Fabrication of gold-silver bimetal nanoparticles/silicon nanoporous pillar array substrate and surface-enhanced Raman sc
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Fabrication of gold‑silver bimetal nanoparticles/silicon nanoporous pillar array substrate and surface‑enhanced Raman scattering detection Lingling Yan1 · Guoxiang Zhang1 · Hongxin Cai1 · Peng Yang1 · Liang Chen1 · Yongqiang Wang1 Received: 19 August 2020 / Accepted: 10 November 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract A novel gold-silver/silicon nanoporous pillar array substrate was prepared by a droplet-confined deposition technique and a replacement reaction method. Its surface-enhanced Raman scattering behaviors to R6G were studied. The substrate has not only high detection sensitivity, but also good signal uniformity and stability. The SERS detection limit is down to 1 0–13 M. The enhancement factor is 2.9 × 105 and the maximal relative standard deviation is only 9.2% at 10–7 M R6G. Moreover, it has a well stability with a slight drop in the spectrum intensity after placed for 35 days in air. This work suggested that the novel substrate has a potential application in environmental detection. Keywords SERS · Droplet-confined electroless deposition · Au–Ag · Silicon nanoporous pillar array
1 Introduction Surface-enhanced Raman scattering (SERS) has emerged as a rapid and powerful trace detection technology due to its ultrahigh sensitivity, non-contact and unique fingerprint identification [1–4]. The cleverly engineered substrates play an important role for SERS detection and various SERS materials have been attempted to boost the signal and decrease the detection limits [5–10]. In general, metal nanoparticles are considered to be powerful SERS substrates because hot spots formed by the metal nanoparticles intergap/nanotips can generate strong local electromagnetic fields [11–13]. Great efforts have been made for preparing efficient SERS substrate with abundant “hot spots” to enhance the local electromagnetic fields. Among these various SERS substrates, 3D porous structures embedded with noble metal nanoparticles have attracted more attention [14–17], such as porous silicon, porous polymers, and porous alumina membranes, owing to their larger specific surface area and 3D spatial structure which can fast adsorb more target molecules * Hongxin Cai [email protected] 1
School of Physics and Electronic Information Engineering, Henan Polytechnic University, Jiaozuo 454000, China
and then obtain better SERS performance. In particular, porous silicon materials are thought as a promising SERS substrate. Currently, various porous silicon structures including pyramidal Si [18–20] and Si nanopillar/nanowire arrays [21, 22] are used as the 3D substrate in most 3D Si-based SERS platforms. Multifarious methods including chemical vapor deposition, template method, metal-catalyzed electroless etching, and oxide-assisted growth have been carried out to fabricate 3D Si-based SERS platforms with high analytical performances. For example, Yan et al. successfully prepared a series of 3D Si-based SERS substrates based on silicon pyramid arrays (PSi) and Au–Ag nanoparti
