Generation of “white light” is currently achieved by so called “white light emitting diodes (white LEDs)” that are constituted by employing a near-ultraviolet (UV) or blue emitting LED in conjunction with an inorganic phosphor or a blend of inorganic phosphors. Red-emitting phosphors based on complex fluoride materials activated by Mn4+, such as those described in U.S. Pat. Nos. 7,358,542, 7,497,973, and 7,648,649, absorb blue light strongly, and efficiently emit between about 610 nanometers and 635 nanometers with little deep red/NIR emission. Thus, the luminous efficacy and the quantum efficiency of white LEDs maximizes under blue excitation (440 nanometers-460 nanometers) as compared to other available red phosphors.
These complex fluorides can be utilized in combination with yellow-green emitting phosphors such as cerium-doped yttrium aluminum garnet Y3Al5O12:Ce3+ (YAG) or other garnet compositions to achieve warm white light (CCTs<5000 K on the blackbody locus, color rendering index (CRI)>80) from a blue LED, equivalent to that produced by current fluorescent, incandescent and halogen lamps. The benefits from using these complex fluoride phosphors are evident in LEDs used in LCD backlighting, where the complex fluoride phosphor is combined with an inorganic green phosphor. The emission position and full-width at half maximum (FWHM) of these complex fluoride phosphors enable a combination of high color gamut with high brightness. However, further improvements in color gamut and brightness are desirable.