Key Laboratory of Materials Physics, Anhui Key Lab of Nanomaterials and Nanostructure, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China.
Analyst. 2013 Aug 21;138(16):4519-25. doi: 10.1039/c3an00750b. Epub 2013 Jun 18.
The production of SERS-active substrates which are uniform, sensitive, reproducibile and durable still remains an important issue. Here, we report a strategy for the fabrication of a large-area Ag-decorated TiO₂ nanograss SERS-active substrate by a simple solvothermal approach combined with Ag evaporation. The nanograss consists of dense rutile TiO₂ nanorods of about 5 nm in diameter and the decorated Ag nanoparticles are an average of 8 nm in diameter. The Ag protrusions and gaps between them contribute to three dimensional SERS "hot spots" which can be modulated by simply controlling the Ag evaporating parameters. The Ag-decorated TiO₂ substrate is highly efficient in detecting rhodamine 6G (R6G) and 4-aminothiophenol (4-ATP) molecules and has good homogeneity. An obvious red shift and even high enhancement of b₂ vibration mode were observed in detecting 4-ATP due to the effective charge transfer from the Ag atoms to sulfur atoms. The Ag-decorated TiO₂ substrate can be easily self-cleaned and reactivated by visible light irradiation without obvious degeneration of SERS signals. Our results demonstrate that the Ag-decorated TiO₂ substrate with high and homogeneous SERS activity has potential feasibility as a sensitive SERS probe.
制备具有均匀性、灵敏度、重现性和耐用性的 SERS 活性衬底仍然是一个重要问题。在这里，我们报告了一种通过简单的溶剂热方法结合 Ag 蒸发制备大面积 Ag 修饰 TiO₂纳米草 SERS 活性衬底的策略。纳米草由约 5nm 直径的密集锐钛矿 TiO₂纳米棒组成，修饰的 Ag 纳米颗粒平均直径为 8nm。Ag 突起和它们之间的间隙有助于形成三维 SERS“热点”，通过简单地控制 Ag 蒸发参数即可对其进行调制。Ag 修饰的 TiO₂衬底在检测罗丹明 6G（R6G）和 4-巯基苯胺（4-ATP）分子方面非常高效，并且具有良好的均一性。由于 Ag 原子向硫原子的有效电荷转移，在检测 4-ATP 时观察到明显的红移甚至 b₂振动模式的高增强。Ag 修饰的 TiO₂衬底可以通过可见光照射轻松自清洁和再激活，而 SERS 信号没有明显退化。我们的结果表明，具有高均匀 SERS 活性的 Ag 修饰 TiO₂衬底作为一种灵敏的 SERS 探针具有潜在的可行性。
