Anisotropic Photoluminescence from Isotropic Optical Transition Dipoles in Semiconductor Nanoplatelets

Xuedan Ma*, Benjamin T. Diroll, Wooje Cho, Igor Fedin, Richard D. Schaller, Dmitri V. Talapin, Gary P. Wiederrecht

*Corresponding author for this work

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Many important light-matter coupling and energy-transfer processes depend critically on the dimensionality and orientation of optical transition dipoles in emitters. We investigate individual quasi-two-dimensional nanoplatelets (NPLs) using higher-order laser scanning microscopy and find that absorption dipoles in NPLs are isotropic in three dimensions at the excitation wavelength. Correlated polarization studies of the NPLs reveal that their emission polarization is strongly dependent on the aspect ratio of the lateral dimensions. Our simulations reveal that this emission anisotropy can be readily explained by the electric field renormalization effect caused by the dielectric contrast between the NPLs and the surrounding medium, and we conclude that emission dipoles in NPLs are isotropic in the plane of the NPLs. Our study presents an approach for disentangling the effects of dipole degeneracy and electric field renormalization on emission anisotropy and can be adapted for studying the intrinsic optical transition dipoles of various nanostructures.

Original languageEnglish (US)
Pages (from-to)4647-4652
Number of pages6
JournalNano letters
Volume18
Issue number8
DOIs
StatePublished - Aug 8 2018

Keywords

  • CdSe/CdS core/shell nanoplatelets
  • electric field renormalization effect
  • emission anisotropy
  • higher-order Bessel-Gauss beam
  • optical transition dipole

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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