光谱学研究银纳米颗粒在玻璃中的生成规律

Forming mechanism of Ag nanoparticles in silicate glasses by optical spectroscopy

通过离子交换法将银离子引入白硅酸盐玻璃和绿硅酸盐玻璃,利用光致发光(photolum ines-cence-PL)和光吸收(optical absorption-OA)谱研究银离子的团簇化、成核和生长。由于白硅酸盐玻璃不含二价铁离子,因此,银纳米颗粒形成困难,颗粒体积分数非常低,以致样品中银纳米颗粒的共振吸收峰不明显。在这种条件下,样品中存在大量银离子和银的小原子团簇。在绿玻璃中,氧化铁含量较高,引入到玻璃中的银离子大部分被二价铁离子还原成中性银原子,通过热处理,银离子在玻璃中成核和生长。在相近的热处理条件下,绿玻璃有利于银纳米颗粒的生成。银纳米颗粒在形成过程中,消耗大量银离子,造成样品的发光强度逐渐降低。

Ag ions were introduced into white silicate and green silicate glasses by ion - exchanged methglass, and the surface plasma resonance absorption can not be observed obviously. In these exists amounts of Ag ^＋ ions and small Ag clusters. When Ag ^＋ ions are introduced into green glasses there glasses, Ag ^＋ ions are reduced into neutral Ag atoms by Fe^2＋ ions, and Ag particles nucleate and grow in a suitable condition of thermal treatment. Thus it is much easier to form Ag nanoparticles in green glass than in white glass at nearly the same processes. The PL intensity decreases gradually with the transformation of Ag ions to Ag nanoparticles.