Kumar Mishra Neeraj, Upadhyay Madan M, Kumar Santosh, Kumar Kaushal
Optical Materials & Bio-imaging Research Laboratory, Department of Physics, Indian Institute of Technology (Indian School of Mines), Dhanabad 826004, India.
Department of Applied Science, IEC College of Engineering and Technology, Greater Noida 201308, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Dec 5;282:121664. doi: 10.1016/j.saa.2022.121664. Epub 2022 Jul 26.
By utilizing the effective energy transfer from Ce to Yb, Er and from Yb to Er authors have achieved dual mode emission in YAlGaO activated with Ce/Yb/Er ions. Surface morphological and elemental compositions of the prepared samples have been examined using field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS) analysis, respectively. The chemical state of the dopant ions is confirmed by the X-ray photoelectron spectroscopy (XPS). On excitation with 438 nm the prepared material has shown broad visible emission band around 511 nm due to the electronic transition of Ce ion. In addition to this sample has also shown NIR emission bands centered around 1024 nm and 1480 nm from Yb and Er ions, respectively. The emission band at 1024 nm could be due to the quantum cutting (QC) process. Furthermore, up-conversion (UC) emission against temperature and laser power variations is studied on 980 nm excitation wavelength. The prepared sample is used to fabricate visible and NIR LED devices by coating of sample on blue LED chip. Along with this demonstration, optical thermometry ability of the material is studied using emission intensity ratio of two emitting levels. Studies suggest that the prepared material could be useful as dual mode emitting phosphor and LED.
通过利用从铈（Ce）到镱（Yb）、铒（Er）以及从镱到铒的有效能量转移，作者在Ce/Yb/Er离子激活的YAlGaO中实现了双模式发射。分别使用场发射扫描电子显微镜（FE-SEM）和能量色散光谱（EDS）分析对制备样品的表面形态和元素组成进行了检测。通过X射线光电子能谱（XPS）确定了掺杂离子的化学状态。在438nm激发下，由于Ce离子的电子跃迁，制备的材料在511nm左右显示出宽的可见发射带。除此之外，样品还分别在1024nm和1480nm左右显示出来自Yb和Er离子的近红外发射带。1024nm处的发射带可能归因于量子剪裁（QC）过程。此外，在980nm激发波长下研究了上转换（UC）发射随温度和激光功率的变化。通过将样品涂覆在蓝色LED芯片上，制备的样品被用于制造可见光和近红外LED器件。除了这个演示之外，还利用两个发射能级的发射强度比研究了该材料的光学测温能力。研究表明，制备的材料可作为双模式发射荧光粉和LED。
