Red light-emitting fluorescent substance and light-emitting device employing the same
The embodiment provides a red light-emitting fluorescent substance represented by the following formula (1): (M 1-x EC x ) a M 1 b AlO c N d (1). In the formula (1), M is an element selected from the group consisting of IA group elements, IIA group elements, IIIA group elements, IIIB group elements, rare earth elements and IVA group elements; EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi and Fe; M 1 is different from M and is selected from the group consisting of tetravalent elements; and x, a, b, c and d are numbers satisfying the conditions of 0<x<0.2, 0.63<a<0.80, 2.1<b<2.63, 0<c≦0.24 and 4<d<5, respectively. This substance emits luminescence having a peak in the wavelength range of 620 to 670 nm when excited by light of 250 to 500 nm.
1. A fluorescent substance having formula (1):
(M 1-x EC x ) a M 1 b AlO c N d (1),
wherein:
M is an element selected from the group consisting of IA group elements, IIA group elements, IIIA group elements, IIIB group elements, rare earth elements, and IVA group elements;
EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi, and Fe;
M 1 is different from M and is selected from the group consisting of tetravalent elements; and
x, a, b, c and d are numbers satisfying the conditions of 0<x<0.2, 0.63<a<0.80, 2.1<b<2.63, 0<c≦0.24, and 4<d<5, respectively; and
emitting luminescence having a peak in the wavelength range of 620 to 670 nm under excitation by light in the wavelength range of 250 to 500 nm.
2. The fluorescent substance of claim 1 , wherein M 1 is Si.
3. The fluorescent substance of claim 1 , wherein M is an element selected from the group consisting of Li, Na, K, Mg, Ca, Sr, Ba, B, In, Ga, Y, Sc, Gd, La, Lu, and Ge.
4. The fluorescent substance of claim 1 , wherein b is a number satisfying the condition of 2.1<b<2.5.
5. The fluorescent substance of claim 1 , wherein c is a number satisfying the condition of 0.05<c≦0.21.
6. The fluorescent substance of claim 4 , wherein c is a number satisfying the condition of 0.05<c≦0.21.
7. The fluorescent substance of claim 5 , wherein c is a number satisfying the condition of 0.15<c≦0.21.
8. The fluorescent substance of claim 1 , wherein M is an element selected from the group consisting of Li, Ca, Sr, and Ba.
9. The fluorescent substance of claim 1 , wherein M is Sr.
10. The fluorescent substance of claim 1 , wherein EC is Eu.
11. The fluorescent substance of claim 8 , wherein EC is Eu.
12. The fluorescent substance of claim 9 , wherein EC is Eu.
13. The fluorescent substance of claim 1 , synthesized from a mixture comprising:
a nitride, carbide, or cyanamide of the element M;
a nitride, oxide, or carbide of Al;
a nitride, oxide, or carbide of the element M 1 ; and
an oxide, nitride, or carbonate of the emission center element EC.
14. The fluorescent substance of claim 1 , synthesized from a mixture comprising Sr 3 N 2 , AlN, Si 3 N 4 , Al 2 O 3 , and EuN.
15. The fluorescent substance of claim 1 , synthesized from a mixture comprising Sr 3 N 2 , AlN, Si 3 N 4 , and EuN.
16. The fluorescent substance of claim 13 , obtained by firing the under a pressure more than the atmospheric pressure.
17. The fluorescent substance of claim 13 , obtained by firing the mixture under a N 2 or N 2 /H 2 atmosphere.
18. The fluorescent substance of claim 13 , obtained by firing the mixture at a temperature in the range of 1500 to 2000° C.
19. The fluorescent substance of claim 13 , obtained by firing the mixture at a temperature in the range of 1800 to 2000° C.