We present the thermal stability and the photoluminescence properties of RE-doped (RE = Ho, Er, Tm) alumina nanoparticles in the phase system Al₂O₃-SiO₂ with respect to the chemical composition and the thermal processing conditions applied in the fiber-optic technology. The alumina and silica soot reacted together to form mullite when the Al₂O₃ concentration was higher than 5 mol. %. We have demonstrated that the solubility limits of RE ions in the mullite nanocrystals are strongly limited. The RE ions preferentially occupy highly disordered positions on the nanoparticle surface or in the amorphous Al³⁺-enriched shell around the nanoparticles, exhibiting maximal lifetime of approx. 1.2 ms, 10.0 ms and 0.6 ms in the Ho-, Er- and Tm-doped samples. Rapid cooling of the samples with stoichiometric composition 3Al₂O₃·2SiO₂ managed to prepare highly defective mullite nanocrystals with embedded RE ions, exhibiting promising photoluminescence lifetimes of 5.6 ms and 2.4 ms in the case of Ho³⁺ and Tm³⁺ ions, respectively. In optical fibers with 5 mol. % Al₂O₃, the formation of amorphous Al³⁺-enriched nanoparticles was observed and the photoluminescence lifetime was in a good agreement with corresponding bulk samples. Exploitation of the RE-doped stoichiometric mullite in the fiber-optic technology may be a perspective way to improve the photoluminescence efficiency of active optical fibers for high-power applications.

我们介绍了相体系 Al ₂ O ₃ -SiO ₂中稀土掺杂（RE = Ho、Er、Tm）氧化铝纳米粒子的热稳定性和光致发光特性，涉及纤维中应用的化学成分和热处理条件-光学技术。当Al ₂ O ₃浓度高于5mol时，氧化铝和二氧化硅烟灰一起反应形成莫来石。%。我们已经证明，莫来石纳米晶体中稀土离子的溶解度极限受到很大限制。RE离子优先占据纳米颗粒表面或非晶Al ^{3+ 中}高度无序的位置- 纳米颗粒周围的富集壳，最大寿命约为。Ho、Er 和 Tm 掺杂样品中的 1.2 ms、10.0 ms 和 0.6 ms。具有化学计量组成的 3Al ₂ O ₃ ·2SiO ₂样品的快速冷却设法制备了具有嵌入 RE 离子的高缺陷莫来石纳米晶体，在 Ho ³⁺和 Tm ³⁺离子的情况下表现出有希望的光致发光寿命为 5.6 ms 和 2.4 ms ，分别。在光纤中含有 5 mol。% Al ₂ O ₃，形成非晶Al ³⁺观察到富集的纳米颗粒，并且光致发光寿命与相应的大块样品非常吻合。在光纤技术中利用掺稀土的化学计量莫来石可能是提高有源光纤在高功率应用中的光致发光效率的一种有前景的方法。