Evaluation of an Electrodeposited Bimetallic Cu/Ag Nanostructured Screen Printed Electrode for Electrochemical Surface-Enhanced Raman Spectroscopy (EC-SERS) Investigations

Abstract

The field of plasmonics has experienced rapid growth over the past decade with a host of emerging applications including single molecule sensing and plasmon-assisted catalysis. The vast majority of these applications use either silver or gold as the plasmonic metal, which are both high cost and face earth-abundance limitations in the next 100 years. Recent efforts have focused on taking advantage of the plasmonic properties of copper, a more abundant and low cost coinage metal as a sustainable route for plasmonic applications. In particular, there has been great interest in developing copper substrates capable of reliable and efficient enhancement of Raman signals for use in surface-enhanced Raman spectroscopy (SERS) sensing. Herein we describe a sequential electrodeposition technique whereby highly functional and robust Cu/Ag bimetallic SERS-active screen printed electrodes can be produced rapidly and at low cost, which display excellent plasmonic performance and are capable of supporting surface-plasmon assisted catalysis (SPAC). This modified screen printed electrode allows for the in situ spectroelectrochemical investigation of surface redox processes using a sustainable alternative to traditional monometallic electrodes. Over the past several decades there has been growing interest in the field of plasmonics, in particular due to the many applications which are possible now, and may be possible in the future with such a technology. In particular, SERS-based sensing, which relies heavily on the localized surface plasmon resonance (LSPR) to contribute to the large enhancement in signal, has shown promise for a multitude of applications ranging from medical diagnostics to art conservation to environmental monitoring.1-5 While Ag and Au form the bulk of metals used for SERS-based sensing, there is growing interest in the use of Cu as a plasmonic substrate due to its relatively low cost and high earth abundance. [6][7][8] In particular, large scale applications of plasmonics such as in plasmon-enhanced photovoltaics are going to require exploration of more readily scalable metals such as Cu. Cu-based SERS substrates were first explored in the early 1980's, but recent progress in this area has been slow. Limitations with the use of Cu for SERS-based sensing extend from two main issues -the ease of oxidation of Cu, which leads to a dampening of the plasmon resonance, as well as a lack of reported stable nanostructures.10 In addition, as with Au, Cu cannot be used for plasmonic applications below ∼600 nm due to interfering interband transitions.10 That being said, in recent years several groups have been working to realize the possibility of Cu-based SERS. For example, Chen et al. reported a highly efficient nanoporous Cu SERS substrate produced by dealloying of a Cu 30 Mn 70 alloy.11 In this case, selective etching of the Mn resulted in Cu nanopores with tunable sizes. In 2014, Bassetto et al. evaluated a copper-based sphere segment void (SSV) SERS structure produced using a combination of nanosphere lithography a...

Electrodeposition of Cu-Ag Alloy Films at n-Si(001) and Polycrystalline Ru Substrates

“…Characterized by its complete immiscibility at room temperature [1], the Ag-Cu alloys have been used in fields such as bactericides [2], decorative artifacts (depletion gilding) [3,4], electrocatalysis (H 2 O 2 reduction [5], ammonia oxidation [6], and CO as well CO 2 reduction [7][8][9][10]), electrical contacts (interconnects [11], flexible electronics [12] and conductive inks [13]), sensors (electrochemical [14,15] or based on localized surface plasmon resonance [16][17][18][19]), usually in the form of nano-particles or core-shell nanowires. To the best of our knowledge, the Cu-Ag alloys have been synthesized using electron beam co-evaporation [1,20], magnetron sputtering [21], co-incipient wetness and coimpregnation [6,14], direct mixing of nanoparticles, mechanical alloying [22,23], laser ablation and irradiation [16,17], Cu electrodeposition followed by galvanic replacement with Ag [5,7,12], and electroless deposition [2,13,15,24].…”

Surface‐enhanced Raman spectroscopy for successful probing of itraconazole within poly(lactic‐co‐glycolic acid) nanoparticles

“…A direct current of 1.0 mA was applied to the plates during 60 min, producing nanostructured silver substrates (see Figures S1 and S2). Next, the plates were removed out from the chamber and dried with nitrogen flow. All SER spectra were recorded after diluting the samples with distilled water (20 μl), dropping the suspension onto the nanostructure silver substrate and drying the wet substrate with nitrogen flux.…”

Spectroelectrochemistry, the future of visualizing electrode processes by hyphenating electrochemistry with spectroscopic techniques

“…There is a large variety of different materials for Raman electrodes. Reports range from standard metallic electrodes such as Au electrodes, to cells made by 3D printing, 130 screen-printed electrodes [131][132][133][134][135][136][137][138] and even electrodes on fabric. 139 In the literature, several different cell configurations are described.…”