Effects of surface passivation on the exciton dynamics of CdSe nanocrystals as observed by ultrafast fluorescence upconversion spectroscopy.
The exciton dynamics of CdSe nanocrystals are intimately linked to the surface morphology. Photo-oxidation of the selenium surfaces of the nanocrystal leads to an increase in radiative decay efficiency from both the band edge and deep trap emission states. The addition of the primary amine hexadecylamine curtails nonradiative excitonic decay attributed to the dangling surface selenium orbitals by passivation of those trap sites by the methylene protons on the amine, leading to enhanced band edge emission and the absence of deep trap emission. Furthermore, CdSeZnSe core/shell nanocrystals are not immune from contributions from surface states because of the alignment of the band structures of the core and shell materials.
Kippeny
Tadd C
TC
Department of Chemistry, Vanderbilt University, VU Station B, Box 351822, Nashville, Tennessee 37235, USA.
Bowers
Michael J
MJ
Dukes
Albert D
AD
McBride
James R
JR
Orndorff
Rebecca L
RL
Garrett
Maria Danielle
MD
Rosenthal
Sandra J
SJ