An object is to provide a new type of near-infrared ray-emitting phosphor which exhibits excellent emission intensity. A near-infrared ray-emitting phosphor is represented by a general formula, (Y, Lu, Gd).sub.3-x-y (Ga,Al,Sc).sub.5O.sub.12:(Cr.sub.x,(Yb,Nd).sub.y) (0.05<x<0.3, 0≤y<0.3).

A core-shell quantum dot comprising zinc, a core comprising a first semiconductor nanocrystal material; and a semiconductor nanocrystal shell disposed on the core, wherein the core-shell quantum dot does not comprise cadmium, and does comprise zinc, tellurium, selenium, and aluminum.

A core-shell quantum dot comprising zinc, a core comprising a first semiconductor nanocrystal material; and a semiconductor nanocrystal shell disposed on the core, wherein the core-shell quantum dot does not comprise cadmium, and does comprise zinc, tellurium, selenium, and aluminum.

A wavelength converter 100 includes: a first phosphor 1 composed of an inorganic phosphor activated by Ce.sup.3+; and a second phosphor 2 composed of an inorganic phosphor activated by Ce.sup.3+ and different from the first phosphor. At least one of the first phosphor and the second phosphor is particulate. The first phosphor and the second phosphor are bonded to each other by at least one of a chemical reaction in a contact portion between the compound that constitutes the first phosphor and a compound that constitutes the second phosphor and of adhesion between the compound that constitutes the first phosphor and the compound that constitutes the second phosphor.

According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.

According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.

A light emitting device including a housing including walls defining a cavity having one side thereof opened, a light emitter to emit light having a peak wavelength in a blue wavelength band and including first and second light emitting chips, a reflective region in the housing to reflect light, and a wavelength conversion layer disposed on the light emitter and including a first wavelength converter and a second wavelength converter to emit light having different peak wavelengths from each other, in which the first wavelength converter has a first excitation peak wavelength and the second wavelength converter has a second excitation peak wavelength, and the second wavelength converter includes a fluoride-based red phosphor represented by A.sub.2MF.sub.6:Mn.sup.4+, where A is one of Li, Na, K, Ba, Rb, Cs, Mg, Ca, Se, and Zn, and M is one of Ti, Si, Zr, Sn, and Ge.

An optical member includes a first light guide member having an elongated shape and comprising an end surface and a lateral surface extending in a longitudinal direction from the end surface; and a wavelength conversion layer disposed on the lateral surface of the first light guide member and containing a phosphor.

Provided is a method for producing a fluoride phosphor. The method includes: providing a first solution containing an element M.sup.1 containing at least one selected from the group consisting of group 13 elements, manganese, and fluorine, a second solution containing an element M.sup.2 containing at least one selected from the group consisting of group 4 elements and group 14 elements, and a third solution containing at least one selected from the group consisting of alkali metal elements; and adding the second solution and the third solution to the first solution at substantially the same time.

Phosphors include a CaAlSiN.sub.3 family crystal phase, wherein the CaAlSiN.sub.3 family crystal phase comprises at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb.