Band structure engineering via piezoelectric fields in strained anisotropic CdSe/CdS nanocrystals

Sotirios Christodoulou, Fernando Rajadell, Alberto Casu, Gianfranco Vaccaro, Joel Q. Grim, Alessandro Genovese, Liberato Manna, Juan I. Climente, Francesco Meinardi, Gabriele Rainò, Thilo Stöferle, Rainer F. Mahrt, Josep Planelles, Sergio Brovelli, Iwan Moreels*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

Strain in colloidal heteronanocrystals with non-centrosymmetric lattices presents a unique opportunity for controlling optoelectronic properties and adds a new degree of freedom to existing wavefunction engineering and doping paradigms. We synthesized wurtzite CdSe nanorods embedded in a thick CdS shell, hereby exploiting the large lattice mismatch between the two domains to generate a compressive strain of the CdSe core and a strong piezoelectric potential along its c-axis. Efficient charge separation results in an indirect ground-state transition with a lifetime of several microseconds, almost one order of magnitude longer than any other CdSe/CdS nanocrystal. Higher excited states recombine radiatively in the nanosecond time range, due to increasingly overlapping excited-state orbitals. k? p calculations confirm the importance of the anisotropic shape and crystal structure in the buildup of the piezoelectric potential. Strain engineering thus presents an efficient approach to highly tunable single- and multiexciton interactions, driven by a dedicated core/shell nanocrystal design.

Original languageEnglish (US)
Article number7905
JournalNature Communications
Volume6
DOIs
StatePublished - Jul 29 2015

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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