Dynamic magnetic field alignment and polarized emission of semiconductor nanoplatelets in a liquid crystal polymer

Dahin Kim; Dennis Ndaya; Reuben Bosire; Francis K Masese; Weixingyue Li; Sarah M Thompson; Cherie R Kagan; Christopher B Murray; Rajeswari M Kasi; Chinedum O Osuji

doi:10.1038/s41467-022-30200-2

Dynamic magnetic field alignment and polarized emission of semiconductor nanoplatelets in a liquid crystal polymer

Nat Commun. 2022 May 6;13(1):2507. doi: 10.1038/s41467-022-30200-2.

Authors

Dahin Kim¹, Dennis Ndaya^{2

3}, Reuben Bosire², Francis K Masese², Weixingyue Li⁴, Sarah M Thompson⁵, Cherie R Kagan^{4

5

6}, Christopher B Murray^{4

6}, Rajeswari M Kasi^{2

3}, Chinedum O Osuji⁷

Affiliations

¹ Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
² Department of Chemistry, University of Connecticut, Storrs, CT, 06269, USA.
³ Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT, 06269, USA.
⁴ Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA.
⁵ Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
⁶ Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
⁷ Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA. cosuji@seas.upenn.edu.

Abstract

Reconfigurable arrays of 2D nanomaterials are essential for the realization of switchable and intelligent material systems. Using liquid crystals (LCs) as a medium represents a promising approach, in principle, to enable such control. In practice, however, this approach is hampered by the difficulty of achieving stable dispersions of nanomaterials. Here, we report on good dispersions of pristine CdSe nanoplatelets (NPLs) in LCs, and reversible, rapid control of their alignment and associated anisotropic photoluminescence, using a magnetic field. We reveal that dispersion stability is greatly enhanced using polymeric, rather than small molecule, LCs and is considerably greater in the smectic phases of the resulting systems relative to the nematic phases. Aligned composites exhibit highly polarized emission that is readily manipulated by field-realignment. Such dynamic alignment of optically-active 2D nanomaterials may enable the development of programmable materials for photonic applications and the methodology can guide designs for anisotropic nanomaterial composites for a broad set of related nanomaterials.

Abstract

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