Facile synthesis and upconversion luminescence of beta-NaYF4:Yb, Tm nanocrystals with highly tunable and uniform beta-NaYF4 shells
Facile synthesis and upconversion luminescence of beta-NaYF4:Yb, Tm nanocrystals with highly tunable and uniform beta-NaYF4 shells
复制标题
具有高度可调且均匀的 β-NaYF4 壳的 β-NaYF4:Yb、Tm 纳米晶体的简便合成和上转换发光
DOI：
10.1016/j.jallcom.2016.04.302
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发表时间：
2016
影响因子：
6.2
通讯作者：
Cao Wenwu
中科院分区：
文献类型：
--
作者：
Liu Lixin;Qin Feng;Zhao Hua;Lv Tianquan;Zhang Zhiguo;Cao Wenwu
采用一步晶种介导法合成了具有高度可调和均匀厚度壳层的均匀核壳纳米晶。结果表明，配体油酸（OA）的量直接影响壳前驱体在核纳米碳上外延生长的均匀性。实验确定了配体OA的最佳用量。在此基础上，合成了壳层厚度分别为1 nm、3 nm、5 nm、10 nm和15 nm的NaYF 4：Yb，Tm/NaYF 4核壳纳米晶。TEM和EDS分析证实了具有上述规格的核-壳NC的成功合成。在980 nm激发下，核-壳NC的上转换（UC）荧光强度随着壳厚度（d）以（1 - 0.9exp（-d/d 0））的形式指数增强。对于我们的核-壳纳米粒子的800 nm发射强度，d 0被确定为约5.8 nm，对应于约13倍的增强。当壳层厚度大于0时，UC荧光强度的增加变得相当缓慢。
Homogeneous core-shell nanocrystals (NCs) with highly tunable and uniform thickness shells were synthesized with a one-step, seed-mediated process. It was determined that the quantity of ligand oleic acid (OA) directly affects the uniformity of shell precursor epitaxial growth on core NCs. The optimum quantity of ligand OA was experimentally determined. Based on this finding, NaYF4:Yb, Tm/NaYF4core-shell NCs with shell thicknesses tuned to 1 nm, 3 nm, 5 nm, 10 nm, and 15 nm were synthesized. TEM and EDS analysis confirmed the successful synthesis of core-shell NCs with the aforementioned specifications. Under 980 nm excitation, the upconversion (UC) fluorescence intensity of the core-shell NCs is enhanced exponentially with shell thickness (d) in the form of (1−0.9exp (−d/d0)). For the 800 nm emission intensity of our core-shell NCs, thed0was determined as about 5.8 nm, corresponding to an enhancement of about 13 times. When the shell thickness is beyondd0, the UC fluorescence intensity increase becomes quite slow.