中文摘要 金屬奈米粒子的大小對可見光的吸收位置有密切的關係。本論文主要為有機單層包覆的奈米金球對離子的光譜感應行為之研究。我們以相轉移合成法製備表面覆有單層化合物A之奈米金球(3.35 nm)。在陰離子H2PO4-的存在下，此奈米金球的吸收峰強度呈現下降情形。此外，我們亦利用352.0 nm紫外光來異構化化合物A中的二苯乙烯雙鍵，使之成為順式構形，此時其對於陰離子H2PO4-之感應變得更加顯著，且溶液顏色由原先的淡紅色變為透明無色；對於陽離子的感應，異構化前化均不明顯。針對此現象，我們於是深入探討光學異構化反應時間的長短與金球對陰離子H2PO4-感應之靈敏度間的關係，結果顯示光學異構化可能導致化合物A脫離金球表面。 Abstract The electronic absorption properties of metal nanoparticles strongly depend on their sizes. This thesis reports the ion sensing behavior of gold nanoparticles that are capped with a monolayer of organic species, namely, compound A. These nanoparticles are prepared by a phase transfer technique and 3.35 nm in diameter. In the presence of anion H2PO4-, the intensity of the characteristic absorption peak of gold nanoparticles decreases. When the gold nanoparticles were irradiated with 352 nm light, which could in principle isomerizes the trans-stilbene group to the cis form, the spectral response to H2PO4- becomes more significant, and the pink color solution turns to colorless. In contrast, the nanoparticles show no spectral response to metal ions either before or after irradiation. We have also investigated the relationship between the irradiation time and the extent of spectral response for the nanoparticles to H2PO4-. The results indicate that photoisomerization of the compound A on the nanoparticles might cause a desorption of A from the gold surface.
