FLUORESCENT SUBSTANCE AND ITS MANUFACTURING METHOD, COMPOSITION CONTAINING FLUORESCENT SUBSTANCE, LIGHT EMITTING DEVICE, IMAGE DISPLAY DEVICE, AND ILLUMINATING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a high performance fluorescent substance for emitting a green fluorescence, having the excellent conversion efficiency with respect to a blue light or a near-ultraviolet light and color purity.

SOLUTION: The fluorescent substance satisfies (i) the emission peak wavelength in the case of excitation with a light with the peak wavelength of 400 nm or 455 nm of 510 nm to 542 nm, (ii) the emission peak half band width in the case of excitation with a light with the peak wavelength of 400 nm or 455 nm of 75 nm or less, (iii) the external quantum efficiency in the case of excitation with a light with the peak wavelength of 400 nm or 455 nm of 0.42 or more: (external quantum efficiency)=(internal quantum efficiency)×(absorption efficiency), (iv) at least a part of the surface of the fluorescent substance made of a substance containing oxygen, and (v) inclusion of a metallic element (MIIelement) to be divalent or trivalent and the ratio of the moles of the MIIelement with respect to the total moles of the divalent elements included in the fluorescent substance of 1% or more and less than 15%.

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