Unraveling the Origin of Interfacial Oxidation of InP-Based Quantum Dots: Implications for Bioimaging and Optoelectronics

Ajit Vikram, Arwa Zahid, Saket S. Bhargava, Hyukjin Jang, Andre Sutrisno, Ankur Khare, Peter Trefonas, Moonsub Shim, Paul J.A. Kenis

Research output: Contribution to journalArticlepeer-review

Abstract

Indium phosphide core/shell nanocrystals hold promise to replace heavy-metal-based emissive materials for bioimaging and optoelectronic applications. Uniformity of the shell passivation and the interfacial defects are critical for achieving improved optical properties. A combination of Fourier-transform infrared spectroscopy (FTIR) and liquid and solid-state NMR spectroscopy revealed a strong correlation between interfacial oxidation and photoluminescence of InP-based core/shell quantum dots. Using an automated sequential shell growth approach enabled efficient flow synthesis of InP/ZnSe/ZnS quantum dots, exhibiting high-quantum yields and narrow emission line widths. Feeding individual precursors into the reactor channel in a sequential fashion combined with inline reaction monitoring enabled precise control over layer-by-layer shell passivation of the core particles. Our findings suggest that an unintentional aminolytic reaction between oleylamine and carboxylates (two most commonly used starting materials for colloidal synthesis) introduces oxidative defects during the shelling process, thus limiting their optical properties.

Original languageEnglish (US)
Pages (from-to)12325-12333
Number of pages9
JournalACS Applied Nano Materials
Volume3
Issue number12
DOIs
StatePublished - Dec 24 2020

Keywords

  • core/shell nanocrystals
  • flow synthesis
  • indium phosphide
  • interfacial oxidation
  • quantum dots

ASJC Scopus subject areas

  • Materials Science(all)

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