Near-Unity Quantum Yields of Biexciton Emission from CdSe/CdS Nanocrystals Measured Using Single-Particle Spectroscopy

作者:Park Y S; Malko A V; Vela J; Chen Y; Ghosh Y; Garcia Santamaria F; Hollingsworth J A; Klimov V I*; Htoon H
来源:Physical Review Letters, 2011, 106(18): 187401.
DOI:10.1103/PhysRevLett.106.187401

摘要

Biexciton photoluminescence (PL) quantum yields (Q(2X)) of individual CdSe/CdS core-shell nanocrystal quantum dots with various shell thicknesses are derived from independent PL saturation and two-photon correlation measurements. We observe a near-unity Q(2X) for some nanocrystals with an ultrathick 19-monolayer shell. High Q(2X)'s are, however, not universal and vary widely among nominally identical nanocrystals indicating a significant dependence of Q(2X) upon subtle structural differences. Interestingly, our measurements indicate that high Q(2X)'s are not required to achieve complete suppression of PL intensity fluctuations in individual nanocrystals.

  • 出版日期2011-5-3