Influence of Oxygen on Single Molecule Blinking

The influence of ambient oxygen on blinking (on–off transitions) of individual terrylenediimide (TDI) molecules is investigated by confocal microscopy. The authors show that the “on-times”—during which the fluorescence intensity is above a certain threshold—are shortened significantly in ambient air compared to in nitrogen. The “off-times” are virtually unaffected. In addition, it is shown that single TDI molecules embedded in a polymer film show much longer “on-times” and fewer “blinks” than those adsorbed on a glass surface.