Size-confined fixed-composition and composition-dependent engineered band gap alloying induces different internal structures in L-cysteine-capped alloyed quaternary CdZnTeS quantum dots

Oluwasesan Adegoke, Enoch Y. Park (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)
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Abstract

The development of alloyed quantum dot (QD) nanocrystals with attractive optical properties for a wide array of chemical and biological applications is a growing research field. In this work, size-tunable engineered band gap composition-dependent alloying and fixed-composition alloying were employed to fabricate new L-cysteine-capped alloyed quaternary CdZnTeS QDs exhibiting different internal structures. Lattice parameters simulated based on powder X-ray diffraction (PXRD) revealed the internal structure of the composition-dependent alloyed CdxZnyTeS QDs to have a gradient nature, whereas the fixed-composition alloyed QDs exhibited a homogenous internal structure. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis confirmed the size-confined nature and monodispersity of the alloyed nanocrystals. The zeta potential values were within the accepted range of colloidal stability. Circular dichroism (CD) analysis showed that the surface-capped L-cysteine ligand induced electronic and conformational chiroptical changes in the alloyed nanocrystals. The photoluminescence (PL) quantum yield (QY) values of the gradient alloyed QDs were 27-61%, whereas for the homogenous alloyed QDs, the PL QY values were spectacularly high (72-93%). Our work demonstrates that engineered fixed alloying produces homogenous QD nanocrystals with higher PL QY than composition-dependent alloying.

Original languageEnglish
Article number27288
Pages (from-to)1-9
Number of pages9
JournalScientific Reports
Volume6
DOIs
Publication statusPublished - 2 Jun 2016

Keywords

  • Alloys/chemistry
  • Cadmium/chemistry
  • Circular Dichroism
  • Cysteine/chemistry
  • Dynamic Light Scattering
  • Microscopy, Electron, Transmission
  • Molecular Structure
  • Nanoparticles/chemistry
  • Particle Size
  • Quantum Dots/chemistry
  • Tellurium/chemistry
  • Zinc/chemistry

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