Suppressed blinking and auger recombination in near-infrared type-II InP/CdS nanocrystal quantum dots

Allison M. Dennis, Benjamin D. Mangum, Andrei Piryatinski, Young Shin Park, Daniel C. Hannah, Joanna L. Casson, Darrick J. Williams, Richard D. Schaller, Han Htoon, Jennifer A. Hollingsworth

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Abstract

Nonblinking excitonic emission from near-infrared and type-II nanocrystal quantum dots (NQDs) is reported for the first time. To realize this unusual degree of stability at the single-dot level, novel InP/CdS core/shell NQDs were synthesized for a range of shell thicknesses (∼1-11 monolayers of CdS). Ensemble spectroscopy measurements (photoluminescence peak position and radiative lifetimes) and electronic structure calculations established the transition from type-I to type-II band alignment in these heterostructured NQDs. More significantly, single-NQD studies revealed clear evidence for blinking suppression that was not strongly shell-thickness dependent, while photobleaching and biexciton lifetimes trended explicitly with extent of shelling. Specifically, very long biexciton lifetimes-up to >7 ns-were obtained for the thickest-shell structures, indicating dramatic suppression of nonradiative Auger recombination. This new system demonstrates that electronic structure and shell thickness can be employed together to effect control over key single-dot and ensemble NQD photophysical properties.

Original languageEnglish
Pages (from-to)5545-5551
Number of pages7
JournalNano letters
Volume12
Issue number11
DOIs
Publication statusPublished - Nov 14 2012

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Keywords

  • Auger recombination
  • Fluorescence blinking suppression
  • biexciton lifetime
  • core/shell heterostructure
  • near-infrared
  • type-II nanocrystal quantum dot

ASJC Scopus subject areas

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

Cite this

Dennis, A. M., Mangum, B. D., Piryatinski, A., Park, Y. S., Hannah, D. C., Casson, J. L., Williams, D. J., Schaller, R. D., Htoon, H., & Hollingsworth, J. A. (2012). Suppressed blinking and auger recombination in near-infrared type-II InP/CdS nanocrystal quantum dots. Nano letters, 12(11), 5545-5551. https://doi.org/10.1021/nl302453x