• 文献标题:   Correlated Optical-Electrochemical Measurements Reveal Bidirectional Current Steps for Graphene Nanoplatelet Collisions at Ultramicroelectrodes
  • 文献类型:   Article
  • 作  者:   PENDERGAST AD, RENAULT C, DICK JE
  • 作者关键词:  
  • 出版物名称:   ANALYTICAL CHEMISTRY
  • ISSN:   0003-2700 EI 1520-6882
  • 通讯作者地址:  
  • 被引频次:   11
  • DOI:   10.1021/acs.analchem.0c04409
  • 出版年:   2021

▎ 摘  要

Single-entity electrochemistry has emerged as a powerful tool to study the adsorption behavior of single nanoscale entities one-at-a-time on an ultramicroelectrode surface. Classical single-entity collision studies have focused on the behavior of spherical nanoparticles or entities where the orientation of the colliding entity does not impact the electrochemical response. Here, we report a detailed study of the collision of asymmetric single graphene nanoplatelets onto ultramicroelectrodes. The collision of conductive graphene nanoplatelets on biased ultramicroelectrode surfaces can be observed in an amperometric i-t trace, revealing a variety of current transients (both positive and negative steps). To elucidate the dynamics of nanoplatelet adsorption processes and probe response heterogeneity, we correlated the collision events with optical microscopy. We show that positive steps are due to nanoplatelets coming into contact with the ultramicroelectrode, making an electrical connection, and adsorbing partly on the glass surrounding the ultramicroelectrode. Negative steps occur when nanoplatelets adsorb onto the glass without an electrical connection, effectively blocking flux of ferrocenemethanol to the ultramicroelectrode surface. These measurements allow rigorous quantification of current transients and detailed insights into the adsorption dynamics of asymmetric objects at the nanoscale.