Single-step fabrication of electrodes with controlled nanostructured surface roughness using optically-induced electrodeposition

Abstract

The customized fabrication of microelectrodes from gold nanoparticles (AuNPs) has attracted much attention due to their numerous applications in chemistry and biomedical engineering, such as for surface-enhanced Raman spectroscopy (SERS) and as catalyst sites for electrochemistry. Herein, we present a novel optically-induced electrodeposition (OED) method for rapidly fabricating gold electrodes which are also surface-modified with nanoparticles in one single step. The electrodeposition mechanism, with respect to the applied AC voltage signal and the elapsed deposition time, on the resulting morphology and particle sizes was investigated. The results from SEM and AFM analysis demonstrated that 80-200 nm gold particles can be formed on the surface of the gold electrodes. Simultaneously, both the size of the nanoparticles and the roughness of the fabricated electrodes can be regulated by the deposition time. Compared to state-of-the-art methods for fabricating microelectrodes with AuNPs, such as nano-seed-mediated growth and conventional electrodeposition, this OED technique has several advantages including: (1) electrode fabrication and surface modification using nanoparticles are completed in a single step, eliminating the need for prefabricating micro electrodes; (2) the patterning of electrodes is defined using a digitally-customized, projected optical image rather than using fixed physical masks; and (3) both the fabrication and surface modification processes are rapid, and the entire fabrication process only requires less than 6 s.

Light-addressable electrochemistry at semiconductor electrodes: redox imaging, mask-free lithography and spatially resolved chemical and biological sensing

“…We used the projector and adjustments of these three variable 44,45 and Au nanoparticles, 46 and applied for the 83 construction of field effect transistors. 44 The reported spatial 84 resolution was a remarkable 2.7 µm, and interestingly it is 85 dependent on the AC voltage frequency and amplitude, with Please do not adjust margins Please do not adjust margins device providing topside illumination of an a-Si thin layer with a p-i-n (p-type, intrinsic, n-type) structure deposited on a monocrystalline silicon wafer as the photoelectrode.…”

Optoelectronic tweezers: a versatile toolbox for nano-/micro-manipulation

“…OET has been used to manipulate and assemble a variety of nanomaterials, including semiconductor and metallic nanowires, 84,87,122,123 carbon nanotubes, 124,125 graphene nanoplatelets, 100,126,127 conductive nanoparticles, 83,86,114,115,127,128 and metal ions. [129][130][131][132] The size of the manipulated nanoparticles ranges from a few tens of nanometers to a few hundreds of nanometers. Fig.…”

“…115,128 Another method to fabricate electrodes with an OET is using light-activated 'virtual electrodes' to deposit metal ions through an electrochemical reaction. [129][130][131][132] In this case, metal ions in the liquid medium react with the trapped electrons on the surface of the illuminated region in an OET. Under the effects of dynamic electron transfer, 132 the metal ions are reduced to atoms, which then crystallize and form metallic structures.…”

A Review on Optoelectrokinetics-Based Manipulation and Fabrication of Micro/Nanomaterials

“…An optically-induced electrochemical reaction and deposition scheme was presented to enable dynamic, rapid and mask-free fabrication of microelectrodes [75][76][77][78][79]. When the OEK chip was illuminated by optically-projected images, an electrical field would be produced in the illuminated area due to the creation of electron-hole pairs.…”