原位水热法合成石墨烯基纳米银及在导电胶中的应用

In situ hydrothermal synthesis of nanosilver grafted on graphene and application for electrically conductive adhesive

以环氧树脂为基体树脂添加导电材料组成的导电胶具有加工温度低、线分辨率小、对环境污染小等特点,是新型理想的电子封装互连材料,将具有较高导电性的石墨烯基纳米银掺杂在基体树脂中具有增加导电通路的作用。本研究在不添加表面活性剂等其他辅助试剂的反应环境中,用原位还原银氨溶液和氧化石墨烯获得石墨烯基纳米银复合材料,采用扫描电子显微镜、透射电子显微镜、Χ射线衍射仪和拉曼光谱仪对石墨烯基纳米银复合材料进行了形貌及结构表征,并将复合材料与银粉、环氧树脂基体掺杂制备导电胶,在150℃下固化2 h后,用四探针电阻率仪测试导电胶的电学性能。测试结果表明:平均直径为80 nm的纳米银粒子均匀的分散在石墨烯表面;当在基体树脂和银粉中添加0.2份复合材料后,制备的导电胶的电阻率降至1.4×10^(-4)Ω·cm,与未掺杂石墨烯基纳米银导电胶的电阻率2.2×10^(-4)Ω·cm相比,其电学性能明显提高。

Electrically conductive adhesive based on epoxy and conductive materials have been considered as the new promising material for electronic packaging because of the advantages of low processing temperature,fine pitch interconnect and environmental friendly.However,the key question is how to improve the electrical properties of electrically conductive adhesive.The nanosilver based on graphene have been used in the electrically conductive adhesive as a result of the excellent electrical.The number of effective conductive paths were improved after doping nanosilver based on graphene into epoxy.So nanosilver based on graphene was in situ prepared via silver-ammonia solution and graphene oxide as initial solution without other supported reagents.Scanning Electron Microscopy,Transmission Electron Microscopy,X-ray diffraction and Raman spectroscopy were applied to analyze the morphologies and structures of nanosilver based on graphene.Then electrically conductive adhesive was prepared by mixing nanosilver based on graphene,silver flakes and epoxy together.The electrical properties of electrically conductive adhesive were tested by four-point probe method after cured at 150 ℃ for 2 h.The result shows that nanosilver particles are dispersed on the surface of graphene layers uniformly and the average diameter of nanosilver particles is 80 nm.The electrical properties of electrically conductive adhesive was improved when the nanosilver based on graphene reached 0.2portion.