Shen Ji-Wei, Wang Zhiqing, Wei Xiaoxuan, Liu Jiawei, Wei Yinmao
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University Xi'an 710069 China
RSC Adv. 2018 Mar 6;8(18):9611-9617. doi: 10.1039/c8ra00655e. eCollection 2018 Mar 5.
Herein, user-friendly control of the synthesis of sub-10 nm hexagonal (β-) NaYbF:Er nanocrystals (NCs) with extremely low-level Gd doping (0%, 10 mol%) was achieved. We reveal for the first time that the effective sodium/fluoride levels during the formation of cubic (α-) nuclei are not only controlled by the sodium/fluoride to rare-earth precursor ratios used, but also sensitively restricted by the NaF generation reaction in a sodium oleate-based solvothermal system. Excessive NaF generation will lead to a respective sodium- and fluoride-deficient environment, delayed α-to-β transition and larger β-NCs. Based on these effects, sub-10 nm monodisperse low-level Gd-doped β-NaYbF:Er was obtained with a user-friendly low fluoride dosage by finely balancing this NaF generation reaction and achieving an intrinsic optimized sodium-fluoride level for NC nucleation. Notably, our work represents the first example where the focus is on the competing NaF generation reaction and its use for nucleation regulation, as well as for the user-friendly control of the solvothermal synthesis of sub-10 nm β-NaYbF:Er.
在此，实现了对亚10纳米六方（β-）NaYbF:Er纳米晶体（NCs）合成的用户友好型控制，其中钆（Gd）掺杂水平极低（0%，10摩尔%）。我们首次揭示，立方（α-）核形成过程中的有效钠/氟水平不仅受所用钠/氟与稀土前驱体比例的控制，还在油酸钠基溶剂热体系中受到NaF生成反应的敏感限制。过量的NaF生成会导致各自缺钠和缺氟的环境、α向β转变延迟以及更大的β-NCs。基于这些影响，通过精细平衡该NaF生成反应并实现用于NC成核的固有优化钠氟水平，以用户友好的低氟用量获得了亚10纳米单分散低水平Gd掺杂的β-NaYbF:Er。值得注意的是，我们的工作代表了首个专注于竞争性NaF生成反应及其用于成核调控以及用于亚10纳米β-NaYbF:Er溶剂热合成的用户友好型控制的实例。
