Controlling exciton flow in colloidal nanomaterials (IMAGE)
Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, CAS
Caption
(a) The normalized contour map of emission spectra when the nanomaterial mixture is coated in a capillary tube. White dashed lines indicate the thresholds of red lasing (acceptor) and green lasing (donor). Top inset: photography images corresponding to spontaneous emission, acceptor lasing and dual lasing, respectively. (b) Lasing's integrated intensity as a function of the pump fluence for the donors (green dots/line) and the acceptors (red dots/line). Three emission regimes (i.e. spontaneous emission, acceptor lasing and dual lasing) are shaded in grey, light red and light green, respectively. (c) The normalized integrated intensity of donors' spontaneous emission. In the acceptor lasing regime, excitons are transferred to acceptors more efficiently, therefore the donors' spontaneous emission increases sub-linearly with respect to excitation power. Then it increases super-linearly when entering dual lasing regime (d) The calculated exciton outflowing efficiency in the donor. Three distinct efficiencies (50%, 90% and 2%) are achieved and controlled by excitation fluence corresponding to spontaneous emission, acceptor lasing and dual lasing regime. (e) Illustration of controlling exciton flow by stimulated emission. The fundamental mechanism is to control the density of the excited donors N1D and the unexcited (ground state) acceptors N0A by utilizing super high exciton recombination rate of stimulate emission.
Credit
Junhong Yu, Manoj Sharma, Ashma Sharma, Savas Delikanli, Hilmi Volkan Demir, Cuong Dang
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