PHOSPHOR POWDER, PHOSPHOR-CONTAINING COMPOSITION, LIGHT-EMITTING ELEMENT, AND LIGHT-EMITTING DEVICE
Provided are a phosphor powder having a sufficiently high absorption rate and high internal quantum efficiency, a phosphor-containing composition, a light-emitting element, and a light-emitting device. The phosphor powder is such that the total volume frequency of particles having a grain size of less than 2.5 μm as measured by a laser diffraction scattering grain size distribution measurement method is 10% or greater, the total volume frequency of particles having a grain size of 2.5-10 μm is 10-90%, and the cumulative 50% diameter (D50) in the volume grain size distribution is 10.0 μm or less.
1 . A phosphor powder comprising, as measured by laser diffraction scattering particle size distribution measurement: particles with a particle diameter of less than 2.5 μm at a cumulative volume frequency of 10% or more; and particles with a particle diameter of 2.5 μm or more and 10.0 μm or less at a cumulative volume frequency of 10% or more and 90% or less, the phosphor powder having a volume particle size distribution with a 50% cumulative diameter (D50) of 10.0 μm or less.
2 . The phosphor powder according to claim 1 , wherein the phosphor powder has a volume frequency distribution curve plotted with the common logarithm of particle diameter on a horizontal axis, volume frequency on a vertical axis, and a maximum volume frequency being normalized to 1 and has a peak area, which is an area enclosed by the volume frequency distribution curve and the horizontal axis, of 12 or more.
3 . The phosphor powder according to claim 1 , wherein, as measured by laser diffraction scattering particle size distribution measurement, the phosphor powder has a volume particle size distribution with a particle size distribution ratio of 0.7 or more, wherein the particle size distribution ratio is calculated as (D80−D20)/D50 from a 20% cumulative diameter (D20), a 50% cumulative diameter (D50), and an 80% cumulative diameter (D80) of the volume particle size distribution.
4 . The phosphor powder according to claim 1 , wherein the phosphor powder comprises a luminescent center; and at least one of a crystal matrix comprising gallium (Ga), sulfur (S), and at least one metal element selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca) or a crystal matrix comprising sulfur (S) and at least one metal element selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca).
5 . A phosphor-containing composition comprising a phosphor powder comprising, as measured by laser diffraction scattering particle size distribution measurement: particles with a particle diameter of less than 2.5 μm at a cumulative volume frequency of 10% or more; and particles with a particle diameter of 2.5 μm or more and 10.0 μm or less at a cumulative volume frequency of 10% or more and 90% or less, the phosphor powder having a volume particle size distribution with a 50% cumulative diameter (D50) of 10.0 μm or less.
6 . The phosphor-containing composition according to claim 5 , wherein the phosphor powder has a volume frequency distribution curve plotted with the common logarithm of particle diameter on a horizontal axis, volume frequency on a vertical axis, and a maximum volume frequency being normalized to 1 and has a peak area, which is an area enclosed by the volume frequency distribution curve and the horizontal axis, of 12 or more.
7 . The phosphor-containing composition according to claim 5 , wherein, as measured by laser diffraction scattering particle size distribution measurement, the phosphor powder has a volume particle size distribution with a particle size distribution ratio of 0.7 or more, wherein the particle size distribution ratio is calculated as (D80−D20)/D50 from a 20% cumulative diameter (D20), a 50% cumulative diameter (D50), and an 80% cumulative diameter (D80) of the volume particle size distribution.
8 . The phosphor-containing composition according to claim 5 , wherein the phosphor powder comprises a luminescent center; and at least one of a crystal matrix comprising gallium (Ga), sulfur (S), and at least one metal element selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca) or a crystal matrix comprising sulfur (S) and at least one metal element selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca).
9 . A light-emitting element comprising: the phosphor-containing composition according to claim 5 ; and an excitation source.
10 . A light-emitting device comprising the light-emitting element according to claim 9 .