ZnSe/ZnS Core/Shell Quantum Dots with Superior Optical Properties through Thermodynamic Shell Growth

Botao Ji, Somnath Koley, Ilya Slobodkin, Sergei Remennik, Uri Banin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

83 Scopus citations

Abstract

Epitaxial growth of a protective semiconductor shell on a colloidal quantum dot (QD) core is the key strategy for achieving high fluorescence quantum efficiency and essential stability for optoelectronic applications and biotagging with emissive QDs. Herein we investigate the effect of shell growth rate on the structure and optical properties in blue-emitting ZnSe/ ZnS QDs with narrow emission line width. Tuning the precursor reactivity modifies the growth mode of ZnS shells on ZnSe cores transforming from kinetic (fast) to thermodynamic (slow) growth regimes. In the thermodynamic growth regime, enhanced fluorescence quantum yields and reduced on−off blinking are achieved. This high performance is ascribed to the effective avoidance of traps at the interface between the core and the shell, which are detrimental to the emission properties. Our study points to a general strategy to obtain high-quality core/shell QDs with enhanced optical properties through controlled reactivity yielding shell growth in the thermodynamic limit.

Original languageAmerican English
Pages (from-to)2387-2395
Number of pages9
JournalNano Letters
Volume20
Issue number4
DOIs
StatePublished - 2020

Bibliographical note

Funding Information:
We thank Dr. Jiabin Cui from The Institute of Chemistry at the Hebrew University for the assistance in the materials characterization. The research has received funding from the Israel Science Foundation (ISF, Grant 1363/18) in the frame of the Alternative Fuels Program. S.K. acknowledges the support from the Planning and Budgeting Committee of the higher board of education in Israel through a fellowship. U.B. thanks the Alfred & Erica Larisch memorial chair.

Publisher Copyright:
Copyright © 2020 American Chemical Society.

Keywords

  • ZnSe/ZnS
  • core/shell QDs
  • heavy-metal-free
  • kinetic
  • thermodynamic

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