Fluorescence spectroelectrochemistry of multilayer film assembled CdTe quantum dots controlled by applied potential in aqueous solution

The change of the photoluminescence (PL) property of CdTe quantum dot (QD) assembled multilayers along with applied potential has been investigated in aqueous solution. By using the in situ fluorescence spectroelectrochemistry technique, we examined the PL property of QDs upon applying potentials under different atmosphere media, in air and in nitrogen. It was found that when the sample was under nitrogen or exposed to air, the luminescence of QDs bear quenching by adding positive potentials. On the contrary, while applying negative potentials, the luminescence of QD was weakened only in the air condition. It seemed that the luminescence of CdTe QDs was hardly affected by the potentials under nitrogen. On the basis of the phenomena, electrochemistry and X-ray photoelectron spectroscopy (XPS) measurements were then performed to explain the possible origins of PL changes. The results clearly indicated that the variation of surface structure of QDs affected the PL property of CdTe QDs significantly.