N J Shivaramu, B N Lakshminarasappa, K R Nagabhushana, H C Swart, Fouran Singh
Department of Physics, University of the Free State, Bloemfontein ZA-9300, South Africa.
Department of Physics, Bangalore University, Bangalore 560 056, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Jan 15;189:349-356. doi: 10.1016/j.saa.2017.07.070. Epub 2017 Aug 1.
Nanocrystalline Er doped YOcrystals were prepared by a sol gel technique. X-ray diffraction (XRD) patterns showed the cubic structure of YO and the crystallite size was found to be ~25nm. Optical absorption showed absorption peaks at 454, 495 and 521nm. These peaks are attributed to the F+F, F and H+S transitions of Er. Under excitation at 378nm, the appearance of strong green (520-565nm) down conversion emission assigned to the (HS)→I transition and the feeble red (650-665nm) emission is assigned to the F→I transition. The color chromaticity coordinates showed emission in the green region. The strong green emission of YO:Er nanophosphor may be useful for applications in solid compact laser devices. Thermoluminescence (TL) studies of γ-irradiated YO:Er showed a prominent TL glow peak maximum at 383K along with a less intense shoulder peak at ~425K and a weak glow at 598K. TL emission peaks with maxima at 545, 490, 588 and 622nm for the doped sample were observed at a temperature of 383K and these emissions were due to defect related to the host material. TL kinetic parameters were calculated by a glow curve deconvolution (GCD) method and the obtained results are discussed in detail for their possible usage in high dose dosimetry.
采用溶胶 - 凝胶技术制备了掺铒纳米晶YO晶体。X射线衍射（XRD）图谱显示YO为立方结构，微晶尺寸约为25nm。光吸收在454、495和521nm处显示吸收峰。这些峰归因于铒的F + F、F和H + S跃迁。在378nm激发下，出现了归因于(HS)→I跃迁的强绿色（520 - 565nm）下转换发射和归因于F→I跃迁的微弱红色（650 - 665nm）发射。色度坐标显示发射位于绿色区域。YO:Er纳米磷光体的强绿色发射可能对固体紧凑型激光器件的应用有用。γ辐照的YO:Er的热释光（TL）研究表明，在383K处有一个突出的TL发光峰最大值，在约425K处有一个强度较低的肩峰，在598K处有一个微弱发光。在383K温度下观察到掺杂样品的TL发射峰最大值分别在545、490、588和622nm，这些发射归因于与主体材料相关的缺陷。通过发光曲线去卷积（GCD）方法计算了TL动力学参数，并详细讨论了所得结果在高剂量剂量测定中的可能用途。
