ABSTRACT According to the spectra of stationary X-ray excited luminescence (XEL) of BaF2: Eu nanophosphors at 80 and 294 K, it was revealed that the thermal annealing of fine-grained nanoparticles (d = 35 nm) in the range of 400–1000°C, which is accompanied by an increase of their sizes in the range of 58–120 nm, does not result in effective changes of the charge state of Eu3 + → Eu2 + activator, in contrast to CaF2: Eu nanoparticles. The maximum light output of X-ray excited luminescence of BaF2: Eu nanophosphors in the 590 nm emission band of Eu3+ ion was observed at an annealing temperature of 600°C with the average size of nanoparticles 67 nm. The subsequent growth of annealing temperatures, especially in the range of 800–1000°C, causes decrease in the light output of X-ray excited luminescence due to the increase of defect concentration in the lattice as a result of sharp increase of nanoparticle sizes and their agglomeration. In BaF2: Eu nanoparticles of 58 nm size, according to the thermostimulated luminescence (TSL) spectrum, transformation of Eu3+ → Eu2+ under the influence of long-time X-ray irradiation was revealed for the peak of 151 K. Thus, X-ray excited luminescence spectra of BaF2: Eu nanophosphors are formed predominantly due to the emission of Eu3+ ions, while emission of Eu2+ ions is observed in the TSL spectra.

中文翻译：

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BaF2 中活化剂的电荷态和尺寸效应：Eu 纳米磷光体

摘要 根据 BaF2: Eu 纳米荧光粉在 80 和 294 K 的固定 X 射线激发发光 (XEL) 光谱，发现细粒纳米粒子 (d = 35 nm) 在 400–与 CaF2: Eu 纳米颗粒相比，1000°C 伴随着它们尺寸在 58-120 nm 范围内的增加，不会导致 Eu3 + → Eu2 + 活化剂的电荷状态发生有效变化。BaF2:Eu 纳米磷光体在 Eu3+ 离子 590 nm 发射带的 X 射线激发发光的最大光输出在 600°C 的退火温度下观察到，纳米粒子的平均尺寸为 67 nm。随后退火温度的增长，尤其是在 800-1000°C 的范围内，由于纳米颗粒尺寸急剧增加及其团聚导致晶格中缺陷浓度的增加，导致 X 射线激发发光的光输出降低。在 BaF2: Eu 纳米粒子 58 nm 大小，根据热刺激发光 (TSL) 光谱，显示 Eu3+ → Eu2+ 在长时间 X 射线照射影响下的转变为 151 K。因此，X 射线BaF2 的激发发光光谱：Eu 纳米磷光体主要由于 Eu3+ 离子的发射而形成，而 Eu2+ 离子的发射在 TSL 光谱中观察到。