We report the preparation of 0.1% Eu3+; x% Gd3+ (0 ≤ x ≤ 1.2) ZnAl2O4 phosphors using the citrate sol–gel method. X-ray diffraction (XRD) data revealed that all annealed samples consisted of the single phase of cubic ZnAl2O4 structure. The scanning electron microscopic (SEM) images indicated pronounced effect of dual doping on the surface morphology of the phosphor. The estimated crystal sizes estimated by the XRD was confirmed by the high-resolution transmission electron microscopy (HR-TEM) to be approximately around 20 nm. The photoluminescence (PL) spectroscopy results revealed four distinct emission peaks located at 393, 400, 578 and 618 nm. The peaks at around 393 and 400 nm were attributed to the defect levels located at different positions on the host material (ZnAl2O4). The emission peak at 578 and 618 nm were attributed to the 5D0 → 7F1 and 2D0 → 7F2 characteristic transition within the Eu3+ ions. The International Commission on Illumination (CIE) colour coordinates revealed that the emission colour was not influenced by varying the concentration of Gd3+.

中文翻译：

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分析不同 Gd3+ 浓度对 ZnAl2O4:0.1% Eu3+ 的结构和光学性质的影响；x% Gd3+ (0 ≤ x ≤ 1.2) 通过柠檬酸盐溶胶-凝胶法合成

我们报告了 0.1% Eu3+ 的制备；x% Gd3+ (0 ≤ x ≤ 1.2) ZnAl2O4 荧光粉使用柠檬酸盐溶胶-凝胶法。X 射线衍射 (XRD) 数据表明，所有退火样品均由立方 ZnAl2O4 结构的单相组成。扫描电子显微镜 (SEM) 图像表明双掺杂对荧光粉表面形态的显着影响。由 XRD 估算的晶体尺寸经高分辨率透射电子显微镜 (HR-TEM) 证实约为 20 nm。光致发光 (PL) 光谱结果显示四个不同的发射峰位于 393、400、578 和 618 nm。393 和 400 nm 附近的峰值归因于位于主体材料 (ZnAl2O4) 上不同位置的缺陷水平。578 和 618 nm 处的发射峰归因于 Eu3+ 离子内的 5D0 → 7F1 和 2D0 → 7F2 特征跃迁。国际照明委员会 (CIE) 颜色坐标显示，发光颜色不受 Gd3+ 浓度变化的影响。