Electrochemical Switching of the Photoluminescence of Single Quantum Dots

The electrochemical response of the photoluminescence from single colloidal quantum dots is investigated. CdSe/CdS and CdSe/ZnS nanocrystals on a bare ITO electrode exhibit weak fluorescence due to efficient energy transfer. This is avoided by adding a spacer layer of ZnO nanocrystals film that enables typical photoluminescence and blinking characteristics. The photoluminescence from the single quantum dots can then be reversibly quenched by electrochemical injection of an electron with a reducing potential.