Facile Nanostructured Substrate Preparation Using Gold Nanocuboids for SERS

Pablo Genaro Martínez-Torres,Juan Luis Pichardo-Molina,Pablo Eduado Cardoso-Ávila,Monica Monserrat Martínez-García

doi:10.5772/60500

Abstract

In the present work, we report a practical fabrication method of gold-aluminium substrates for surface enhanced Raman spectroscopy. A commercial aluminium-foil was used to fabricate SERS substrates by depositing gold nanocuboids and faceted particles onto their surfaces using the drop-drying method. The gold nanoparticles were characterized by ultraviolet-visible spectroscopy, while the size and morphology were determined by field emission scanning electron microscopy. The performance of the substrates was investigated using Rhodamine 6G in a water solution where a volume of 3 μl was placed on the surfaces of the SERS substrates, and the Raman spectra were immediately acquired using diode laser excitation at 785 nm. The estimated analytical enhancement factor of the gold-aluminium substrates was 1.8 × 106, using a solution of Rhodamine 6G with a concentration of 1 × 109 (0.4796 ppb). We show that our SERS substrates can be easily fabricated, and that they are reproducible and have suitable surface uniformity, thus allowing one to analyse Rhodamine 6G not only as a dry sample, but also in a solution.

Highlights

The development of active substrates using noble metal nanoparticles (NPs) for surface-enhanced Raman spectro‐ scopy (SERS) is an important topic in the detection and characterization of chemical species at the single-molecule level of detection
Substrates with a high enhancement factors (EF) open the possibility of carrying out applications at the single-molecule level of detection [7, 8], which is possible through the formation of hot spots; the so-called hot spots are formed at interparticle gaps of ≤ 10nm
The use of colloids which are deposited on prepared solid surfaces by means of dropcasting, immersion, self-assembly, aggregation, dimmers or core satellite formation offers better enhancement factors; different reports have shown that these methods have good efficiency in the formation of hot spots [10], but it is well known that the use of colloidal NPs for the fabrication of reproducible SERS substrates with large uniform hot spot areas remains a big challenge

Summary

Introduction

The development of active substrates using noble metal nanoparticles (NPs) for surface-enhanced Raman spectro‐ scopy (SERS) is an important topic in the detection and characterization of chemical species at the single-molecule level of detection. The use of colloids which are deposited on prepared solid surfaces by means of dropcasting, immersion, self-assembly, aggregation, dimmers or core satellite formation offers better enhancement factors; different reports have shown that these methods have good efficiency in the formation of hot spots [10], but it is well known that the use of colloidal NPs for the fabrication of reproducible SERS substrates with large uniform hot spot areas remains a big challenge. For all these reasons, the design and fabrication of solid SERS substrates is still a hot area of research. We report a facile fabrication of SERS sub‐ strates using a simple drop-drying method: one drop of

Chemical materials

Gold nanostructure synthesis

SERS Substrate and sample preparation

Characterization

Results and discussion

Conclusions