Emergent quantum phenomena in electronically coupled two-dimensional heterostructures are central to next-generation optical, electronic, and quantum information applications. Tailoring electronic band gaps in coupled heterostructures would permit control of such phenomena and is the subject of significant research interest. Two-dimensional polymers (2DPs) offer a compelling route to tailored band structures through the selection of molecular constituents. However, despite the promise of synthetic flexibility and electronic design, fabrication of 2DPs that form electronically coupled 2D heterostructures remains an outstanding challenge. Here, we report the rational design and optimized synthesis of electronically coupled semiconducting 2DP/2D transition metal dichalcogenide van der Waals heterostructures, demonstrate direct exfoliation of the highly crystalline and oriented 2DP films down to a few nanometers, and present the first thickness-dependent study of 2DP/MoS2 heterostructures. Control over the 2DP layers reveals enhancement of the 2DP photoluminescence by two orders of magnitude in ultrathin sheets and an unexpected thickness-dependent modulation of the ultrafast excited state dynamics in the 2DP/MoS2 heterostructure. These results provide fundamental insight into the electronic structure of 2DPs and present a route to tune emergent quantum phenomena in 2DP hybrid van der Waals heterostructures.
KAUST Repository Item: Exported on 2020-12-14
Acknowledgements: We thank Yi Liu, Victoria Norman, Greg Stiehl, Shilong Zhao, Lindsey Young, and Sheng Wang. We also thank Ming-Yang Li and Lain-Jong Li at King Abdullah University of Science and Technology (KAUST) for providing the transition metal dichalcogenide substrates. This work was supported by the Army Research Office for a Multidisciplinary University Research Initiatives (MURI) award under grant W911NF15-1-0447. A.M.E. and I.C. were supported by the Ryan Fellowship and the Northwestern University International Institute for Nanotechnology and by NSF Graduate Research Fellowships [A.M.E. under grant DGE-1324585; I.C. under grant DGE-1842165]. J.L.B. and H.L. acknowledge support
from the College of Science, University of Arizona. This research used resources of the Advanced Light Source, a DOE Office of Science User Facility under contract no. DE-AC02- 05CH11231. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DEAC02−05CH11231.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.