals consist of a few hundred to thousand atoms and have a considerable potential as highly efficient light emitters, as was demonstrated by the team of Professor Uli Lemmer and Professor Annie K. Powell from KIT as well as Professor Geoffrey A. Ozin from the University of Toronto. In a joint project, the scientists have now succeeded in manufacturing highly efficient LEDs from the silicon nanocrystals. So far, manufacture of silicon LEDs has been limited to the red visible spectr...