Institute of Microengineering and Nanoelectronic (IMEN), Universiti Kebangsaan Malaysia, UKM Bangi 43600, Selangor, Malaysia.
Sensors (Basel). 2012;12(8):10309-25. doi: 10.3390/s120810309. Epub 2012 Jul 30.
The effect of morphology on the plasmonic sensing of the presence of formaldehyde in water by gold nanostructures has been investigated. The gold nanostructures with two different morphologies, namely spherical and rod, were prepared using a seed-mediated method. In typical results, it was found that the plasmonic properties of gold nanostructures were very sensitive to the presence of formaldehyde in their surrounding medium by showing the change in both the plasmonic peaks position and the intensity. Spherical nanoparticles (GNS), for example, indicated an increase in the sensitivity when the size was increased from 25 to 35 nm and dramatically decreased when the size was further increased. An m value, the ratio between plasmonic peak shift and refractive index change, as high as 36.5 nm/RIU (refractive index unit) was obtained so far. An expanded sensing mode to FD was obtained when gold nanostructures with nanorods morphology (GNR) were used because of the presence of two plasmonic modes for response probing. However, in the present study, effective plasmonic peak shift was not observed due to the intense plasmonic coupling of closely packed nanorod structures on the surface. Nevertheless, the present results at least provide a potential strategy for response enhancement via shape-effects. High performance plasmonic sensors could be obtained if controlled arrays of nanorods can be prepared on the surface.
金纳米结构的形态对水中甲醛存在的等离子体传感的影响进行了研究。使用种子介导法制备了具有两种不同形态的金纳米结构，即球形和棒形。在典型的结果中，发现金纳米结构的等离子体性质对其周围介质中甲醛的存在非常敏感，表现为等离子体峰位置和强度的变化。例如，球形纳米颗粒（GNS）的尺寸从 25nm 增加到 35nm 时，其灵敏度增加，而当尺寸进一步增加时，灵敏度则显著降低。迄今为止，已经获得了高达 36.5nm/RIU（折射率单位）的 m 值，即等离子体峰位移与折射率变化的比值。当使用具有纳米棒形态的金纳米结构（GNR）时，获得了扩展到 FD 的传感模式，因为存在两种用于响应探测的等离子体模式。然而，在本研究中，由于表面上紧密排列的纳米棒结构的强烈等离子体耦合，没有观察到有效的等离子体峰位移。然而，本研究结果至少提供了一种通过形状效应增强响应的潜在策略。如果可以在表面上制备出可控的纳米棒阵列，就可以获得高性能的等离子体传感器。
