Raju G Seeta Rama, Pavitra E, Nagaraju Goli, Yu Jae Su
Department of Electronics and Radio Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
Dalton Trans. 2015 Jan 28;44(4):1790-9. doi: 10.1039/c4dt03181d.
Red color-emitting CaGd2ZnO5:Eu(3+) (CGZO:Eu(3+)) nanophosphors were synthesized by a facile sol-gel process. The structural and luminescent properties of these phosphors were investigated as a function of annealing temperature and Eu(3+) ion concentration. The orthorhombic phase was confirmed at different annealing temperatures, showing an irregular morphology within the nanoscale range. Photoluminescence (PL) excitation spectra of CGZO:Eu(3+) showed host absorption band (HAB), charge transfer band (CTB), and intense f-f transitions of Eu(3+) in the violet and blue wavelength regions. The CTB intensity increased and the HAB intensity decreased with increasing annealing temperature or Eu(3+) ion concentration. The CGZO:Eu(3+) exhibited a strong absorption in the blue region as compared to the CTB and had a superior property compared to available commercial phosphors. This feature facilitates the fabrication of high color rendering index white light-emitting diodes for display systems. In PL spectra, an intense red emission was observed due to the hypersensitive (5)D0→(7)F2 transition with good asymmetry ratio and chromaticity coordinates. Optimized annealing temperature and concentration of Eu(3+) ions were observed for CGZO host lattice based on the 466 nm excitation wavelength. The cathodoluminescent properties were also similar to the PL results.
通过简便的溶胶 - 凝胶法合成了发红光的CaGd2ZnO5:Eu(3+)（CGZO:Eu(3+)）纳米磷光体。研究了这些磷光体的结构和发光性质随退火温度和Eu(3+)离子浓度的变化。在不同退火温度下证实了正交相，在纳米尺度范围内呈现出不规则形态。CGZO:Eu(3+)的光致发光（PL）激发光谱在紫外和蓝光波长区域显示出基质吸收带（HAB）、电荷转移带（CTB）以及Eu(3+)的强烈f-f跃迁。随着退火温度或Eu(3+)离子浓度的增加，CTB强度增加而HAB强度降低。与CTB相比，CGZO:Eu(3+)在蓝光区域表现出强烈吸收，并且与市售磷光体相比具有优异性能。这一特性有助于制造用于显示系统的高显色指数白光发光二极管。在PL光谱中，由于超灵敏的(5)D0→(7)F2跃迁，观察到强烈的红色发射，具有良好的不对称比和色度坐标。基于466nm激发波长，观察到了CGZO主体晶格的优化退火温度和Eu(3+)离子浓度。阴极发光性质也与PL结果相似。
