Photoluminenscence blinking dynamics of colloidal quantum dots in the presence of controlled external electron traps

The effect of the external charge trap on the photoluminescence blinking dynamics of individual colloidal quantum dots is investigated with a series of colloidal quantum dot-bridge-fullerene dimers with varying bridge lengths, where the fullerene moiety acts as a well-defined, well-positioned external charge trap. It is found that charge transfer followed by charge recombination is an important mechanism in determining the blinking behavior of quantum dots when the external trap is properly coupled with the excited state of the quantum dot, leading to a quasi-continuous distribution of 'on' states and an early fall-off from a power-law distribution for both 'on' and 'off' times associated with quantum dot photoluminescence blinking. The effect of external charge traps on the photoluminescence blinking of colloidal quantum dots is investigated by single-molecule spectroscopy using a series of colloidal quantum dot-bridge-fullerene dimers with varying bridge lengths and with the fullerene moiety acting as a well-defined, well-positioned, external charge trap.