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Correlated fluorescence blinking in two-dimensional semiconductor heterostructures


‘Blinking’, or ‘fluorescence intermittency’, refers to a random switching between ‘ON’ (bright) and ‘OFF’ (dark) states of an emitter; it has been studied widely in zero-dimensional quantum dots1 and molecules2,3, and scarcely in one-dimensional systems4,5. A generally accepted mechanism for blinking in quantum dots involves random switching between neutral and charged states6,7 (or is accompanied by fluctuations in charge-carrier traps8), which substantially alters the dynamics of radiative and non-radiative decay. Here, we uncover a new type of blinking effect in vertically stacked, two-dimensional semiconductor heterostructures9, which consist of two distinct monolayers of transition metal dichalcogenides (TMDs) that are weakly coupled by van der Waals forces. Unlike zero-dimensional or one-dimensional systems, two-dimensional TMD heterostructures show a correlated blinking effect, comprising randomly switching bright, neutral and dark states. Fluorescence cross-correlation spectroscopy analyses show that a bright state occurring in one monolayer will simultaneously lead to a dark state in the other monolayer, owing to an intermittent interlayer carrier-transfer process. Our findings suggest that bilayer van der Waals heterostructures provide unique platforms for the study of charge-transfer dynamics and non-equilibrium-state physics, and could see application as correlated light emitters in quantum technology.

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Figure 1: Fluorescence blinking in a loosely contacted WS2/MoSe2 2D bilayer heterostructure.
Figure 2: The IICT model of fluorescence blinking in 2D heterostructures.
Figure 3: Variation in trion and exciton emission from heterostructures over time.
Figure 4: Fluorescence cross-correlation spectroscopy analyses of a blinking WS2/MoSe2 bilayer heterostructure.


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We thank Professor C.-D. Ohl for providing us with a high-speed camera for dynamical fluorescence imaging. Q.X. acknowledges the support of the Singapore National Research Foundation through an Investigatorship award (NRF-NRFI2015-03), and the Singapore Ministry of Education via two AcRF Tier 2 grants (MOE2012-T2-2-086 and MOE2015-T2-1-047). W.L. acknowledges scholarship support from the China Scholarship Council (no. 201506160035).

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Authors and Affiliations



W.X. and Q.X. designed the research; W.X., W.L. and X.L. prepared the heterostructures and carried out steady-state/transient fluorescence spectroscopy measurements and correlation measurements; J.F.S., W.Z., T.R. and D.V.S. performed transient absorption spectroscopy measurements; W.X., W.L., X.L., W.Z., J.F.S., D.V.S., C.D., W.G. and Q.X. analysed the data; and W.X., W.L. and Q.X. wrote the manuscript. All authors commented on the manuscript.

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Correspondence to Qihua Xiong.

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The authors declare no competing financial interests.

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Reviewer Information Nature thanks X. Cui and A. Malko for their contribution to the peer review of this work.

Supplementary information

Supplementary Information

This file contains Supplementary Text, Supplementary Figures 1-16 and Supplementary References. (PDF 5862 kb)

High speed dynamic fluorescence imaging of the WS2 component in the WS2/MoSe2 heterostructure

High speed dynamic fluorescence imaging of the WS2 component in the WS2/MoSe2 heterostructure. (AVI 5047 kb)

High speed dynamic fluorescence imaging of the MoSe2 component in the WS2/MoSe2 heterostructure

High speed dynamic fluorescence imaging of the MoSe2 component in the WS2/MoSe2 heterostructure. (AVI 8356 kb)

Dynamic fluorescence imaging of the WS2 component in a MoS2/WS2 heterostructure acquired with a color CCD camera

Dynamic fluorescence imaging of the WS2 component in a MoS2/WS2 heterostructure acquired with a color CCD camera. (AVI 1846 kb)

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Xu, W., Liu, W., Schmidt, J. et al. Correlated fluorescence blinking in two-dimensional semiconductor heterostructures. Nature 541, 62–67 (2017).

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