Dynamic Trap Formation and Elimination in Colloidal Quantum Dots

O. Voznyy, S. M. Thon, A. H. Ip, E. H. Sargent

Research output: Contribution to journalArticlepeer-review

90 Scopus citations

Abstract

Using first-principles simulations on PbS and CdSe colloidal quantum dots, we find that surface defects form in response to electronic doping and charging of the nanoparticles. We show that electronic trap states in nanocrystals are dynamic entities, in contrast with the conventional picture wherein traps are viewed as stable electronic states that can be filled or emptied, but not created or destroyed. These traps arise from the formation or breaking of atomic dimers at the nanoparticle surface. The dimers' energy levels can reside within the bandgap, in which case a trap is formed. Fortunately, we are also able to identify a number of shallow-electron-affinity cations that stabilize the surface, working to counter dynamic trap formation and allowing for trap-free doping. © 2013 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)987-992
Number of pages6
JournalThe Journal of Physical Chemistry Letters
Volume4
Issue number6
DOIs
StatePublished - Mar 11 2013
Externally publishedYes

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