Phosphor and light-emitting device

1. A phosphor comprising:

a chemical composition expressed by the following formula

(K 1-p , M p ) a (Si 1-y , Mn y )F b

where M is at least one element selected from the group consisting of Na and Ca, and p satisfies 0≤p≤0.01, a satisfies 1.5≤a≤2.5, b satisfies 5.5≤b≤6.5, and y satisfies 0<y≤0.1,

wherein the phosphor has absorption peak in a range of 2,500-3,000 cm −1 and

satisfies I (2,500-3,000)/I (1,200-1,240)<0.04, where I (1,200-1,240) is an intensity of a highest peak in a range of 1,200-1,240 cm −1 and I (2,500-3,000) is an intensity of a highest peak in a range of 2,500-3,000 cm −1 in an infrared spectrum.

2. The phosphor according to claim 1 , wherein the phosphor has an internal quantum efficiency η′ of 95% or more.

3. The phosphor according to claim 1 , wherein the phosphor is activated with Mn 4+ .

4. The phosphor according to claim 1 , wherein the highest peak present in the range of 1,200-1,240 cm −1 is a peak inherent in K 2 SiF 6 .

5. The phosphor according to claim 1 , which is a red phosphor.

6. A light-emitting device, comprising:

a light-emitting element that emits light at the wavelength region of 430 nm or more and 470 nm or less, and

a phosphor layer comprising the phosphor according to claim 1 .

7. The light-emitting device according to claim 6 , wherein the phosphor layer further comprises a yellow light-emitting phosphor.

8. The light-emitting device according to claim 6 , wherein the phosphor layer further comprises a green light-emitting phosphor.

9. The phosphor according to claim 1 , wherein the phosphor satisfies:

I (2,500-3,000)/I (1,200-1,240)≤0.027.