Sunitha D V, Nagabhushana H, Sharma S C, Nagabhushana B M, Daruka Prasad B, Chakradhar R P S
Prof. C.N.R.Rao Centre for Advanced Materials, Tumkur University, Tumkur 572 103, India.
Prof. C.N.R.Rao Centre for Advanced Materials, Tumkur University, Tumkur 572 103, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jun 5;127:381-7. doi: 10.1016/j.saa.2014.02.056. Epub 2014 Feb 26.
A series of Dy(3+) (1-5mol.%) activated Sr2SiO4 nanophosphors were prepared by low temperature solution combustion method using oxalyl dihydrazide (ODH) as a fuel. The obtained phosphor was well characterized by powder X-ray diffraction, scanning electron microscopy, and UV-visible spectroscopy. The average crystallite sizes were estimated by Debye-Scherrer formula and Williamson-Hall plots and found to be in the range 20-32nm. Energy band gap was found to be widened with increase of Dy(3+) ion dopant. Photoluminescence spectra consist of three main groups of peaks in 460-500nm (blue), 555-610nm (yellow) and 677nm (red) respectively. These peaks were assigned to transition of (4)F9/2→(6)H15/2,13/2,11/2. The critical distance between Dy(3+) ions and quenching site was found to be ∼16.71Ǻ. The chromaticity co-ordinates of all the prepared phosphors were located in white light; as a result Dy(3+) activated Sr2SiO4 is a promising single phased phosphor for white light emitting diodes. Thermoluminescence (TL) of Dy(3+) doped Sr2SiO4 nanophosphors were investigated using γ-irradiation in the dose range 1-6kGy at a warming rate of 2.5°Cs(-1). The phosphors show a well resolved single glow peak at ∼145°C. The kinetic parameters were estimated by different methods and the results discussed. The TL intensity increases linearly with γ-dose at room temperature. The effect of fading with storage time was found to be ∼66% which is highly useful in radiation dosimetry.
采用低温溶液燃烧法，以草酰二肼（ODH）为燃料制备了一系列Dy(3+)（1 - 5mol%）激活的Sr2SiO4纳米磷光体。通过粉末X射线衍射、扫描电子显微镜和紫外-可见光谱对所得磷光体进行了充分表征。利用Debye-Scherrer公式和Williamson-Hall图估算了平均微晶尺寸，发现其在20 - 32nm范围内。发现随着Dy(3+)离子掺杂剂的增加，能带隙变宽。光致发光光谱分别由460 - 500nm（蓝色）、555 - 610nm（黄色）和677nm（红色）的三组主要峰组成。这些峰归因于(4)F9/2→(6)H15/2,13/2,11/2的跃迁。发现Dy(3+)离子与猝灭位点之间的临界距离约为16.71Ǻ。所有制备的磷光体的色度坐标都位于白光区域；因此，Dy(3+)激活的Sr2SiO4是一种有前途的用于白光发光二极管的单相磷光体。使用γ射线在1 - 6kGy的剂量范围内、以2.5°C s(-1)的升温速率对Dy(3+)掺杂的Sr2SiO4纳米磷光体的热释光（TL）进行了研究。磷光体在约145°C处显示出一个分辨良好的单发光峰。通过不同方法估算了动力学参数并对结果进行了讨论。在室温下，TL强度随γ剂量线性增加。发现存储时间导致的衰减效应约为66%，这在辐射剂量测定中非常有用。
