Technology Development Division, Korea Advanced Nanofab Center (KANC), Suwon 443270, Korea.
Nanoscale. 2015 Dec 28;7(48):20717-24. doi: 10.1039/c5nr05877e. Epub 2015 Nov 25.
A novel technique for the selective photochemical synthesis of silver (Ag) nanoparticles (NPs) on ZnO nanorod arrays is established by combining ultraviolet-assisted nanoimprint lithography (UV-NIL) for the definition of growth sites, hydrothermal reaction for the position-controlled growth of ZnO nanorods, and photochemical reduction for the decoration of Ag NPs on the ZnO nanorods. During photochemical reduction, the size distribution and loading of Ag NPs on ZnO nanorods can be tuned by varying the UV-irradiation time. The photochemical reduction is hypothesized to facilitate the adsorbed citrate ions on the surface of ZnO, allowing Ag ions to preferentially form Ag NPs on ZnO nanorods. The ratio of visible emission to ultraviolet (UV) emission for the Ag NP-decorated ZnO nanorod arrays, synthesized for 30 min, is 20.5 times that for the ZnO nanorod arrays without Ag NPs. The enhancement of the visible emission is believed to associate with the surface plasmon (SP) effect of Ag NPs. The Ag NP-decorated ZnO nanorod arrays show significant SP-induced enhancement of yellow-green light emission, which could be useful in optoelectronic applications. The technique developed here requires low processing temperatures (120 °C and lower) and no high-vacuum deposition tools, suitable for applications such as flexible electronics.
建立了一种在 ZnO 纳米棒阵列上选择性光化学合成银（Ag）纳米粒子（NPs）的新方法，该方法结合了紫外辅助纳米压印光刻（UV-NIL）用于定义生长点、水热反应用于 ZnO 纳米棒的位置控制生长以及光化学还原用于在 ZnO 纳米棒上装饰 Ag NPs。在光化学还原过程中，通过改变 UV 照射时间可以调节 ZnO 纳米棒上 Ag NPs 的尺寸分布和负载量。假设光化学还原促进了表面吸附的柠檬酸根离子，使 Ag 离子优先在 ZnO 纳米棒上形成 Ag NPs。对于光化学还原 30 分钟合成的 Ag NP 修饰 ZnO 纳米棒阵列，可见光发射与紫外（UV）发射的比值是没有 Ag NPs 的 ZnO 纳米棒阵列的 20.5 倍。可见光发射的增强与 Ag NPs 的表面等离子体（SP）效应有关。Ag NP 修饰的 ZnO 纳米棒阵列显示出明显的 SP 诱导的黄绿光发射增强，这在光电应用中可能很有用。这里开发的技术需要低温处理（120°C 及以下）和无需高真空沉积工具，适用于柔性电子等应用。
