Resilient Pathways to Atomic Attachment of Quantum Dot Dimers and Artificial Solids from Faceted CdSe Quantum Dot Building Blocks

Justin C. Ondry, John P. Philbin, Michael Lostica, Eran Rabani, A. Paul Alivisatos

Research output: Contribution to journalArticlepeer-review


The goal of this work is to identify favored pathways for preparation of defect-resilient attached wurtzite CdX (X = S, Se, Te) nanocrystals. We seek guidelines for oriented attachment of faceted nanocrystals that are most likely to yield pairs of nanocrystals with either few or no electronic defects or electronic defects that are in and of themselves desirable and stable. Using a combination of in situ high-resolution transmission electron microscopy (HRTEM) and electronic structure calculations, we evaluate the relative merits of atomic attachment of wurtzite CdSe nanocrystals on the {11̄ 00} or {112̄ 0} family of facets. Pairwise attachment on either facet can lead to perfect interfaces, provided the nanocrystal facets are perfectly flat and the angles between the nanocrystals can adjust during the assembly. Considering defective attachment, we observe for {11̄ 00} facet attachment that only one type of edge dislocation forms, creating deep hole traps. For {112̄ 0} facet attachment, we observe that four distinct types of extended defects form, some of which lead to deep hole traps whereas others only to shallow hole traps. HRTEM movies of the dislocation dynamics show that dislocations at {11̄ 00} interfaces can be removed, albeit slowly. Whereas only some extended defects at {112̄ 0} interfaces could be removed, others were trapped at the interface. Based on these insights, we identify the most resilient pathways to atomic attachment of pairs of wurtzite CdX nanocrystals and consider how these insights can translate to the creation of electronically useful materials from quantum dots with other crystal structures.

Original languageEnglish
Pages (from-to)12322-12344
Number of pages23
JournalACS Nano
Issue number11
StatePublished - 26 Nov 2019


  • CdSe
  • dislocations
  • electronic structure
  • in situ TEM
  • nanocrystals
  • oriented attachment


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