Roles of oxygen vacancies and pH induced size changes on photo- and radioluminescence of undoped and Eu3+-doped La2Zr2O7 nanoparticles
Roles of oxygen vacancies and pH induced size changes on photo- and radioluminescence of undoped and Eu3+-doped La2Zr2O7 nanoparticles
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DOI：
10.1016/j.jlumin.2019.01.059
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发表时间：
2019-05
影响因子：
3.6
通讯作者：
S. Gupta;Maya Abdou;J. Zuniga;P. Ghosh;Enrique Molina;Ben Xu;M. Chipara;Yuanbing Mao
中科院分区：
文献类型：
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作者：
S. Gupta;Maya Abdou;J. Zuniga;P. Ghosh;Enrique Molina;Ben Xu;M. Chipara;Yuanbing Mao
缺陷、掺杂和粒径对纳米荧光粉的光学性能有重要影响。在这项研究中，未掺杂的La2Zr2O7纳米粒子（LZO）显示在紫外光照射下，由于在带隙中的离子化氧空位的存在下的发射。此外，我们还研究了La2Zr2O7：Eu3+（LZOE）纳米颗粒的粒径对其结构、比表面积、光致发光、辐射发光、寿命和量子产率的影响。随着共沉淀pH升高以制备用于熔融盐合成NP的单源前体，发光输出和量子产率逐渐降低。在X射线照射下，LZOE NP发出红光，凸显了其作为X射线闪烁体的潜力。我们解释了基于表面缺陷类比的实验观察。实验获得的紫蓝色和红色光学区域的发射与缺陷相关的发射。高的不对称率表明Eu3+离子在LZO基质中的对称性较低，Eu3+离子在LaO8位的占位比在ZrO6位的占位更有利。LZOE的发射光谱也显示出有利的主机掺杂剂（Eu 3+）的能量转移。本工作为制备高效的红色荧光粉和X射线闪烁体在光电子学和X射线诱导治疗诊断学中的应用提供了清晰的图像。
Defect, doping and particle size play important roles on the optical performance of nanophosphors. In this study, undoped La2Zr2O7NPs (LZO) displayed multicolor emission under UV irradiation due to the presence of ionized oxygen vacancies in the band gap. In addition, we explored the effect of particle size of La2Zr2O7:Eu3+(LZOE) NPs on their structure, surface area, photoluminescence, radioluminescence, lifetime and quantum yield. There is progressive decrease in luminescence output and quantum yield as the coprecipitation pH is raised to prepare the single-source precursors for the molten salt synthesis of the NPs. Under X-ray irradiation, the LZOE NPs emit red light highlighting their potential as X-ray scintillator. We explained the experimental observations based on surface defect analogy. The experimentally obtained emission in violet-blue and red optical regions is correlated to defect related emission. High asymmetry ratio suggested low symmetric environment of Eu3+ions in the LZO host and the occupancy of Eu3+ions is more favorable at LaO8site compared to ZrO6site. Emission spectra of the LZOE also showed favorable host to dopant (Eu3+) energy transfer. This work provides a clear picture of making highly efficient red phosphor and X-ray scintillator for applications in optoelectronics and X-ray induced theranostics.