Obviously Angular, Cuboid-Shaped TiO2 Nanowire Arrays Decorated with Ag Nanoparticle as Ultrasensitive 3D Surface-Enhanced Raman Scattering Substrates

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• 作者：Zhigao Dai ; Gongming Wang ; Xiangheng Xiao ; Wei Wu ; Wenqing Li ; Jianjian Ying ; Junfeng Zheng ; Fei Mei ; Lei Fu ; Jiao Wang ; Changzhong Jiang
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：October 2, 2014
• 年：2014
• 卷：118
• 期：39
• 页码：22711-22718
• 全文大小：495K
• ISSN：1932-7455

文摘

In recent years, surface-enhanced Raman scattering (SERS) has received renewed attention, because of its nondestructive, ultrasensitive, and rapid analysis, detection, and imaging. Development of SERS substrates with high sensitivity and excellent stability is of great importance to realize its practical applications in trace analysis, bio diagnosis, and in vivo studies. In this work, we demonstrate wafer-scale Ag-nanoparticle-decorated, obviously angular, quasi-vertically aligned cuboid-shaped TiO₂ nanowire arrays (TiO₂-NWs), as ultrasensitive and uniform 3D SERS substrates. A detection limit of 10^鈥?5 M rhodamine 6G molecules and an analytical enhancement factor of 10¹² were achieved on the cuboid-shaped TiO₂-NWs arrays with 9 min Ag-sputtering. This is the best result obtained among the literature values on Ag-modified semiconductor SERS substrates. More importantly, the optimized TiO₂-Ag also exhibits excellent stability and uniformity. The excellent SERS performance is attributed to the 鈥渃usp鈥?and 鈥済aps鈥?formed on the Ag-NPs coated TiO₂ nanowire arrays, which create a huge number of SERS 鈥渉ot spots鈥? The experimental results were further confirmed by theoretical calculations of the spatial distributions of electromagnetic field intensity. The prepared TiO₂-Ag SERS substrates with such low detection limit and high sensitivity will provide a promising candidate for practical chemical and biological detection.