Lee Youngil, Choi Jun-Rak, Lee Kwi Jong, Stott Nathan E, Kim Donghoon
Samsung Electro-Mechanics, Central R&D Institute, Electro-Materials and Devices (eMD) Center, Functional Materials Technology Group, Nanomaterials Team, 314 Maetan-3-Dong Yeongtong-Gu, Suwon, Gyeonggi-Do 443-743, Korea.
Nanotechnology. 2008 Oct 15;19(41):415604. doi: 10.1088/0957-4484/19/41/415604. Epub 2008 Sep 4.
Copper nanoparticles are being given considerable attention as of late due to their interesting properties and potential applications in many areas of industry. One such exploitable use is as the major constituent of conductive inks and pastes used for printing various electronic components. In this study, copper nanoparticles were synthesized through a relatively large-scale (5 l), high-throughput (0.2 M) process. This facile method occurs through the chemical reduction of copper sulfate with sodium hypophosphite in ethylene glycol within the presence of a polymer surfactant (PVP), which was included to prevent aggregation and give dispersion stability to the resulting colloidal nanoparticles. Reaction yields were determined to be quantitative while particle dispersion yields were between 68 and 73%. The size of the copper nanoparticles could be controlled between 30 and 65 nm by varying the reaction time, reaction temperature, and relative ratio of copper sulfate to the surfactant. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images of the particles revealed a spherical shape within the reported size regime, and x-ray analysis confirmed the formation of face-centered cubic (FCC) metallic copper. Furthermore, inkjet printing nanocopper inks prepared from the polymer-stabilized copper nanoparticles onto polyimide substrates resulted in metallic copper traces with low electrical resistivities (≥3.6 µΩ cm, or ≥2.2 times the resistivity of bulk copper) after a relatively low-temperature sintering process (200 °C for up to 60 min).
近年来，由于铜纳米颗粒具有有趣的特性以及在许多工业领域的潜在应用，它们受到了相当多的关注。一种可利用的用途是作为用于印刷各种电子元件的导电油墨和浆料的主要成分。在本研究中，通过相对大规模（5升）、高通量（0.2摩尔）的工艺合成了铜纳米颗粒。这种简便的方法是在聚合物表面活性剂（PVP）存在的情况下，通过在乙二醇中用次磷酸钠化学还原硫酸铜来实现的，加入PVP是为了防止聚集并使所得胶体纳米颗粒具有分散稳定性。反应产率被确定为定量的，而颗粒分散产率在68%至73%之间。通过改变反应时间、反应温度以及硫酸铜与表面活性剂的相对比例，可以将铜纳米颗粒的尺寸控制在30至65纳米之间。颗粒的场发射扫描电子显微镜（FE-SEM）和透射电子显微镜（TEM）图像显示在所报道的尺寸范围内呈球形，X射线分析证实形成了面心立方（FCC）金属铜。此外，将由聚合物稳定的铜纳米颗粒制备的喷墨印刷纳米铜油墨印刷到聚酰亚胺基板上，经过相对低温的烧结过程（200℃，最长60分钟）后，得到了具有低电阻率（≥3.6µΩ·cm，或≥块状铜电阻率的2.2倍）的金属铜迹线。
