Efficient color-tunable multiexcitonic dual wavelength emission from type II semiconductor tetrapods

Wen Ya Wu, Mingjie Li, Jie Lian, Xiangyang Wu, Edwin K.L. Yeow, Mark H. Jhon, Yinthai Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

15 Citations (Scopus)

Abstract

We synthesized colloidal InP/ZnS seeded CdS tetrapods by harnessing the structural stability of the InP/ZnS seed nanocrystals at the high reaction temperatures needed to grow the CdS arms. Because of an unexpected Type II band alignment at the interface of the InP/ZnS core and CdS arms that enhanced the occurrence of radiative excitonic recombination in CdS, these tetrapods were found to be capable of exhibiting highly efficient multiexcitonic dual wavelength emission of equal intensity at spectrally distinct wavelengths of ∼485 and ∼675 nm. Additionally, the Type II InP/ZnS seeded CdS tetrapods displayed a wider range of pump-dependent emission color-tunability (from red to white to blue) within the context of a CIE 1931 chromaticity diagram and possessed higher photostability due to suppressed multiexcitonic Auger recombination when compared to conventional Type I CdSe seeded CdS tetrapods. By employing time-resolved spectroscopy measurements, we were able to attribute the wide emission color-tunability to the large valence band offset between InP and CdS. This work highlights the importance of band alignment in the synthetic design of semiconductor nanoheterostructures, which can exhibit color-tunable multiwavelength emission with high efficiency and photostability.

Original languageEnglish
Pages (from-to)9349-9357
Number of pages9
JournalACS Nano
Volume8
Issue number9
DOIs
Publication statusPublished - 23 Sep 2014
Externally publishedYes

Keywords

  • color-tunable
  • dual-emission
  • InP/CdS
  • multiexciton
  • tetrapod
  • Type II

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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