Shape controlled iron oxide nanoparticles: inducing branching and controlling particle crystallinity
Shape controlled iron oxide nanoparticles: inducing branching and controlling particle crystallinity
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DOI：
10.1039/d0ce01291b
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发表时间：
2021-01-21
期刊：
影响因子：
3.1
通讯作者：
Nguyen Thi Kim Thanh
中科院分区：
文献类型：
--
作者：
AbuTalib, Nur Hanisah;LaGrow, Alec P.;Nguyen Thi Kim Thanh
各向异性纳米粒子在催化、磁学和生物医学等领域的应用引起了人们的广泛关注。然而，生长这种纳米颗粒的合成策略仍然有限，因为它们的生长机制知之甚少。本工作提出了基于乙酰丙酮铁（m）在有机溶剂中分解以形成支化或多支化的各向异性的氧化铁纳米颗粒（IONP）的合成。我们充分探索其生长参数，以了解不同量的油胺（OAM），以及氮气吹扫对颗粒形态的影响。在这里，我们显示了广泛的尺寸和形状的IONP是各向同性和各向异性之间的合成关系。在所有参数中，反应中油胺的量是调节粒度的关键，而合成期间氮气吹扫的效果显示对于支化和多支化NP的形成至关重要。两个多支化NP系统，只有一个小的差异，在合成条件被证明具有根本不同的磁性能，如在交变磁场加热。这是由于在一个结构中发现的缺陷而不是在另一个结构中发现的缺陷。通过跟踪它们在生长过程中的发展，在反应的早期阶段在两个系统中观察到晶体缺陷。然而，对于变成单晶的多分支结构，核的聚集在反应中发生得更早，允许更多的时间生长和微晶重排发生。这些结果对于控制具有相似结构的各向异性纳米材料的性质具有广泛的意义，包括它们的磁性行为。
Anisotropic nanoparticles (NPs) have garnered a great deal of attention for their applications in catalysis, magnetism and biomedicine. However, synthetic strategies to grow such NPs are still limited as their growth mechanisms are poorly understood. This work presents the synthesis of iron oxide nanoparticles (IONPs) based on the decomposition of iron(m) acetylacetonate in organic solvents to form anisotropic IONPs that are branched or multiply branched. We fully explore their growth parameters to understand the effect of varying amounts of oleylamine (OAm), as well as a nitrogen purge on particle morphology. We show here the synthetic relationship between a wide range of sizes and shapes of IONPs that are both isotropic and anisotropic. Of all the parameters, the amount of oleylamine in the reaction is the key to tune the particle size while the effect of a nitrogen gas purge during synthesis was shown to be crucial for the formation of the branched and multiply branched NPs. Two multiply branched NP systems with only a small difference in the synthetic conditions were shown to have radically different magnetic properties, such as heating in an alternating magnetic field. This was attributed to the defects found in the structure of one and not in the other. By following their development during growth, crystal defects were observed in both systems during the early stages of the reaction. However, for the multiply branched structure that became single crystalline, the aggregation of the nuclei occurred earlier in the reaction, allowing more time for growth and crystallite rearrangement to occur. These results have wide ranging implications for controlling the properties of anisotropic nanomaterials with similar structures, including their magnetic behavior.