Silver nanodendrites for ultralow detection of thiram based on surface-enhanced Raman spectroscopy

Abstract

Metal nanostructures with highly branched morphologies are attractive due to their fascinating plasmonic properties which are related to their unique morphological features. In this work a simple fabrication methodology is used for fabrication of surface-enhanced Raman spectroscopy (SERS) substrates composed of branched silver nanostructures with dendritic morphology. The high Raman intensity enhancement factor of the order ∼10 10 was achieved which allows the detection of ∼zeptomole thiram molecules by SERS substrates. The appearance of new bands at 344 cm −1 and 1521 cm −1 provides an evidence of contribution of chemical enhancement in SERS. The observed spectral changes in SERS spectrum originate from the adsorption of the analyte on the metal surface and provide an insight into molecule-metal interaction in SERS. The extreme sensitivity of SERS substrates is discussed in terms of the distinction between electromagnetic and chemical enhancement mechanisms. Moreover, the highly sensitive SERS substrates were used for simultaneous detection of Rhodamine B and thiram molecules from their mixture with different individual concentrations demonstrating detection capabilities for the identification of pesticides with dye molecules.

Ultrasensitive surface‐enhanced Raman spectroscopy detection of explosive molecules with multibranched silver nanostructures

“…The 3D multibranched AgNSts were prepared by the chemical reduction method with the optimum concentrations and the molar ratio of the reagents. [22,23] The welldefined 3D multispiked AgSs were prepared under the optimized reaction parameters AgNO 3 :L-AA (R 1 ) and AgNO 3 :PVP (R 2 ) with values of 0.05 and 2.5, respectively (Figure 1a). The 3D multibranched AgSs with an average size of 2.61 μm exhibit sharp branches with an average arm length of approximately 810 nm and an average tip diameter of 90 nm, as shown in Figure 1c.…”

“…The dendritic AgNSts were prepared using a facile single‐step chemical synthesis procedure with different reaction parameters. [ 22 ] The chemical reduction of AgNO 3 was carried out at room temperature, employing l ‐AA in the presence of PVP under the optimized reaction parameters. For the fabrication of the dendritic AgNSts, 0.25‐ml l ‐AA (500 mM) aqueous solution was dropped to 5‐ml AgNO 3 (1 mM) aqueous solution, and 0.2‐ml PVP (10 mM) aqueous solution was added in a dropwise manner to the “nanoparticles” solution.…”

“…Several synthesis routes have been adopted for the fabrication of dendritic AgNSts using via templating, [16] replacement reaction, [17] electrochemical deposition, [18,19] and chemical reduction. [20][21][22] In the replacement reaction, the formation of the Ag nanodendrites is governed by the oriented attachment and diffusion of metal nanocrystals precursors. Highly sensitive fern-like silver dendrites have been reported as active SERS platforms for the nitenpyram molecule detection with $picomolar detectability.…”

“…The effect of shape-directing or capping agents on the morphological evolution of nanodendrites was studied to prepare the hierarchical dendritic structures. [21,22] The single-step chemical reduction method was employed for the multibranched silver stars (AgSs) fabrication and utilized for the SERS detection of multiple analytes in the individual as well as multiplexed form. [23] In this work, the chemically synthesized 3D multibranched AgNSts (silver nanodendrites [AgNDs] and silver stars [AgSs]) are investigated for the ultrasensitive and multiplexed detection of the different analyte molecules; organic dye, pesticide, and explosive molecules by SERS.…”

SERS chemical enhancement by copper ‐ nanostructures: Theoretical study of Thiram pesticide adsorbed on Cu20 cluster

“…These phenomena were also confirmed by Verma et al using silver nanodendrites. [9] The prediction of Raman and SERS spectra has commonly been investigated using density functional theory (DFT). Metallic cluster models are often used to reproduce nanoparticle surface.…”