J. Zultak, A. Raja, A. Montoya–Castillo, X-X. Zhang, Z. Ye, C. Roquelet, D. A. Chenet, A. M. van der Zande, P. Huang, J. Hone, D. R. Reichman, L. E. Brus, T. F. Heinz DTU Nanotech, Technical University of Denmark, Ørsteds Plads Building 345B, DK-2800 Kongens Lyngby, Denmark  Understanding the dynamics of charge carriers at nanoscale interfaces is an important field of research both from the fundamental science and technological applications perspective. Interactions between semiconductor quantum dots (QD), a prototypical 0D system, and 2D van der Waals materials have been getting a lot of attention in recent research2,3. Here, we report the observation of efficient non-radiative energy transfer (NRET) from core-shell QD to graphene and MoS2 via photoluminescence quenching of single QD emission on monolayer materials and direct measurement of decay rates through time-resolved photoluminescence on single layer to bulk 2D crystals1. Our measurements reveal opposite trends with thickness of the 2D materials for the rate of NRET to graphene and MoS2. The contrasting behaviours are explained in terms of the competition between the screening of the QD dipole and the dissipation of the electric field in the 2D material.[1] Raja, A. et al. Energy transfer from quantum dots to graphene and MoS2: The role of absorption and screening in two-dimensional materials. Nano Lett. (2016). doi:10.1021/acs.nanolett.5b05012 [2] Chen, Z., Berciaud, S., Nuckolls, C., Heinz, T. F. & Brus, L. E. Energy transfer from individual semiconductor nanocrystals to graphene. ACS Nano 4, 2964–2968 (2010). [3] Prins, F., Goodman, A. J. & Tisdale, W. A. Reduced dielectric screening and enhanced energy transfer in single- and few-layer MoS2. Nano Lett. 14, 6087–6091 (2014).  Johanna Zultak is a PhD student at DTU Nanotech working on stacks of various 2D materials for electronic devices fabrication and characterization. She received his Master degree in Physics from EPFL in 2014. |
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