|Title||In Situ Spectroelectrochemical Fluorescence Microscopy for Visualizing Interfacial Structure and Dynamics in Self-assembled Monolayers|
|Publication Type||Book Chapter|
|Year of Publication||2017|
|Authors||Casanova-Moreno, J, Yu, ZLandis, Massey-Allard, J, Ditchburn, B, Young, JF, Bizzotto, D|
|Book Title||Luminescence in Electrochemistry|
|Publisher||Springer International Publishing|
In situ analysis of electrochemical interfaces modified with molecular adsorbates using fluorescence microscopy is outlined. The fluorescence intensity from the fluorophore-modified adsorbate is strongly quenched when the separation of the fluorophore from the metal electrode surface is decreased below 200 nm. The theory describing this important characteristic is outlined with emphasis on the lifetime and far-field intensity of the fluorophore as a function of the separation from the metal. A number of examples are given in which fluorescence microscopy is used to study surfaces modified with the self-assembled monolayers (SAMs) composed of either alkylthiols, peptides, or DNA. The ability to interrogate both the lateral and axial distributions of the adsorbed monolayers within the micron scale optical resolutions is highlighted. The influence of the electrode potential (or charge) on the fluorescence images is shown for the reductive or oxidative removal of the adsorbate. The preparation of modified electrode surfaces is also reviewed, illustrating the influence of surface crystallography on the resulting surface modi- fication or thiol exchange processes. Preliminary results of a DNA SAM studied using 2-photon fluorescence lifetime imaging microscopy are presented, demon- strating the measurement of lifetime distributions and its correspondence with the theory. In situ spectroelectrochemical fluorescence microscopy is thus shown to be useful in studying the electrochemical interface in terms of its homogeneity of modification, the structure in the axial direction away from the electrode surface and the influence of charge (or potential) on the dynamics of the interface.