Ca 1 −− x Li x Al 1 − x Si 1+1+ x N 3 :Eu 2+ solid solutions as broadband, color-tunable and thermally robust red phosphors for superior color rendition white light-emitting diodes

A new red phosphor with broadband emission has yielded white LEDs that have both a high luminous efficacy and excellent colour rendering. By applying structure and bandgap engineering strategies, Rong-Jun Xie and co-workers from China, Japan and the USA fabricated their rare-earth phosphor from Ca1−xLixAl1−xSi1+xN3:Eu2+. They say that the introduction of LiS2N3 to CaAlSiN3:Eu2+ minimizes the usual trade-off between emission colour and efficiency. When the red phosphor was combined with a commercial blue InGaN LED and a green phosphor, the result was a white LED with a luminous efficacy exceeding 100 lumens per watt and a high colour rendering. The researchers note that in addition to superior colour quality, the use of LiS2N3 imparts better thermal stability to the phosphor compared with currently used red phosphors.