Ca2Si(O4-xNx):Eu2+绿色荧光粉的制备及其发光性能
Preparation and luminescent prop erties of Ca2Si(O4-xNx):Eu2+ green-emitting phosphors
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摘要: 利用在Ca-Si-O干凝胶前驱体中添加Si3N4的方法于非还原气氛下合成了含N固溶体Ca2Si(O4-xNx):Eu2+绿色荧光粉.通过X射线衍射仪、扫描电子显微镜以及荧光分光光度计分别分析了产物的物相结构、颗粒形貌和发光性能.结果显示, Si3N4与前驱体的混合物在非还原气氛(纯氮气)下于1100?C焙烧后获得含N固溶体Ca2Si(O4-xNx):Eu2+荧光粉,特别是其中Eu3+被还原为Eu2+,产物的晶体结构与β-Ca2SiO4相一致. Ca2Si(O4-xNx):Eu2+能够被270-400 nm 范围内的紫外线有效激发,其发射光谱呈宽带发射.随着N含量的增加,发射峰出现一定程度红移(501-504 nm),而且发光强度显著提高.当Eu2+浓度为0.25 mol%时发光强度达最大值,浓度超过0.25 mol%时,发光强度显著降低,出现浓度猝灭效应.Abstract: A nitrogen-contained solid solution Ca2Si(O4-xNx):Eu2+ green phosphors was successfully synthesized using the method of mixing Ca-Si-O xerogel precursor with Si3N4 powders in a non-reducing atmosphere (pure nitrogen). The structure, morphology, and luminescent properties of the phosphors are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectra. Results show that the Ca2Si(O4-xNx):Eu2+is obtained and especially the reduction of Eu3+ to Eu2+ occurs when the mixture of Si3N4 and precursor is calcined at 1100 ?C in pure nitrogen atmosphere. XRD results show that the crystalline structure of N-contained solid solu-tion Ca2Si(O4-xNx):Eu2+ is consistent with that of β-Ca2SiO4 phase. The phosphors can be efficiently excited at a wavelength of 270-400 nm and shows a single intense broadband emission (450-600 nm). Significantly, the red-shift (501 nm to 504 nm) of emission peak occurs and the luminescent intensity is improved significantly with increasing N concentration. With increasing Eu2+ concentration, luminescent intensity of the phosphors increases continuously and reaches a maximum value at the concentration of 0.25 mol%Eu2+. Then the luminescent intensity decreases significantly and the concentration quenching effect appears when Eu2+ concentration is above 0.25 mol%.
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