A novel phosphor for glareless white light-emitting diodes

摘要

The luminous efficiency of white light-emitting diodes, which are used as light sources for next-generation illumination, is continuously improving. Presently available white light-emitting diodes emit with extremely high luminance because their emission areas are much smaller than those of conventional light sources. Consequently, white light-emitting diodes produce a glare that is uncomfortable to the human eye. Here we report a yellow-emitting phosphor, the Eu2+-doped chlorometasilicate (Ca_1-x-y,Sr_x,Eu_y)₇(SiO₃)₆Cl₂, which can be used to create glareless white light-emitting diodes. The (Ca_1-x-y,Sr_x,Eu_y)₇(SiO₃)₆Cl₂ exhibits a large Stokes shift, efficiently converting violet excitation light to yellow luminescence, and phosphors based on this host material have much less blue absorption than other phosphors. We used crystal structure analysis to determine the origin of the desired luminescence, and we used (Ca_1-x-y,Sr_x,Eu_y)₇(SiO₃)₆Cl₂ and a blue-emitting phosphor in combination with a violet chip to fabricate glareless white light-emitting diodes that have large emission areas and are suitable for general illumination.. ? 2012 Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.