Effect Of Electric Current On CdSe/ZnS Core/Shell Quantum Dot Photobleaching At The Single Particle Level

Quantum dots(QDs)have attracted more attention due to the unique optical properties.Characterizing the optical properties is of great importance to the fields such as bioanalysis and semiconductor science and technology.So far,the effects of composition,morphology,aggregation,and medium on QDs optical properties have been investigated.Unfortunately,the effect of current on QDs optical properties has not been studied yet.Herein,the current inducing CdSe/ZnS core/shell QDs rapid bleaching was discovered at single particle level and the possible mechanism was proposed.The bleaching of CdSe/ZnS core/shell QDs onto the electrodes was investigated with the current on/off at single particle level.It was found the current induced rapid bleaching of QDs no matter what sizes,surface groups modified onto the QDs,the size of the groups were.As a contrast,the QDs in the solution did not show the current inducing fast bleaching.Meanwhile,the effects of the current on the fluorescence intensity and spectral shift of the QDs onto the electrodes were studied at single particle level.Based on the effects of light irradiation or current alone on the bleaching,the conclusion that light irradiation and current synergistically induce the fast bleaching of CdSe/ZnS core/shell QDs can be drawn.It was found that the bigger the current and the light intensity are,the faster the bleaching rate is.The possible mechanism for the fast bleaching induced by the current was proposed,and further experiments verified the mechanism.