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UV emitting Gd incorporated LiBaB9O15 phosphors: An ESR and photoluminescence investigation
Journal of Luminescence ( IF 3.3 ) Pub Date : 2020-07-01 , DOI: 10.1016/j.jlumin.2020.117239
N. Singh , Jung-Kul Lee , M. Mohapatra , R.M. Kadam , Vijay Singh

Abstract An effort was made to get an idea regarding the correlation between structure and radiative properties of Gd incorporated LiBaB9O15 matrix. The samples were synthesized via a combustion route and characterized using X-ray diffraction (XRD). Photoluminescence (PL) experiments were carried out in order to understand the radiative properties and local site symmetry of ‘Gd’ ions in the sample. The site occupancy of the rare earth ions were also evaluated through electron spin resonance (ESR) measurements. The PL data suggested the emanation of UV light from the system with emission maxima at 307 and 311 nm. Both these peaks belong to the UV-B region which has many useful applications in phototherapy. The nature of the peaks suggested the stabilization of the ion predominantly in asymmetric geometry making the electric dipole transitions more prominent. It was observed that the maximum radiative or luminescence intensity could be obtained for the 0.048 mol ‘Gd’ doped sample. Beyond this, concentration quenching reduced the PL intensity. Based on the energy transfer model it was evaluated that ‘Foster’ type mechanism was responsible for the observed concentration quenching. From the ESR data it could be inferred that the rare earth ion stabilises at two different sites with differing geometries. At lower doping levels, it was seen that the Gd3+ ions predominantly existed at relatively more distorted Ba2+ sites and at higher concentrations, the ions are at the distorted sites as well as at Ba2+ sites with less distorted environment.

中文翻译:

掺入 LiBaB9O15 磷光体的紫外发光 Gd:ESR 和光致发光研究

摘要 试图了解 Gd 掺入 LiBaB9O15 矩阵的结构和辐射特性之间的相关性。样品通过燃烧途径合成,并使用 X 射线衍射 (XRD) 进行表征。进行光致发光 (PL) 实验以了解样品中“Gd”离子的辐射特性和局部位置对称性。还通过电子自旋共振 (ESR) 测量评估了稀土离子的位点占有率。PL 数据表明系统发出紫外光,最大发射波长为 307 和 311 nm。这两个峰都属于 UV-B 区域,在光疗中有许多有用的应用。峰的性质表明离子主要在不对称几何形状中稳定,使得电偶极跃迁更加突出。据观察,对于 0.048 mol 'Gd' 掺杂的样品可以获得最大的辐射或发光强度。除此之外,浓度猝灭降低了 PL 强度。基于能量转移模型,评估了“福斯特”型机制是造成观察到的浓度猝灭的原因。从 ESR 数据可以推断,稀土离子稳定在具有不同几何形状的两个不同位置。在较低的掺杂水平下,可以看出 Gd3+ 离子主要存在于相对更扭曲的 Ba2+ 位点,在较高浓度下,离子位于扭曲位点以及环境扭曲较小的 Ba2+ 位点。据观察,对于 0.048 mol 'Gd' 掺杂的样品可以获得最大的辐射或发光强度。除此之外,浓度猝灭降低了 PL 强度。基于能量转移模型,评估了“福斯特”型机制是造成观察到的浓度猝灭的原因。从 ESR 数据可以推断,稀土离子稳定在具有不同几何形状的两个不同位置。在较低的掺杂水平下,可以看出 Gd3+ 离子主要存在于相对更扭曲的 Ba2+ 位点,在较高浓度下,离子位于扭曲位点以及环境扭曲较小的 Ba2+ 位点。据观察,对于 0.048 mol 'Gd' 掺杂的样品可以获得最大的辐射或发光强度。除此之外,浓度猝灭降低了 PL 强度。基于能量转移模型,评估了“福斯特”型机制是造成观察到的浓度猝灭的原因。从 ESR 数据可以推断,稀土离子稳定在具有不同几何形状的两个不同位置。在较低的掺杂水平下,可以看出 Gd3+ 离子主要存在于相对更扭曲的 Ba2+ 位点,在较高浓度下,离子位于扭曲位点以及环境扭曲较小的 Ba2+ 位点。浓度猝灭降低了PL强度。基于能量转移模型,评估了“福斯特”型机制是造成观察到的浓度猝灭的原因。从 ESR 数据可以推断,稀土离子稳定在具有不同几何形状的两个不同位置。在较低的掺杂水平下,可以看出 Gd3+ 离子主要存在于相对更扭曲的 Ba2+ 位点,在较高浓度下,离子位于扭曲位点以及环境扭曲较小的 Ba2+ 位点。浓度猝灭降低了PL强度。基于能量转移模型,评估了“福斯特”型机制是造成观察到的浓度猝灭的原因。从 ESR 数据可以推断,稀土离子稳定在具有不同几何形状的两个不同位置。在较低的掺杂水平下,可以看出 Gd3+ 离子主要存在于相对更扭曲的 Ba2+ 位点,在较高浓度下,离子位于扭曲位点以及环境扭曲较小的 Ba2+ 位点。
更新日期:2020-07-01
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