Jiménez José A, Sendova Mariana
Department of Chemistry & Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, United States.
Optical Spectroscopy & Nano-Materials Lab, New College of Florida, Sarasota, Florida 34243, United States.
J Phys Chem B. 2023 Mar 30;127(12):2818-2828. doi: 10.1021/acs.jpcb.2c08400. Epub 2023 Mar 20.
Phosphate glasses incorporating large concentrations of Eu ions are of interest for optical applications as their distinct red-emitting character resists deterioration with increasing Eu content. Still, the low propensity for concentration quenching in these is not well understood, and thus evaluations linking structural, thermal, and optical properties with Eu content are desired. In this work, 50PO-(50 - )BaO-EuO ( = 0, 1, 2, 4, 6 mol %) glasses pertinent to photonics were prepared by melt-quenching and further scrutinized with regards to the composition-structure-property relationship. A comprehensive experimental investigation was carried out encompassing density and basic physical properties, X-ray diffraction (XRD), Raman scattering, dilatometry, differential scanning calorimetry (DSC), optical absorption, and photoluminescence (PL) spectroscopy with emission decay analysis. The data from six techniques are in strong agreement with the existence of a critical EuO concentration which divides the studied concentration range into two sections: (1) lower concentrations, up to about 2.5 (±0.1) mol %, with predominantly long-range (LR) effects of the modifier electrostatic field and (2) higher dopant concentrations, with predominantly short-range (SR) effects of the modifier field. The authors propose that LR interactions lead to shortening of the P-tetrahedral chains, while the SR interactions are expressed in increasing the covalent character of the bonds between the nonbridging oxygens and Eu ions. Concentration correlations between diverse macroscopic data sets, such as densitometry, dilatometry, Raman scattering, calorimetry, and PL, concur synergistically, elucidating the microscopic physical LR-SR interplay between glass network former and the cationic electrostatic field of the modifiers.
含有高浓度铕离子的磷酸盐玻璃因其独特的红色发光特性，随着铕含量增加而不易劣化，在光学应用方面备受关注。然而，这些玻璃中浓度猝灭倾向较低的原因尚未得到很好的理解，因此需要对结构、热学和光学性质与铕含量之间的关系进行评估。在这项工作中，通过熔体淬火制备了与光子学相关的50PO-(50 - )BaO-EuO（ = 0、1、2、4、6摩尔%）玻璃，并进一步研究了其组成-结构-性能关系。开展了一项全面的实验研究，涵盖密度和基本物理性质、X射线衍射（XRD）、拉曼散射、热膨胀法、差示扫描量热法（DSC）、光吸收以及发射衰减分析的光致发光（PL）光谱。六种技术的数据与临界EuO浓度的存在高度一致，该临界浓度将研究的浓度范围分为两个部分：（1）较低浓度，高达约2.5（±0.1）摩尔%，主要是改性剂静电场的长程（LR）效应；（2）较高的掺杂剂浓度，主要是改性剂场的短程（SR）效应。作者提出，LR相互作用导致P-四面体链缩短，而SR相互作用表现为非桥氧与铕离子之间键的共价性增加。不同宏观数据集（如密度测定、热膨胀测定、拉曼散射、量热法和PL）之间的浓度相关性协同一致，阐明了玻璃网络形成体与改性剂阳离子静电场之间微观物理LR-SR相互作用。
