Dynamic Trap Formation and Elimination in Colloidal Quantum Dots

Type
Article

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

KAUST Grant Number
KUS-11-009-21

Online Publication Date
2013-03-11

Print Publication Date
2013-03-21

Date
2013-03-11

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.

Citation
Voznyy O, Thon SM, Ip AH, Sargent EH (2013) Dynamic Trap Formation and Elimination in Colloidal Quantum Dots. The Journal of Physical Chemistry Letters 4: 987–992. Available: http://dx.doi.org/10.1021/jz400125r.

Acknowledgements
This publication is based in part on work supported by Award KUS-11-009-21, made by King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program, and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. Computations were performed on the GPC supercomputer at the SciNet HPC Consortium.44 SciNet is funded by the Canada Foundation for Innovation under the auspices of Compute Canada, the Government of Ontario, the Ontario Research Fund - Research Excellence, and the University of Toronto.

Publisher
American Chemical Society (ACS)

Journal
The Journal of Physical Chemistry Letters

DOI
10.1021/jz400125r

PubMed ID
26291365

Permanent link to this record