December 15, 2005 – A research group from Idemitsu Kosan Co. and Keio University has developed a way of producing YAG (yttrium aluminum garnet) phosphor in the form of a powder with particles measuring just 10nm dia., reports the Nikkei English News.
YAG phosphor is coated on blue LEDs to create light-emitting diodes that emit white light. The YAG phosphor material is typically processed into a powder with crystal grains measuring in the microns. But these particles are so big that they scatter light, reducing the brightness of the white LED.
The new nanopowder particles are smaller than the wavelength of the light, so there is almost no scattering. The result is a white LED that in principle can emit light that is 256 times as bright as a conventional white LED.
The YAG phosphor nanopowder is made by applying pressure to a liquid heated to 300C. The process not only yields smaller grains but is also less costly than conventional methods that bake the starting material at a temperature of 1000C.