The present inventive concept relates to a hybrid wavelength converter including both a metal halide perovskite nanocrystal particles and non-perovskite-based quantum dots or non-perovskite-based phosphors converting a wavelength of light generated from an excitation light source to specific wavelengths, and a light-emitting device including the same. By including metal halide perovskite nanocrystal particles and non-perovskite quantum dots or non-perovskite phosphors in the dispersion medium, the hybrid wavelength converter according to the present inventive concept enables to make simultaneous wavelength conversion to red and green light, and to be optically stable and improved color purity and luminescence performance without changing the emission wavelength range even with a lower cadmium content than the conventional quantum dot wavelength converter.

A light emitting device is provided. The light emitting device includes a light emitting element, which emits blue light, and a light transmissive member having a first principal face bonded to the light emitting element and a second principal face opposite the first principal face. The light transmissive member has a light transmissive base material and wavelength conversion substances, which are contained in the base material and which absorb the light from the light emitting element and emit light. The wavelength conversion substances are localized in the base material towards the first principal face, and include a first phosphor which emits green to yellow light and a second phosphor which emits red light. The first phosphor is more localized towards the first principal face than the second phosphor. The second phosphor is a manganese-activated fluoride phosphor.

The disclosure provides processes for preparing etched quantum dots comprising Group II-VI and/or III-V elements. The processes include etching Group II-VI or III-V element quantum dots with an organic fluoride agent or ammonium salt and optionally shelling the etched quantum dots. The disclosure also provides processes for generating light from these quantum dots and devices, stains, or labels comprising the quantum dots prepared as described herein.

A wavelength conversion member includes: a light-transmissive member; and a wavelength conversion material located on a surface of the light-transmissive member and including: a resin, a phosphor with a median particle diameter of 10 μm or more and 30 μm or less, wherein an amount of the phosphor in the wavelength conversion material is 165 parts by mass or more and 400 parts by mass or less relative to 100 parts by mass of the resin, and a filler with a median particle diameter of 5 μm or more and 40 μm or less, wherein an amount of the filler in the wavelength conversion material is 5 parts by mass or more and 90 parts by mass or less relative to 100 parts by mass of the resin. A mixture volume ratio of the phosphor and the filler to the resin is 0.5 or more and 1.0 or less.

A light emitting device is provided. The light emitting device includes a light emitting element, which emits blue light, and a light transmissive member having a first principal face bonded to the light emitting element and a second principal face opposite the first principal face. The light transmissive member has a light transmissive base material and wavelength conversion substances, which are contained in the base material and which absorb the light from the light emitting element and emit light. The wavelength conversion substances are localized in the base material towards the first principal face, and include a first phosphor which emits green to yellow light and a second phosphor which emits red light. The first phosphor is more localized towards the first principal face than the second phosphor. The second phosphor is a manganese-activated fluoride phosphor.

A quantum dot includes a core-shell structure including a core including a first semiconductor nanocrystal and a shell disposed on the core, and including a material at least two different halogens, and the quantum dot does not include cadmium.

Synthesizing a color stable Mn.sup.4+ doped phosphor by contacting a gaseous fluorine-containing oxidizing agent with a precursor of: A.sub.aB.sub.bC.sub.cD.sub.dX.sub.x:Mn.sup.4+; A.sub.aiB.sub.biC.sub.ciD.sub.dX.sub.xY.sub.d:Mn.sup.4+; A.sup.1.sub.3G.sub.2mnMn.sub.mMg.sub.nLi.sub.3F.sub.12O.sub.p; or AZF.sub.4:Mn.sup.4+. Where A is Li, Na, K, Rb, Cs, or a combination; B is Be, Mg, Ca, Sr, Ba, or a combination; C is Sc, Y, B, Al, Ga, In, Tl, or a combination; D is Ti, Zr, Hf, Rf, Si, Ge, Sn, Pb, or a combination; X is F or a combination of F and one of Br, Cl, and I; Y is O, or a combination of O and one of S and Se; A.sup.1 is Na or K, or a combination; G is Al, B, Sc, Fe, Cr, Ti, In, or a combination; Z is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y, In, or a combination.

Provided are a luminescent compound represented by Formula 1, a method of preparing the same, and a light-emitting device including the same:

[A.sup.1.sub.nA.sup.2.sub.(3n)][B.sup.1.sub.mB.sup.2.sub.(2m)]X.sub.5 Formula 1

wherein, in Formula 1, A.sup.1, A.sup.2, B.sup.1, B.sup.2, n, m, and X are as defined in the specification.

A red phosphor comprising a first red phosphor and a second red phosphor having adjustable wavelength. The first red phosphor is made from a substance having structure formula M.sub.2AX.sub.6:Mn.sup.4+, wherein the element M is selected from Li, Na, K, Rb or Cs, the element A is selected from Ti, Si, Ge or Zr, and the element X is selected from F, Cl or Br; the ratio of the second red phosphor to the red phosphor ranges from 0.01% to 15%. Further provided is a white LED and a backlight module. The adjustably colored points of a device including M.sub.2AX.sub.6:Mn.sup.4+ are achieved by adding a second red phosphor having various wavelength to the red phosphor including M.sub.2AX.sub.6:Mn.sup.4+ whose emission wavelength and spectral shape cannot be adjusted. The device can enable full range of colored points with hardly any reduction of the NTSC color gamut.

A light emitting device is provided. The light emitting device includes a light emitting element, which emits blue light, and a light transmissive member having a first principal face bonded to the light emitting element and a second principal face opposite the first principal face. The light transmissive member has a light transmissive base material and wavelength conversion substances, which are contained in the base material and which absorb the light from the light emitting element and emit light. The wavelength conversion substances are localized in the base material towards the first principal face, and include a first phosphor which emits green to yellow light and a second phosphor which emits red light. The first phosphor is more localized towards the first principal face than the second phosphor. The second phosphor is a manganese-activated fluoride phosphor.