부산대학교 도서관

A new class of optoelectronic nanodevices consisting of 0D semiconductor nanocrystals and 2D single graphene layers is attracting much attention. In particular, such a system may be used to investigate and control the transfer of energy and charge in low-dimensional systems. To this end, the fluorescence dynamics of individual colloidal quantum dots (QDs) on graphene are investigated on both the 10–9–10–8s time scale (fluorescence lifetime) and the 100–102s time scale (blinking statistics) in this paper. We find that (i) a nonradiative energy transfer rate of ≈5 × 108s–1is obtained from the reduced lifetimes of QDs on graphene as opposed to those on insulating substrates such as glass; (ii) QDs still exhibit fluorescence intermittency (“blinking”) on graphene; (iii) the cumulative distribution functions of the “off” times may be described by power-law statistics; (iv) QD coupling to graphene increases the time spent in the “on” state while the time spent in the “off” state remains relatively unchanged; and (v) the fluorescence emission spectrum of the QDs is practically unaltered by the QD–graphene coupling.