Holst Centre/IMEC, High Tech Campus 31, 5656 AE Eindhoven, The Netherlands.
Nanotechnology. 2011 Jul 22;22(29):295303. doi: 10.1088/0957-4484/22/29/295303. Epub 2011 Jun 17.
The refractive index sensitivity of localized surface plasmon resonance sensors can be improved by placing the plasmonic metal particles on pillars instead of on a planar substrate. In this paper, a simple and versatile colloidal lithography method for the fabrication of plasmonic Au islands on top of polymer nanopillars is described. The pillar height is controlled by varying the thickness of the initial polymer film. An increased pillar height results in a blue shift of the absorption spectrum of the Au islands. This is explained by a decreased effective refractive index around the islands. For pillars higher than approximately 40 nm no further blue shift is observed, in agreement with the decay length of the electromagnetic field around the islands. Pillar-supported Au islands were also fabricated on a flexible foil, demonstrating the potential of the method described here for the fabrication of flexible plasmonic substrates. Benefits and limitations of the method and of using polymers as the pillar material are discussed.
将等离子体金属颗粒置于立柱上而不是置于平面衬底上，可以提高局域表面等离子体共振传感器的折射率灵敏度。本文描述了一种简单而通用的胶体光刻法，用于在聚合物纳米立柱顶部制备等离子体金岛。通过改变初始聚合物膜的厚度来控制立柱的高度。立柱高度的增加导致金岛的吸收光谱发生蓝移。这可以通过岛周围有效折射率的降低来解释。对于高于约 40nm 的立柱，没有观察到进一步的蓝移，这与岛周围电磁场的衰减长度一致。还在柔性箔上制备了立柱支撑的 Au 岛，展示了这里描述的方法在制备柔性等离子体衬底方面的潜力。讨论了该方法和使用聚合物作为立柱材料的优缺点。
