Attomolar detection of 4-aminothiophenol by SERS using silver nanodendrites decorated with gold nanoparticles

Abstract

In the present work we report a simple, fast, reproducible and cheap methodology for SERS substrate fabrication of silver dendritic nanostructures (prepared by electrodeposition) decorated with gold nanospheres by electrophoretic deposition. This is the first report where a metal dendritic nanostructure has been decorated with another type of metal nanoparticles by this technique. The decorated nanostructures were used directly as SERS substrate using 4-aminothiophenol (4-ATP) as analyte. The objective of the decoration is to create more hot-spots in order to detect the analyte in a lower concentration. Decorated nanodendrites had a detection limit one million times lower than bare silver nanodendrites and all the substrates showed an increase in the Raman intensity at concentrations below 1 nM; because this concentration corresponds to the threshold for the formation of a monolayer resulting in a triple mechanism of intensity increase, namely electric field, chemical factor and hot-spots. 4-ATP was detected in attomolar concentration, which is below 1 ppq, corresponding to an analytical enhancement factor (AEF) in the order of 1015.

Wafer-scale silver nanodendrites with homogeneous distribution of gold nanoparticles for biomolecules detection

“…Recently, enormous efforts have been disseminated in formulating different architectures of silver-based NSs (e.g., AgNPs, Ag nanoflowers, core-shell NSs, dendrites, and other complex nanostructures) for the SERS activity because of its strong inter-particle near field coupling effects and strong surface plasmon resonances in the visible to the near-infrared spectral regime ( Ma et al., 2020 ; Li et al., 2012 ; Chaudhari et al., 2018 ; Wei et al., 2018 ; Tian et al., 2019 ; Jiang et al., 2017 ; Verma and Soni, 2021 ; Podagatlapalli et al., 2015 ; Ceballos et al., 2022 ). Among the existing AgNSs, silver nano-dendrites (AgNDs) have occupied a particular spot in SERS-based sensing applications spotted owing to their outstanding properties such as (a) ease of synthesis (b) adaptability (c) specific surface area (d) cost-effectiveness, (e) broadband hot electron generation, and so forth.…”

Using a mixture of vinasse-contaminant and H3PO4 as an efficient electrolyte for high performance flexible carbon nanotube-based supercapacitors

“…The CNT sheets acted as a nucleation substrate and facilitated the vertical growth of the nanostructures. Dendrites of this type have been used in applications of SERS for detection of rhodamine dye contaminants and as part of electrodes in SC [94,95]. Those dendrites are useful for the capacitive performance of the devices because they have more surface area than the conventional quasi-spherical particles of Ag/TiO 2 .…”