Abstract

Intrinsically directional light emitters are potentially important for applications in photonics including lasing and energy-efficient display technology. Here, we propose a new route to overcome intrinsic efficiency limitations in light-emitting devices by studying a CdSe nanoplatelets monolayer that exhibits strongly anisotropic, directed photoluminescence. Analysis of the two-dimensional k-space distribution reveals the underlying internal transition dipole distribution. The observed directed emission is related to the anisotropy of the electronic Bloch states governing the exciton transition dipole moment and forming a bright plane. The strongly directed emission perpendicular to the platelet is further enhanced by the optical local density of states and local fields. In contrast to the emission directionality, the off-resonant absorption into the energetically higher 2D-continuum of states is isotropic. These contrasting optical properties make the oriented CdSe nanoplatelets, or superstructures of parallel-oriented platelets, an interesting and potentially useful class of semiconductor-based emitters.

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Acknowledgements

R.S., U.W. and A.W.A acknowledge DFG grants WO477–1/32 and AC290-1/1 and 2/1. J.I.C. acknowledges support from MINECO project CTQ2014-60178-P and UJI project P1-1B2014-24, M.A. from the CHEMREAGENTS program and A.A. from BRFFI grant no. X16M-020.

Author information

Author notes

    • Riccardo Scott
    •  & Jan Heckmann

    These authors contributed equally to this work.

Affiliations

  1. Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, Berlin 10623, Germany

    • Riccardo Scott
    • , Jan Heckmann
    • , Nina Owschimikow
    • , Ulrike Woggon
    • , Nicolai B. Grosse
    •  & Alexander W. Achtstein
  2. Research Institute for Physical Chemical Problems of Belarusian State University, Minsk 220006, Belarus

    • Anatol V. Prudnikau
    • , Artsiom Antanovich
    • , Aleksandr Mikhailov
    •  & Mikhail Artemyev
  3. Departament de Química Física i Analítica, Universitat Jaume I, Castelló de la Plana E-12080, Spain

    • Juan I. Climente

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Contributions

J.H., R.S., A.V.P. and N.G. performed measurements. A.V.P., A.A., A.M. and M.A. made samples. J.H., R.S., N.B.G. and A.W.A. analysed, modelled and interpreted the data. J.I.C. contributed theoretical interpretation. J.H., R.S., N.B.G, J.I.C., N.O. and A.W.A wrote the manuscript. U.W. contributed to discussions.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Alexander W. Achtstein.

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DOI

https://doi.org/10.1038/nnano.2017.177

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