The luminous efficiency of white light-emitting diodes, which are used as light sources fornext-generation illumination, is continuously improving. Presently available white lightemitting diodes emit with extremely high luminance because their emission areas are much smaller than those of conventional light sources. Consequently, white light-emitting diodesproduce a glare that is uncomfortable to the human eye. Here we report a yellow-emittingphosphor, the Eu2+-doped chlorometasilicate (Ca1-x-y,srx,Euy)7(sio3)6Cl2, which can beused to create glareless white light-emitting diodes. The (Ca1-x-y,srx,Euy)7(sio3)6Cl2 exhibitsa large stokes shift, efficiently converting violet excitation light to yellow luminescence, andphosphors 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, andwe used (Ca1-x-y,srx,Euy)7(sio3)6Cl2 and a blue-emitting phosphor in combination with a violetchip to fabricate glareless white light-emitting diodes that have large emission areas and aresuitable for general illumination.
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