新穎無模板中空Au,Ag,Cu及其合金奈米粒子---合成、塊式高分子自組裝及可調控光學特性之研究

Abstract

中空(hollow)奈米粒子由於具有高表面積、低材料用量、多樣化之外觀形貌、以及特殊之物理化 學性質，使其成為未來極具發展潛力之重要奈米結構。舉例而言，藉由調控中空Au 粒子殼層(shell) 之厚度，可以使其表面電漿共振(SPR)波長紅位移數百奈米，大幅提昇其在感測器上之應用[1,2]。另外 一個有趣的例子是中空Pd 奈米粒子能夠承受之觸媒反應(Suzuki Coupling 反應)次數，遠遠高於實心 Pd 奈米粒子[3,4]。然而，由於中空製程參數掌握不易，加上中空結構大幅增加分析上之複雜度，使得 中空奈米粒子之研究至今仍相當缺乏。因此，關於中空奈米粒子之結構設計、製備、乃至於特性分析 之研究，均充滿了學術、技術、與應用之挑戰與重要性。 本研究計畫擬利用「伽凡尼取代反應(Galvanic Replacement Reaction)」來製備形貌特殊之新穎中 空Au，Ag，Cu 及其合金(Au-Ag，Au-Cu)奈米粒子。並藉由Block copolymer (PS-P2VP)之自組裝特性， 在玻璃基板上製備二維或三維中空/實心奈米粒子週期性陣列結構。在中空粒子結構之解新方面，利用 非臨場(ex-situ)分析，例如X 光繞射分析(XRD)、高解析電子顯微鏡(HREM)、X 光光電子能譜(XPS) 之外，加上臨場之溫度控制UV-vis 吸收光譜特性分析，可以了解中空奈米粒子之形貌、結構、合金成 分、氧化狀態、以及自組裝週期性陣列結構等因子對表面電漿共振(SPR)之影響。

Hollow metallic nanoparticles have become the most potential nanostructures recently due to their high specific surface area, use less material, multiplex morphologies, as well as unique physical and chemical properties relative to their sold nanoparticles. For instance, with a slight change of the shell thickness of Au hollow nanoparticles, the surface plasmon resonance (SPR) peaks greatly shift for several hundred nanometers [1,2]. In another example, hollow Pd nanoparticles remain highly active for many reaction cycles (Suzuki coupling reactions) comparing with only one cycle of solid Pd nanoparticles [3,4]. However, till now research data of hollow nanoparticles are still lacking because of difficulties on structural controls and characterizations. Therefore, studies on structural design, synthesis, as well as property analysis of hollow nanoparticles are of importance not only for the scientific interests but also for the application needed in the future. In the research plane, hollow Au, Ag, Cu and their alloyed (Au-Ag and Au-Cu) nanoparticles with specific morphologies will be synthesized by galvanic replacement reactions. The hollow/solid metallic nanoparticles prepared will then be deposited with various 2D or 3D periodic patterns onto glass substrates using self-assembly of poly(styrene-b-2-vinylpyridine) (PS-P2VP) block copolymer. X-ray diffractometer (XRD), high-resolution electron microscope (HREM), and x-ray photoelectron spectroscopy (XPS) will be mainly used for the ex-situ identification of the morphologies, structures, compositions and the oxidation conditions of the generated hollow nanoparticles. The temperature-controlled UV-vis spectroscopy will be built for in-situ observations of surface plasmon resonance (SPR) peak shift during the galvanic replacement reactions. Effects of the structural parameters as well as the self-assembly patterns on the surface plasmon resonance (SPR) will be discussed.