銀奈米線之合成

Abstract

在此研究中，我們展示一系列利用 (Me3Si)4Si 將AgCl與AgNO3還原成銀金屬的反應，並且討論可能的反應機制。(Me3Si)4Si 與AgCl反應的主產物為具有直徑數十微米的銀金屬粉末。將AgCl包覆PDMS後與 (Me3Si)4Si反應，其產物粉末的直徑急劇地縮減到僅有數百奈米，比起沒有加入PDMS包覆的粉末小很多。在此反應中，PDMS與反應溫度扮演著重要的腳色。在高溫時奈米銀粉末與奈米銀棒的尺寸分布較低溫時不均勻。在低溫時主產物為直徑約100奈米均勻大小的奈米銀粉，且包覆在PDMS內部的AgCl不能完全被還原成銀金屬。在AgNO3 與 (Me3Si)4Si的反應中，我們發現一個非凡高產率的奈米銀線合成法，此方法只需要一個步驟而且不需要溶劑。原生(in situ)的非結晶相氧化矽殼層式是簡化反應的重要因素。氣固相反應成長(VSRG, Vapor-Solid Reaction Growth)模型可以應用在此研究中。

In this work, we demonstrate a serious reactions of (Me3Si)4Si that are able to reduce AgCl and AgNO3 into metallic Ag, and propose a possible reaction mechanism. The major product from AgCl and (Me3Si)4Si is Ag particles with tens micrometer in diameter. In the reaction of (Me3Si)4Si and AgCl encapsulated in PDMS, the particle sizes are dramatically reduced to hundreds nanometer in diameter that are much smaller than without adding PDMS. In the reaction, PDMS and reaction temperature are important roles. At high temperature, the size distribution of silver nanoparitcles and nanorods is larger than at low temperature. In contrast, at low temperature the nanopartices have uniform sizes about 100 nm in diameter, and internal AgCl encapsulated in PDMS cannot be totally reduced. In the reaction of AgNO3 and (Me3Si)4Si, we discover a remarkably simple one-step solvent-free method to synthesize Ag nanowires in high yield. One of the key factors to the simplicity is the in situ generation of the amorphous silica shell layer. The vapor-solid reaction growth (VSRG) model can use as the reaction mechanism in this work.