Red phosphors for solid state lighting
View Patent ↗A red phosphor composition in combination with a semiconductor light emitting device (e.g., VCSEL, LED, or LD), preferably a GaN based device, that emits light at a bright violet-blue light range, i.e., having a wavelength in the range of 400 nm to 600 nm, which can be further combined with green and blue phosphors. The red phosphor composition in the combination is a vanadate combined with yttrium, gadolinium and/or lanthanum and activated with trivalent Eu 3+ , Sm 3+ and Pr 3 30 , or any combination thereof, with or without Tb 3+ as a co-dopant, has the general formula: Bi x Ln 1-x VO 4 :A where x=0 to 1, Ln is an element selected from the group consisting of Y, La and Gd, and A is an activator selected from Eu 3+ , Sm 3+ and Pr 3+ , or any combination thereof, with or without Tb 3+ as a co-dopant. Novel red phosphor compositions are provided when x is greater than 0 and less than 1, preferably 0.05 to 0.5.
1. A light emitting GaN based device, comprising:
a semiconductor device capable of emitting light having a wavelength in the range of 200 nm to 620 nm; a blue phosphor; and a red phosphor having the formula:
Bi x Ln 1-x VO 4 :A
where X is 0.05 to 0.5, Ln is an element selected from the group consisting of Y, La and Gd, and A is an activator selected from Eu 3+ , Sm 3+ and Pr 3+, or any combination thereof.
2. The device of claim 1 in which the red phosphor is capable of absorbing light of a wavelength in the range of 240 nm to 550 nm and capable of emitting red light at a wavelength in the range of 580 nm to 700 nm.
3. The device of claim 1 in which the semiconductor device comprises a vertical cavity surface emitting laser, a light emitting diode, or a laser diode.
4. A light emitting GaN based device of claim 1 , further comprising Tb 3+ as a co-dopant.
5. A light emitting device, comprising:
a semiconductor device capable of emitting light having a wavelength in the range of 200 nm to 620 nm; and
a red phosphor having a formula of
Bi x Ln 1-x VO 4 :A
where x=0 to 1, Ln is an element selected from the group consisting of Y, La and Gd, and A is Tb 3+ and at least one activator selected from Eu 3+ , Sm 3+ and Pr 3+ or any combination thereof.
6. The device of claim 5 in which x is greater than 0 and less than 1.
7. The device of claim 6 in which x is 0.05 to 0.5.
8. A white light emitting phosphor combination, comprising:
a red phosphor having the formula of:
Bi x Ln 1-x VO 4 :A
where x is 0.05 to 0.5, Ln is an element selected from the group consisting of Y, La and Gd, and A is an activator selected from Eu 3+ , Sm 3+ and Pr 3+ , or any combination thereof,
a green phosphor; and
a blue phosphor.
9. A white light emitting phosphor combination of claim 8 , further comprising Tb 3+ as a co-dopant.
10. A light emitting GaN based device, comprising:
a semiconductor device capable of emitting light having a wavelength in the range of 200 nm to 620 nm; a blue phosphor; and a red phosphor having the formula:
Bi x Ln 1-x VO 4 :A
where x is greater than zero and less than 1, Ln is an element selected from the group consisting of Y, La and Gd, and A is an activator selected from Sm 3+ and Pr 3+, or any combination thereof.
11. A light emitting GaN based device of claim 10 , further comprising further comprising Tb 3+ as a co-dopant.