{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T21:04:34Z","timestamp":1776287074824,"version":"3.50.1"},"reference-count":38,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2013,3,12]],"date-time":"2013-03-12T00:00:00Z","timestamp":1363046400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Catalysts"],"abstract":"<jats:p>Gold nanostars of ~70 nm tip to tip distances were synthesized by a seed mediated method and covalently self-assembled on 1,5-pentanedithiol modified electrodes. Electron transfer kinetics at the AuNS\/dithiol modified electrodes were studied as a function of AuNS surface density which was varied by increasing their self-assembly time from 8 h, 16 h, 24 h to 32 h. Excellent electrocatalytic properties of AuNSs were observed toward electrochemistry of [Fe(CN)6]4\u2212\/3\u2212 redox couple. The apparent heterogeneous electron transfer constant, ket, has progressively increased with the surface density of AuNSs bonded to the electrodes from 0.65 \u00d7 10\u22125 cm s\u22121 (8 h), 1.47 \u00d7 10\u22125 cm s\u22121 (16 h), 3.95 \u00d7 10\u22125 cm s\u22121 (24 h) to an excellent 85.0 \u00d7 10\u22125 cm s\u22121 (32 h). Electrochemical charging of nanostars was confirmed, for the first time, by 79 times increase of double layer capacitance, Cdl, from 0.34 \u00b5F (8 h) to 27 \u00b5F (32 h). The electrochemical charging of AuNSs had also a strong influence on the electron tunneling process through the 1,5PDT molecules being more efficient at dense layers of AuNSs. The tunneling parameter, \u03b2, has decreased from 1.13 \u00c5\u22121 (16 h) to 0.50 \u00c5\u22121 (32 h). The AuNSs were chemically stable toward [Fe(CN)6]4\u2212\/3\u2212 showing no change in shape after electrochemical measurements.<\/jats:p>","DOI":"10.3390\/catal3010288","type":"journal-article","created":{"date-parts":[[2013,3,13]],"date-time":"2013-03-13T04:22:17Z","timestamp":1363148537000},"page":"288-309","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":28,"title":["Electron Transfer at Gold Nanostar Assemblies: A Study of Shape Stability and Surface Density Influence"],"prefix":"10.3390","volume":"3","author":[{"given":"Mariana","family":"Chirea","sequence":"first","affiliation":[{"name":"Chemistry and Biochemistry Department, Faculty of Sciences, Universidade do Porto, Rua Campo Alegre 687, 4169-007, Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2013,3,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1021\/cr900137k","article-title":"Prospects of colloidal nanocrystals for electronic and optoelectronic applications","volume":"110","author":"Talapin","year":"2010","journal-title":"Chem. Rev."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1323","DOI":"10.1126\/science.272.5266.1323","article-title":"Coulomb staircase at room temperature in a self-assembled molecular nanostructure","volume":"272","author":"Andres","year":"1996","journal-title":"Science"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"13077","DOI":"10.1021\/jp9018712","article-title":"Size-dependent electrochemical properties of gold nanorods","volume":"113","author":"Chirea","year":"2009","journal-title":"J. Phys. Chem. C"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"9478","DOI":"10.1021\/jp912231s","article-title":"Density-dependent electrochemical properties of vertically aligned gold nanorods","volume":"114","author":"Chirea","year":"2010","journal-title":"J. Phys. Chem. C"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"11121","DOI":"10.1021\/la901421m","article-title":"Formation of efficient electron transfer pathways by adsorbing gold nanoparticles to self-assembled monolayer modified electrodes","volume":"25","author":"Shein","year":"2009","journal-title":"Langmuir"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"21175","DOI":"10.1039\/c1cp21996k","article-title":"Electrochemical charge transfer mediated by metal nanoparticles and quantum dots","volume":"13","author":"Gabriela","year":"2011","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"5861","DOI":"10.1021\/la300404r","article-title":"Transparent gold as a platform for adsorbed Protein Spectroelectrochemistry: Investigation of cytocrom c and azurin","volume":"28","author":"Ashur","year":"2012","journal-title":"Langmuir"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1539","DOI":"10.1021\/la0356349","article-title":"Metallic contact formation for molecular electronics: interactions between vapor-deposited metals and self-assembled monolayers of Conjugated mono- and dithiols","volume":"20","author":"Frank","year":"2004","journal-title":"Langmuir"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1021\/jp908821b","article-title":"1,6-Hexanedithiol self-assembled monolayers on Au(111) investigated by electrochemical, spectroscopic, and molecular mechanics methods","volume":"114","author":"Qu","year":"2010","journal-title":"J. Phys. Chem. C"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1002\/smll.200700623","article-title":"Self-assembled-monolayer formation of long alkanedithiols in molecular junctions","volume":"4","author":"Akkerman","year":"2008","journal-title":"Small"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Chah, S., Fendler, J.H., and Yi, J. (2002). In-situ analysis of step-wise self-assembled 1,6Hexanedithiol multilayers by surface plasmon resonance measurements. Chem. Commun., 2094\u20132095.","DOI":"10.1039\/b206817f"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1126\/science.278.5336.252","article-title":"Conductance of a molecular junction","volume":"278","author":"Reed","year":"1997","journal-title":"Science"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"571","DOI":"10.1126\/science.1064354","article-title":"Reproducible measurements of single molecule conductivity","volume":"294","author":"Cui","year":"2001","journal-title":"Science"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"5189","DOI":"10.1021\/la0529815","article-title":"In situ scanning tunneling microscopy of 1,6-hexanedithiol, 1,9-nonanedithiol, 1,2-benzenedithiol, and 1,3-benzenedithiol adsorbed on Pt(111) electrodes","volume":"22","author":"Yang","year":"2006","journal-title":"Langmuir"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"12072","DOI":"10.1021\/ja302602b","article-title":"Tunneling characteristics of Au-alkanedithiol-Au junctions formed via nanotransfer printing (nTP)","volume":"134","author":"Niskala","year":"2012","journal-title":"J. Am. Chem. Soc."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"376","DOI":"10.1006\/jcis.2002.8238","article-title":"Electrochemical behavior of Au colloidal electrode through layer-by-layer self-assembly","volume":"248","author":"Lu","year":"2002","journal-title":"J. Colloid Interface Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"17570","DOI":"10.1021\/jp0632135","article-title":"Electrochemical metal deposition on top of an organic monolayer","volume":"110","author":"Qu","year":"2006","journal-title":"J. Phys. Chem. B"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"14943","DOI":"10.1021\/la102559e","article-title":"Tuning size and sensing properties in colloidal gold nanostars","volume":"26","author":"Barbosa","year":"2010","journal-title":"Langmuir"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"18849","DOI":"10.1021\/jp8054747","article-title":"Gold nanostars for surface-enhanced Raman scattering: synthesis, characterization and optimization","volume":"112","author":"Khoury","year":"2008","journal-title":"J. Phys. Chem. C"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"015606","DOI":"10.1088\/0957-4484\/19\/01\/015606","article-title":"High-yield synthesis and optical response of gold nanostars","volume":"19","author":"Kumar","year":"2008","journal-title":"Nanothechnology"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"4616","DOI":"10.1021\/ja809418t","article-title":"Zeptomol detection through controlled ultrasensitive surface-enhanced Raman scattering","volume":"131","author":"Mazzucco","year":"2009","journal-title":"J. Am. Chem. Soc."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"7336","DOI":"10.1021\/jp909253w","article-title":"Surface enhanced Raman scattering using star-shaped gold colloidal nanoparticles","volume":"114","year":"2010","journal-title":"J. Phys. Chem. C"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"8979","DOI":"10.1021\/la2048097","article-title":"Plasmonic properties of single multispiked gold nanostars: Correlating modeling with experiments","volume":"28","author":"Shao","year":"2012","journal-title":"Langmuir"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"6318","DOI":"10.1021\/nn100760f","article-title":"Label-free biosensing based on single gold nanostars as plasmonic transducers","volume":"4","author":"Dondapati","year":"2010","journal-title":"ACS Nano"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"709","DOI":"10.1002\/cphc.201100894","article-title":"Removing polyvinylpyrrolidone from catalytic Pt nanoparticles withouth modification of superficial order","volume":"13","author":"Monzo","year":"2012","journal-title":"Chem. Phys. Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"21808","DOI":"10.1021\/jp0537815","article-title":"Electrochemical characterization of polyelectrolyte\/gold nanoparticle multilayers self-assembled on gold electrodes","volume":"109","author":"Chirea","year":"2005","journal-title":"J. Phys. Chem. B"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"9255","DOI":"10.1021\/jp071067c","article-title":"Catalytic effect of gold nanoparticles self-assembled in multilayered polyelectrolyte films","volume":"111","author":"Chirea","year":"2007","journal-title":"J. Phys. Chem. C"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"20906","DOI":"10.1021\/jp052666r","article-title":"Electrochemistry at chemically assembled single-wall carbon nanotube arrays","volume":"109","author":"Diao","year":"2005","journal-title":"J. Phys. Chem. B"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"7036","DOI":"10.1021\/jp077653n","article-title":"How does the particle density affect the electrochemical behaviour of gold nanoparticle assembly?","volume":"112","author":"Diao","year":"2008","journal-title":"J. Phys. Chem. C"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"3173","DOI":"10.1021\/ja00035a001","article-title":"Electron-transfer kinetics in organized thiol monolayers with attached pentaammine(pyridine)ruthenium redox centers","volume":"114","author":"Finklea","year":"1992","journal-title":"J. Am. Chem. Soc."},{"key":"ref_31","first-page":"56","article-title":"Shape dependence of electron transfer kinetics at nanometer sized films","volume":"1","author":"Chirea","year":"2012","journal-title":"Lett. Appl. Nano Biosci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"11544","DOI":"10.1039\/c1jm10603a","article-title":"Reshaping and LSPR tuning of Au nanostars in the presence of CTAB","volume":"21","year":"2011","journal-title":"J. Mater. Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/j.colsurfa.2010.10.012","article-title":"Thermal stability of gold nanorods in an aqueous solution","volume":"372","author":"Zou","year":"2010","journal-title":"Colloids Surf. A"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"24381","DOI":"10.1021\/jp205052f","article-title":"High rate electrochemical capacitors from three-dimensional arrays of vanadium nitride functionalized carbon nanotubes","volume":"115","author":"Zhang","year":"2011","journal-title":"J. Phys. Chem. C"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2483","DOI":"10.1016\/S0013-4686(00)00354-6","article-title":"Principles and applications of electrochemical capacitors","volume":"45","author":"Carlen","year":"2000","journal-title":"Electrochim. Acta"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"6693","DOI":"10.1021\/la0347859","article-title":"A general method to coat colloidal particles with silica","volume":"19","author":"Graf","year":"2003","journal-title":"Langmuir"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1039\/df9511100055","article-title":"A study of the nucleation and growth processes in the synthesis of colloidal gold","volume":"11","author":"Turkevich","year":"1951","journal-title":"Discuss. Faraday Soc."},{"key":"ref_38","first-page":"20","article-title":"Controlled nucleation for the regulation of the particle size in monodisperse gold suspensions","volume":"241","author":"Frens","year":"1973","journal-title":"Nature"}],"container-title":["Catalysts"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4344\/3\/1\/288\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:45:29Z","timestamp":1760219129000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4344\/3\/1\/288"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2013,3,12]]},"references-count":38,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2013,3]]}},"alternative-id":["catal3010288"],"URL":"https:\/\/doi.org\/10.3390\/catal3010288","relation":{},"ISSN":["2073-4344"],"issn-type":[{"value":"2073-4344","type":"electronic"}],"subject":[],"published":{"date-parts":[[2013,3,12]]}}}