Influence of Substrate, Additives, and Pulse Parameters on Electrodeposition of Gold Nanoparticles from Potassium Dicyan
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AUNPS are of much interest due to their superior conductivity, biocompatibility, adjustable optical and electrical behavior, and high catalytic effects.[1,2] Conductive substrates coated with AuNPs are usable in electronic and biochemical sensors and electrodes owing to their excellent electrocatalytic behavior.[2–7] An example is AuNP-ITO which is used for making electrodes.[8] This material has good electrical conductivity, high stability, and capability to promote heterogeneous electron transfer.[2,3,9] Applications of AuNP-ITO include the electro-oxidation of uric acid, ascorbic acid, dopamine, norepinephrine, epinephrine,[10] and nitric oxide.[11] AuNPITO provides a biocompatible matrix for immobilization of hemoglobin (Hb),[12] effective H2O2 reduction catalysis with stable reproducibility,[12] myoglobin (Mb) immobilization, and mediator-free H2O2 sensor development[13] with promotion of the electrocatalytic activity of three-dimensional monolayer of 3-mercaptopropionic acid (MPA) assembled on AuNP-ITOs,[14] electrochemical response of the hydroquinone and p-aminophenol in phosphate buffer solutions[15] and electrochemical measurement of biomolecules such as simultaneous electrochemical determination of guanosine/guanosine-5¢-triphosphate, adenosine/adenosine-5¢triphosphate, and dopamine/serotonin.[4,16] Cu is the most common interconnecting material of the electronic circuits. Gold nanoparticles deposited PARISA VAHDATKHAH, Graduate Student, and SAYED KHATIBOLESLAM SADRNEZHAAD, Professor, are with the Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Tehran, Iran. Contact email: [email protected] Manuscript submitted August 19, 2013. METALLURGICAL AND MATERIALS TRANSACTIONS B
onto Cu and ITO result in a collection of many useful properties like low electrical resistivity,[17] Cu-to-Cu adhesive bonding,[18] and transparent conductive behavior.[19] These electrodes are therefore usable in many diverse applications.[19] Several methods have previously been used for attachment of AuNPs onto ITO.[3,7,8] General strategy has been self-assembly of binder molecules onto ITO. This method has been influenced by catalytic property and conductive behavior of the NPs.[8] To overcome this difficulty, seed-mediated growth has been developed.[4,8] This technique has, however, been complex and timeconsuming. RF-sputtering[3] and nano-sphere lithography[20] have also been practiced to attach AuNPs onto an ITO substrate. Another simple, powerful, and cost effective way for attachment of AuNPs onto a substrate layer has been utilization of the electrochemical method.[7,9,21] In previous trials, cyclic voltammetry, potential-sweeping, and potential-step modes have been used.[6,7,9,22] The formation of gold ion complex with cysteine (2-amino-3mercaptopropionic acid) has, for example, resulted in enhancement of the number of the electrodeposited AuNPs with bumpy, thorny or dendritic shapes.[9,23] Pulsating current can, however, result in smoother, brighter, finer, and less po
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