Nanoparticle Cluster Arrays for High-Performance SERS through Directed Self-Assembly on Flat Substrates and on Optical Fibers
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- 作者：Fung Ling Yap ; Praveen Thoniyot ; Sathiyamoorthy Krishnan ; Sivashankar Krishnamoorthy
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：March 27, 2012
- 年：2012
- 卷：6
- 期：3
- 页码：2056-2070
- 全文大小：1019K
- 年卷期：v.6,no.3(March 27, 2012)
- ISSN：1936-086X
文摘
We demonstrate template-guided self-assembly of gold nanoparticles into ordered arrays of uniform clusters suitable for high-performance SERS on both flat (silicon or glass) chips and an optical fiber faucet. Cluster formation is driven by electrostatic self-assembly of anionic citrate-stabilized gold nanoparticles (11.6 nm diameter) onto two-dimensionally ordered polyelectrolyte templates realized by self-assembly of polystyrene-block-poly(2-vinylpyridine). A systematic variation is demonstrated for the number of particles (N 鈮?5, 8, 13, or 18) per cluster as well as intercluster separations (Sc 鈮?37鈥?0 nm). Minimum interparticle separations of <5 nm, intercluster separations of 10 nm, and nanoparticle densities on surfaces as high as 7 脳 1011/in.2 are demonstrated. Geometric modeling is used to support experimental data toward estimation of interparticle and intercluster separations in cluster arrays. Optical modeling and simulations using the finite difference time domain method are used to establish the influence of cluster size, shape, and intercluster separations on the optical properties of the cluster arrays in relation to their SERS performance. Excellent SERS performance, as evidenced by a high enhancement factor, >108 on flat chips and >107 for remote sensing, using SERS-enabled optical fibers is demonstrated. The best performing cluster arrays in both cases are achievable without the use of any expensive equipment or clean room processing. The demonstrated approach paves the way to significantly low-cost and high-throughput production of sensor chips or 3D-configured surfaces for remote sensing applications.