Dynamics and kinetics study of individual QD at UME surface

In the last decade, fluorescent semiconductor nanoparticles (quantum dots, QD) have gained increasing interest in various applications such as photovoltaic or bioanalytics. Although there have been several studies on QD redox-... [ view full abstract ]

In the last decade, fluorescent semiconductor nanoparticles (quantum dots, QD) have gained increasing interest in various applications such as photovoltaic or bioanalytics. Although there have been several studies on QD redox- and electrochemistry like performed by Amelia et al. [1], the knowledge of dynamics and kinetics of individual QDs at electrode surfaces is still limited, because we cannot distinguish between electrochemically active and non active QDs in a heterogeneous mixture. 

Adsorption and desorption of nanoparticles on microelectrodes already has been subject of investigation [2]. In order to obtain more detailed information, the electrochemical reactivity of single particles on the surface of an ultra microelectrode is observed via single molecule spectroscopy and time resolved fluorescence spectroscopy. These methods allow an effective observation of adsorption and desorption of QDs to the electrode surface, and furthermore kinetics of QD modification or degradation processes. In order to enable a correlation of optically registered events and electrochemical events, the diameter of the UME is matched to the size of the optical observation volume, typically around 1 mm. For data evaluation, cross correlation analysis is employed.

[1] M. Amelia, C. Lincheneau, S. , A.Credi,Electrochemical properties of CdSe and CdTe quantum dos, Chem.Soc. Rev., 2012, 41, 5728-5743.

[2] A. Boika, S. N. Thotgaard, A. J.Bard, Monitorng the electrophoretic migration and adsorption of single Insulating Nanoparticles at Ultramicroelectrodes,J. Phys. Chem. B., 2013, 117,4371-4380