Seeta Rama Raju G, Pavitra E, Yu Jae Su
Department of Electronics and Radio Engineering, Institute for Laser Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
Dalton Trans. 2014 Jul 7;43(25):9766-76. doi: 10.1039/c4dt00656a.
Tm(3+), Er(3+), Tm(3+)/Er(3+), Tm(3+)/Er(3+)/Eu(3+) single, double and triple activator ion/ions doped nanocrystalline BaGd2O4 (BG) phosphors were prepared by a Pechini type sol-gel process. After annealing at 1300 °C, X-ray diffraction patterns confirmed their orthorhombic structure. Field-emission transmission electron microscope images of the BG sample indicated a nanoneedle-type morphology. Photoluminescence (PL) and cathodoluminescence (CL) measurements were utilized to establish the emission properties of rare-earth ions doped nanocrystalline BG host lattice. Under near-ultraviolet (NUV) excitations, BG:Tm(3+) and BG:Er(3+) exhibited their characteristic emissions in the blue and green regions, respectively, while BG:Tm(3+)/Er(3+) and BG:Tm(3+)/Er(3+)/Eu(3+) showed cyan and white light emissions, respectively, when doped with appropriate amounts of activator ions. In the PL, the cross-relaxation process is dominant rather than the energy transfer process. Due to the different mechanism from PL, the CL spectra showed different emission features of BG:Tm(3+)/Er(3+)/Eu(3+) phosphor. The CL spectra of BG:Tm(3+) and BG:Er(3+) established the high purity blue and green emissions, respectively. From the PL and CL investigations, the white-light emission was realized from the single-phase BG:Tm(3+)/Er(3+)/Eu(3+) phosphor under NUV and low voltage electron beam excitations.
通过佩琴尼型溶胶 - 凝胶法制备了Tm(3+)、Er(3+)、Tm(3+)/Er(3+)、Tm(3+)/Er(3+)/Eu(3+)单、双和三激活离子掺杂的纳米晶BaGd2O4（BG）荧光粉。在1300℃退火后，X射线衍射图谱证实了它们的正交结构。BG样品的场发射透射电子显微镜图像显示出纳米针状形态。利用光致发光（PL）和阴极发光（CL）测量来确定稀土离子掺杂的纳米晶BG主体晶格的发射特性。在近紫外（NUV）激发下，BG:Tm(3+)和BG:Er(3+)分别在蓝色和绿色区域表现出其特征发射，而当掺杂适量的激活离子时，BG:Tm(3+)/Er(3+)和BG:Tm(3+)/Er(3+)/Eu(3+)分别显示出青色和白色发光。在PL中，交叉弛豫过程占主导，而不是能量转移过程。由于与PL的机制不同，CL光谱显示了BG:Tm(3+)/Er(3+)/Eu(3+)荧光粉的不同发射特征。BG:Tm(3+)和BG:Er(3+)的CL光谱分别确定了高纯度的蓝色和绿色发射。通过PL和CL研究，在NUV和低电压电子束激发下，从单相BG:Tm(3+)/Er(3+)/Eu(3+)荧光粉实现了白光发射。
