An object of the invention is to provide a blue-green light-emitting phosphor having excellent high-temperature property and excellent light-emitting properties such as brightness and half width. The phosphor is constituted of a plurality of alkaline earth metal elements including a barium element, phosphoric acid and a halogen element, and Eu as an activator, in which the molar ratio of the barium element to the total content of the alkaline earth metal elements is larger than 60% and smaller than 95%, and upon irradiation with a near-ultraviolet ray, the blue-green light-emitting phosphor is excited to thereby emit blue-green visible light.

An object of the invention is to provide a blue-green light-emitting phosphor having excellent high-temperature property and excellent light-emitting properties such as brightness and half width. The phosphor is constituted of a plurality of alkaline earth metal elements including a barium element, phosphoric acid and a halogen element, and Eu as an activator, in which the molar ratio of the barium element to the total content of the alkaline earth metal elements is larger than 60% and smaller than 95%, and upon irradiation with a near-ultraviolet ray, the blue-green light-emitting phosphor is excited to thereby emit blue-green visible light.

There is provided a red phosphor that may include a nitride represented by a formula of (Sr.sub.1-x-yBa.sub.xEu.sub.y).sub.2Si.sub.5N.sub.8, wherein 0<x<0.7, and 0<y<0.1. The red phosphor may emit light having a peak wavelength in a range of 600 nm to 630 nm when irradiated by an excitation source and the excitation source may be a blue light source having a dominant wavelength in a range of 420 nm to 470 nm.

There is provided a red phosphor that may include a nitride represented by a formula of (Sr.sub.1-x-yBa.sub.xEu.sub.y).sub.2Si.sub.5N.sub.8, wherein 0<x<0.7, and 0<y<0.1. The red phosphor may emit light having a peak wavelength in a range of 600 nm to 630 nm when irradiated by an excitation source and the excitation source may be a blue light source having a dominant wavelength in a range of 420 nm to 470 nm.

A quantum dot includes: a core including at least one first positive ion precursor and at least one negative ion precursor; a shell including at least one second positive ion precursor and at least one negative ion precursor and wrapping the core; and a ligand formed on a surface of the shell, wherein the first positive ion precursor is an n-period element and the second positive ion precursor is an (n-1)-period element, where n is an integer of 3 to 6.

A quantum dot includes: a core including at least one first positive ion precursor and at least one negative ion precursor; a shell including at least one second positive ion precursor and at least one negative ion precursor and wrapping the core; and a ligand formed on a surface of the shell, wherein the first positive ion precursor is an n-period element and the second positive ion precursor is an (n-1)-period element, where n is an integer of 3 to 6.

This invention provides an orange-yellow-emitting phosphor, the preparation method and the use thereof. This orange-yellow-emitting phosphor has a general formula represented by formula I: Sr.sub.9?a?b?xM.sub.aMg.sub.1.5+b(PO.sub.4).sub.7:xEu.sup.2+ formula I; wherein in formula I, said M is one or two of Ca and Ba; and 0.001?x?0.9, 0?a?1.0, 0?b?2.3. This orange-yellow-emitting phosphor uses a phosphate as the host material and Eu.sup.2+ ions as activation ions. The chemical properties of the phosphor are stable. The phosphor has relatively wide excitation band and emission band. And the red component in its emission spectrum is abundant, therefore, coupling the blue InGaN chip with the orange-yellow-emitting phosphor provided by this invention can obtain warm white light. The phosphor is radiation free, therefore, it will not be harmful to the environment. It is indicated by experimental results that this orange-yellow-emitting phosphor can be effectively excited by light at a wavelength of 250-500 nm and emits a wide peak at 470-850 nm, wherein the main emission peaks lie at about 523 nm and 620 nm. This preparation method is simple, and the cost is relatively low, so it is amenable to industrial production.

This invention provides an orange-yellow-emitting phosphor, the preparation method and the use thereof. This orange-yellow-emitting phosphor has a general formula represented by formula I: Sr.sub.9?a?b?xM.sub.aMg.sub.1.5+b(PO.sub.4).sub.7:xEu.sup.2+ formula I; wherein in formula I, said M is one or two of Ca and Ba; and 0.001?x?0.9, 0?a?1.0, 0?b?2.3. This orange-yellow-emitting phosphor uses a phosphate as the host material and Eu.sup.2+ ions as activation ions. The chemical properties of the phosphor are stable. The phosphor has relatively wide excitation band and emission band. And the red component in its emission spectrum is abundant, therefore, coupling the blue InGaN chip with the orange-yellow-emitting phosphor provided by this invention can obtain warm white light. The phosphor is radiation free, therefore, it will not be harmful to the environment. It is indicated by experimental results that this orange-yellow-emitting phosphor can be effectively excited by light at a wavelength of 250-500 nm and emits a wide peak at 470-850 nm, wherein the main emission peaks lie at about 523 nm and 620 nm. This preparation method is simple, and the cost is relatively low, so it is amenable to industrial production.

An object of the invention is to provide a blue-green light-emitting phosphor having excellent high-temperature property and excellent light-emitting properties such as brightness and half width. The phosphor is constituted of a plurality of alkaline earth metal elements including a barium element, phosphoric acid and a halogen element, and Eu as an activator, in which the molar ratio of the barium element to the total content of the alkaline earth metal elements is larger than 60% and smaller than 95%, and upon irradiation with a near-ultraviolet ray, the blue-green light-emitting phosphor is excited to thereby emit blue-green visible light.

An object of the invention is to provide a blue-green light-emitting phosphor having excellent high-temperature property and excellent light-emitting properties such as brightness and half width. The phosphor is constituted of a plurality of alkaline earth metal elements including a barium element, phosphoric acid and a halogen element, and Eu as an activator, in which the molar ratio of the barium element to the total content of the alkaline earth metal elements is larger than 60% and smaller than 95%, and upon irradiation with a near-ultraviolet ray, the blue-green light-emitting phosphor is excited to thereby emit blue-green visible light.