Pressure-induced site swapping, luminescence quenching, and color tunability of Gd2Hf2O7:Eu3+ nanoparticles
Pressure-induced site swapping, luminescence quenching, and color tunability of Gd2Hf2O7:Eu3+ nanoparticles
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DOI：
10.1016/j.optmat.2020.110789
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发表时间：
2021-02
影响因子：
3.9
通讯作者：
S. Gupta;Hisham Abdou;Yuanbing Mao
中科院分区：
文献类型：
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作者：
S. Gupta;Hisham Abdou;Yuanbing Mao
高压（HP）研究一直是基础物理学中的一个活跃的研究领域，并满足多种技术应用的需求。本文研究了高压对焦绿石Gd_2Hf_2O_7：5%Eu ~（3+）纳米颗粒光学性质的影响。我们研究了它们在高压下的光学性质，如电荷转移跃迁、发射动力学、不对称比、激发态寿命和色坐标。HP光致发光（PL）光谱表明，由于GHOE NP中O2−离子周围的电荷密度降低，电荷转移在~5.4 GPa（高达53 GPa）以上不可逆且完全消失。由于缺陷密度和交叉弛豫的增加，高压导致5D 1/5D2态的发射峰展宽，5D 0 → 7 F2红光发射强度降低。此外，有系统的降低不对称比，这表明提高对称性周围的Eu 3+离子和Eu-O键的共价还原。PL寿命谱表明，大部分的Eu 3+离子是本地化的Gd 3+网站在较低的压力和相同的变化，对称的Hf 4+网站随着压力的增加。颜色坐标值表示它们在红-橙-黄域中的压力诱导的颜色可调性。因此，我们证明了压力诱导的位点交换，发光猝灭，Eu-O共价变化，和颜色的可调谐性的GHOE纳米粒子的光学材料的高压研究。
High-pressure (HP) studies have been an active research area in fundamental physics and to meet demand of several technological applications. In this paper, we have explored the HP effect on optical properties of pyrochlore Gd2Hf2O7:5%Eu3+(GHOE) nanoparticles (NPs). We have investigated several aspects of their optical properties under HP such as charge transfer transitions, emission dynamics, asymmetry ratio, excited state lifetime, and color coordinates. HP photoluminescence (PL) spectra indicate the irreversible and complete disappearance of charge transfer beyond ~5.4 GPa (up to 53 GPa) owing to the reduced charge density around O2−ion in the GHOE NPs. Elevated pressure induces peak broadening, evolution of emission from5D1/5D2states, and reduction of5D0→7F2red emission intensity due to enhanced defect density and cross relaxation. Moreover, there is systematic reduction in asymmetry ratio which suggests improving symmetry around Eu3+ion and covalency reduction of Eu–O bond. PL lifetime spectroscopy suggests that a large fraction of Eu3+ions is localized at Gd3+site at lower pressure and the same changes to symmetric Hf4+site with increasing pressure. Color coordinate value indicates their pressure induced color tunability in the red-orange-yellow domain. Hence, we demonstrated pressure induced site swapping, luminescence quenching, Eu–O covalency change, and color tunability of the GHOE NPs for high pressure research on optical materials.