Surface-Enhanced Infrared Spectroscopy Using Nanometer-Sized Gaps
Surface-Enhanced Infrared Spectroscopy Using Nanometer-Sized Gaps
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DOI：
10.1021/nn500903v
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发表时间：
2014-05-01
期刊：
影响因子：
17.1
通讯作者：
Pucci, Annemarie
中科院分区：
文献类型：
--
作者：
Huck, Christian;Neubrech, Frank;Pucci, Annemarie
我们报道了单个金纳米天线以尖端到尖端二聚体结构排列的近场耦合，导致了红外中强烈的电磁场增强，这在表面增强红外光谱等传感应用中具有重要意义。我们定量地评价了厚度为5 nm的4，4‘-双(N-咔唑基)-1，1’-联苯测试层的振动激发强度随不同能隙大小的变化。具有最小间隙的二聚体(类似于3 nm)导致的信号增强比50 nm宽度的间隙高1个数量级以上。实验数据和有限差分时间域模拟的比较表明，尺寸小于10 nm的空位被不完美地填充，这意味着除了化学信息之外，还获得了纳米尺度上的形态信息。
We report on the near-field coupling of individual gold nanoantennas arranged in tip-to-tip dimer configuration, leading to strong electromagnetic field enhancements in the infrared, which is of great interest for sensing applications such as surface-enhanced infrared spectroscopy. We quantitatively evaluated the enhancement of vibrational excitations of a 5 nm thick test layer of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl as a function of different gap sizes. The dimers with the smallest gaps under investigation (similar to 3 nm) lead to more than 1 order of magnitude higher signal enhancement with respect to gaps of 50 nm width. The comparison of experimental data and finite-difference time-domain simulations reveals a nonperfect filling of the gaps with sizes below 10 nm, which means that morphological information on the nanoscale is obtained additionally to chemical information.