Size-Dependent Biexciton Quantum Yields and Carrier Dynamics of Quasi-Two-Dimensional Core/Shell Nanoplatelets

Xuedan Ma, Benjamin T. Diroll, Wooje Cho, Igor Fedin, Richard D. Schaller, Dmitri V. Talapin, Stephen K. Gray, Gary P. Wiederrecht, David J. Gosztola

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


Quasi-two-dimensional nanoplatelets (NPLs) possess fundamentally different excitonic properties from zero-dimensional quantum dots. We study lateral size-dependent photon emission statistics and carrier dynamics of individual NPLs using second-order photon correlation (g(2)(Ï.,)) spectroscopy and photoluminescence (PL) intensity-dependent lifetime analysis. Room-temperature radiative lifetimes of NPLs can be derived from maximum PL intensity periods in PL time traces. It first decreases with NPL lateral size and then stays constant, deviating from the electric dipole approximation. Analysis of the PL time traces further reveals that the single exciton quantum yield in NPLs decreases with NPL lateral size and increases with protecting shell thickness, indicating the importance of surface passivation on NPL emission quality. Second-order photon correlation (g(2)(Ï.,)) studies of single NPLs show that the biexciton quantum yield is strongly dependent on the lateral size and single exciton quantum yield of the NPLs. In large NPLs with unity single exciton quantum yield, the corresponding biexciton quantum yield can reach unity. These findings reveal that by careful growth control and core-shell material engineering, NPLs can be of great potential for light amplification and integrated quantum photonic applications.

Original languageEnglish
Pages (from-to)9119-9127
Number of pages9
JournalACS nano
Issue number9
Publication statusPublished - Sep 26 2017


  • CdSe/CdS nanoplatelets
  • biexciton
  • exciton coherent motion area
  • quasi-2D exciton
  • radiative lifetime
  • second-order photon correlation function

ASJC Scopus subject areas

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

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