Thermally annealed Ag nanoparticles on anodized aluminium oxide for SERS sensing

Abstract

In this paper we report a study of novel thermally stable surface enhanced Raman scattering (SERS) substrates consisting of Ag nanoparticles immobilized on an anodized aluminum oxide (AAO) support.The morphological and chemical characteristics and the SERS activity of the Ag nanoparticles before and after the thermal treatment were evaluated using SEM, XPS, UV-vis and Raman spectroscopy. Our results show that the nanoporous surface of AAO significantly hinders the fusion of Ag nanoparticles to single large particles at up to 400 uC, preserving high SERS enhancement. XPS and SERS results indicate that exposure to high temperatures efficiently 'cleanses' the surface from citrate remnants, opening more binding sites for analytes on Ag nanoparticles. In addition, thermal decomposition of silver oxide occurs at 400 uC, ensuring a pure metallic surface and further enhancing SERS activity.

Ag Nanorods-Based Surface-Enhanced Raman Scattering: Synthesis, Quantitative Analysis Strategies, and Applications

“…As SERS performances of substrates are highly correlated with their shapes and sizes, it is vital to preserve their geometric shape during detection conditions especially for low melting temperature materials, such as silver. Studies demonstrated that dramatic morphologies changes and devastating sensitivity degradation were observed on Ag nanoparticle substrates under high temperature and enhanced thermal stability could be effectively obtained by integrating oxides into SERS substrates (Mai et al, 2012; Pinkhasova et al, 2013; Lou et al, 2014; Ma et al, 2015b). For example, Lou et al proved that capping TiO 2 layer on AgNRs via PVD effectively protected AgNRs morphology up to at least 100°C (Figure 5A) (Lou et al, 2014).…”

SERS substrates fabricated using ceramic filters for the detection of bacteria: Eliminating the citrate interference

“…Because of this benefit, several approaches for eliminating the citrate interference were examined. One method described by Pinkhasova et al [6] used thermal annealing after immobilizing Ag NPs prepared by the citrate reduction process on an anodized aluminum oxide surface. The SERS platforms then underwent heat treatment at 200, 300, 400, and 600 °C in a quartz tube furnace under ambient air.…”

Graphene: A Building Foundation for Efficient Plasmonic SERS Device

“…Single-layer graphene (SLG) coated with silver is used here to employ a simplified fabrication process for plasmonic application. The devices were thereafter annealed at sintering temperature (T s ) of 250°C, leads to an increase in average Ag nanoparticle size [27][28][29][30][31]. The morphology of as prepared (AsPrep) and annealed (As250) samples were analyzed by means of atomic force microscopy (AFM) technique.…”