A method for creating inorganic LEDs emitting light in the ultraviolet range is reported in Nature Communications this week. The work represents a step towards generating nanostructured systems that can be used as active components in biomedical devices. Light emitting diodes based on inorganic nanocrystals are considered to be promising for use in environmental and biomedical diagnostics, since they are cheap, robust and chemically stable. However, their widespread use has been hampered as they do not emit ultraviolet light. Sergio Brovelli and colleagues present a fabrication process that overcomes this problem, and opens the way for their integration in a variety of designer applications.