School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798.
ACS Appl Mater Interfaces. 2011 Nov;3(11):4431-6. doi: 10.1021/am2012118. Epub 2011 Nov 1.
Solid-state reaction is the most common method for preparing luminescent materials. However, the luminescent dopants in the hosts tend to aggregate in the high-temperature annealing process, which causes adverse effect in photoluminescence. Herein, we report a novel europium (II)-doped zeolite derivative prepared by a combined ion-exchange and solid-state reaction method, in which the europium (II) ions are isolated to a large extent by the micropores of the zeolite. Excited by a broad ultraviolet band from 250 to 420 nm, a strong blue emission peaking at 450 nm was observed for these Eu-embedded zeolites annealed at 800 °C in a reducing atmosphere. The zeolite host with pores of molecular dimension was found to be an excellent host to isolate and stabilize the Eu(2+) ions. The as-obtained europium (II)-doped zeolite derivative showed an approximately 9 fold enhancement in blue emission compared to that of the general europium (II)-doped aluminosilicates obtained by conventional solid-state reaction, indicating that, by isolating active luminescence centers, it is promising to achieve highly luminescent materials. Also, the strong blue emission with broad UV excitation band suggests a potential candidate of phosphor for ultraviolet excited light-emitting diode.
固态反应是制备发光材料最常用的方法。然而，发光掺杂剂在高温退火过程中往往会聚集，这会对光致发光产生不利影响。在此，我们报告了一种通过离子交换和固态反应相结合的方法制备的新型铕（II）掺杂沸石衍生物，其中铕（II）离子在很大程度上被沸石的微孔隔离。在还原气氛中 800°C 退火后，这些嵌入铕的沸石在 250 到 420nm 的宽紫外带激发下，观察到强烈的 450nm 处的蓝色发射峰。具有分子尺寸孔的沸石主体被发现是一种极好的主体，可用于隔离和稳定 Eu(2+)离子。与通过传统固态反应获得的一般铕（II）掺杂铝硅酸盐相比，所获得的铕（II）掺杂沸石衍生物的蓝色发射强度提高了约 9 倍，这表明通过隔离活性发光中心，可以实现高发光材料。此外，具有宽紫外激发带的强蓝色发射表明其可能是一种用于紫外光激发发光二极管的荧光粉候选材料。
