Determination of the In-Plane Exciton Radius in 2D CdSe Nanoplatelets via Magneto-optical Spectroscopy

Alexandra Brumberg, Samantha M. Harvey, John P. Philbin, Benjamin T. Diroll, Byeongdu Lee, Scott A. Crooker, Michael R. Wasielewski, Eran Rabani, Richard D. Schaller

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Colloidal, two-dimensional semiconductor nanoplatelets (NPLs) exhibit quantum confinement in only one dimension, which results in an electronic structure that is significantly altered compared to that of other quantum-confined nanomaterials. Whereas it is often assumed that the lack of quantum confinement in the lateral plane yields a spatially extended exciton, reduced dielectric screening potentially challenges this picture. Here, we implement absorption spectroscopy in pulsed magnetic fields up to 60 T for three different CdSe NPL thicknesses and lateral areas. Based on diamagnetic shifts, we find that the exciton lateral extent is comparable to NPL thickness, indicating that the quantum confinement and reduced screening concomitant with few-monolayer thickness strongly reduces the exciton lateral extent. Atomistic electronic structure calculations of the exciton size for varying lengths, widths, and thicknesses support the substantially smaller in-plane exciton extent.

Original languageEnglish
Pages (from-to)8589-8596
Number of pages8
JournalACS nano
Volume13
Issue number8
DOIs
Publication statusPublished - Aug 27 2019

Keywords

  • Diamagnetic shift
  • electronic structure
  • exciton size
  • nanoplatelets
  • quantum confinement

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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    Brumberg, A., Harvey, S. M., Philbin, J. P., Diroll, B. T., Lee, B., Crooker, S. A., Wasielewski, M. R., Rabani, E., & Schaller, R. D. (2019). Determination of the In-Plane Exciton Radius in 2D CdSe Nanoplatelets via Magneto-optical Spectroscopy. ACS nano, 13(8), 8589-8596. https://doi.org/10.1021/acsnano.9b02008