Ningbo Institute of Material Technology & Engineering-NIMTE, Chinese Academy of Sciences-CAS, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, NIMTE, CAS, Ningbo 315201, People's Republic of China.
Nanoscale. 2013 Mar 21;5(6):2454-9. doi: 10.1039/c3nr33602f.
By using Fe(CO)x-OAm (oleylamine, x < 5) as the Fe precursor to slow down the formation rate of FePt nanoparticles (NPs), a time dependence of the NPs' nucleation and growth process was observed by transmission electron microscopy (TEM). The complexing temperature of OAm and Fe(CO)5 at which Fe(CO)x-OAm was formed has a strong influence on the nucleation rate and growth process of the NPs. TEM analyses indicated that the NPs with isotropic shape were single crystalline throughout the synthesis and were formed by a diffusion-controlled Ostwald-ripening (OR) growth mechanism. The nanorod particles were first formed via joining of arbitrarily oriented single crystals and the two crystals formed a uniform particle afterwards, as described by the oriented-attachment (OA) mechanism. The ratio of OAm to Fe(CO)5 used in the preparation of Fe(CO)x-OAm has a significant influence on the growth process, and subsequently the shape, size and size distribution of the FePt NPs. By adjusting the ratio and its complexing temperature, single-crystal FePt NPs with controllable size and isotropic shape were obtained. The insight into the exploration of the specific roles of the reaction conditions and the formation mechanisms provided important information for controlling the morphology of the nanoparticles.
通过使用 Fe(CO)x-OAm（油胺，x < 5）作为 Fe 前体来减缓 FePt 纳米颗粒（NPs）的形成速率，通过透射电子显微镜（TEM）观察到 NPs 的成核和生长过程的时间依赖性。OAm 和 Fe(CO)5 的络合温度对 NPs 的成核速率和生长过程有很强的影响。TEM 分析表明，具有各向同性形状的 NPs 在整个合成过程中都是单晶的，并且通过扩散控制的奥斯特瓦尔德熟化（OR）生长机制形成。纳米棒颗粒首先通过任意取向的单晶的连接形成，然后两个晶体通过定向附着（OA）机制形成均匀的颗粒。在制备 Fe(CO)x-OAm 中使用的 OAm 与 Fe(CO)5 的比例对生长过程有显著影响，进而影响 FePt NPs 的形状、尺寸和尺寸分布。通过调整比例及其络合温度，可以获得具有可控尺寸和各向同性形状的单晶 FePt NPs。对反应条件和形成机制的具体作用的探索提供了重要信息，有助于控制纳米颗粒的形态。
