Dependence of electrochemical charging of gold nanoparticle monolayer films on counterion proximity

作者：Li, Wanzhen; Su, Bin^*

来源：Electrochemistry Communications, 2013, 33: 27-30.

DOI：10.1016/j.elecom.2013.04.008

• Counterion proximity
• Electrochemical charging
• Nanoparticle films
• Charge compensation
• Ion permeation

Herein we report the nontrivial effect of counterion size on the electrochemical charging of gold nanoparticle (or called MPC) monolayer films in aqueous electrolyte solutions. The electrochemical charging response was observed with relatively small counterions (e.g., BF4-, ClO4- and PF6-) but not large ones like bis(trifluoromethylsulfonyl) amide (Tf2N-), tetrakis(pentafluorophenyl)borate (TB-) or bis(triphenylphosphoranylidene) (BA(+)). This effect was explained by the proximity of counterions to the MPC surface, which determines whether the electronic charges on MPCs can be effectively compensated by formation of ion pairs. Only small counterions are permitted to approach the MPC surface by permeating the alkanethiolate layer to achieve a sufficient charge compensation. In contrast, big ions are sterically excluded and thus disfavor the electrochemical charging. This finding helps in further understanding the ion-coupled electrochemical charging mechanism of nanoparticle films.

• 出版日期2013-8
• 单位浙江大学