Jung Jae-Yong, Kim Juna, Shim Young-Seok, Hwang Donghyun, Son Chang Sik
Division of Materials Science and Engineering, Silla University, Busan 46958, Korea.
School of Materials Science and Engineering, Pusan National University, Busan 46241, Korea.
Materials (Basel). 2020 Sep 19;13(18):4165. doi: 10.3390/ma13184165.
Barium tungstate (BaWO) powders with various sintering temperatures, and BaWO:Dy phosphor samples with concentrations of different rare-earth (RE) activator ions (Dy, Sm, Tb) were prepared through co-precipitation. The structural, morphological, and photoluminescent characteristics of barium tungstate phosphors depend on the concentration of RE ions. The crystallographic characteristics of the synthesized BaWO were analyzed using X-ray diffraction (XRD) patterns. The size and shape of the crystalline particles were estimated based on images measured with a field emission scanning electron microscope (FE-SEM). As the sintering temperature of the BaWO particles increased from 400 °C to 1000 °C, the size of the particles gradually increased and showed a tendency to clump together. In the sample doped with 7 mol % Dy ions, the intensity of all emission bands reached their maximum. The emission spectra of the RE-doped BaWO powders by excitation at 325 nm were composed of yellow (Dy), red (Sm+), and green (Tb) band at 572, 640, and 544 nm. This indicates that most of the RE ions absorbed the position without reversal symmetry in the BaWO lattice. These results propose that strong emission intensity and tunable color for the phosphors can be accomplished by rare-earth doped host with an suitable quantity. In addition, the phosphor thin films, having high transparency from aqueous colloidal solutions, were deposited on banknotes, and it is considered whether it is suitable for anti-counterfeiting applications.
通过共沉淀法制备了具有不同烧结温度的钨酸钡（BaWO）粉末以及含有不同稀土（RE）激活离子（Dy、Sm、Tb）浓度的BaWO:Dy荧光粉样品。钨酸钡荧光粉的结构、形态和光致发光特性取决于稀土离子的浓度。利用X射线衍射（XRD）图谱分析了合成的BaWO的晶体学特征。基于场发射扫描电子显微镜（FE-SEM）测量的图像估计了晶体颗粒的尺寸和形状。随着BaWO颗粒的烧结温度从400℃升高到1000℃，颗粒尺寸逐渐增大并呈现出聚集在一起的趋势。在掺杂7 mol% Dy离子的样品中，所有发射带的强度都达到了最大值。通过在325 nm处激发，稀土掺杂的BaWO粉末的发射光谱由572、640和544 nm处的黄色（Dy）、红色（Sm+）和绿色（Tb）带组成。这表明大多数稀土离子在BaWO晶格中占据了没有反演对称性的位置。这些结果表明，通过适量稀土掺杂的基质可以实现荧光粉的强发射强度和可调颜色。此外，从水性胶体溶液中具有高透明度的荧光粉薄膜被沉积在纸币上，并考虑其是否适用于防伪应用。
