Light emitting device having sulfoselenide fluorescent phosphor

A composition of matter useful as a phosphor in light emitting diodes, which comprises a material described by the formula:

• ZnSxSey:Cu,A
• in which x and y are each independently any value between 0 and about 1, subject to the proviso that the sum of x and y is equal to any number in the range of between about 0.75 and about 1.25;
• and subject to the proviso that x is not zero, wherein A comprises at least one additional element selected from the group consisting of:
• Ag, Ce, Tb, Cl, I, Mg, and Mn, including mixtures thereof, and wherein Cu is present in any amount between about 0.0001% and about 5% in mole percent based on the total molar weight of said composition, and wherein 0.001≦x≦0.5 and 0≦y≦0.5.

A composition of matter useful as a phosphor in light emitting diodes, which comprises a material described by the formula:

• ZnSxSey:Cu,A
• in which x and y are each independently any value between 0 and about 1, subject to the proviso that the sum of x and y is equal to any number in the range of between about 0.75 and about 1.25;
• and subject to the proviso that x is not zero, wherein A comprises at least one additional element selected from the group consisting of:
• Ag, Ce, Tb, Cl, I, Mg, and Mn, including mixtures thereof, and wherein Cu is present in any amount between about 0.0001% and about 5% in mole percent based on the total molar weight of said composition, and wherein 0.001≦x≦0.5 and 0.5≦y≦1.0.