Efficient, size-selected green-emitting phosphors

A composition of a phosphor of the formula

• SrGa2S4:Eu:xGa2S3 (I)
• wherein x is 0.0001 to 0.2, wherein a minor part of the europium component may be substituted with praseodymium in an efficiency enhancing amount, wherein the median grain size of the phosphor composition is from 2 to 4.5 microns, and wherein the quantum efficiency of the phosphor composition is 85% or more.

A light emitting device comprising:

• an LED light source that produces a light output;
• and
• a wavelength transformer comprising SrGa2S4:Eu:xGa2S3 wherein x is 0.0001 to 0.2, and wherein a minor part of the europium component is substituted with praseodymium in an efficiency enhancing amount, the wavelength transformer effective to, and located to, increase the light output having wavelength from 492 nm to 577 nm.

A light emitting device comprising:

• an LED light source that produces a light output;
• and
• a wavelength transformer comprising SrGa2S4:Eu:xGa2S3 wherein x is 0.0001 to 0.2, wherein a minor part of the europium component may be substituted with praseodymium in an efficiency enhancing amount, wherein the median grain size of the phosphor composition is from 2 to 4.5 microns, and wherein the quantum efficiency of the phosphor composition is 85% or more, the wavelength transformer effective to and located to, increase the light output having wavelength from 492 nm to 577 nm.

A composition of a phosphor of the formula

• SrGa2S4:Eu:xGa2S3 (I)
• wherein x is greater than 0.07 up to 0.2, wherein 0.05 mol percent to 4 mol percent of the europium component is substituted with praseodymium, and wherein the median grain size of the phosphor composition is from 2 to 4.5 microns.