Auger-Limited Carrier Recombination and Relaxation in CdSe Colloidal Quantum Wells.
Using time-resolved photoluminescence spectroscopy, we show that two-exciton Auger recombination dominates carrier recombination and cooling dynamics in CdSe nanoplatelets, or colloidal quantum wells. The electron-hole recombination rate depends only on the number of electron-hole pairs present in each nanoplatelet, and is consistent with a two-exciton recombination process over a wide range of exciton densities. The carrier relaxation rate within the conduction and valence bands also depends only on the number of electron-hole pairs present, apart from an initial rapid decay, and is consistent with the cooling rate being limited by reheating due to Auger recombination processes. These Auger-limited recombination and relaxation dynamics are qualitatively different from the carrier dynamics in either colloidal quantum dots or epitaxial quantum wells.
†School of Engineering, The University of British Columbia, Kelowna, British Columbia V1V 1V7, Canada.
Erfan
E
Baghani
†School of Engineering, The University of British Columbia, Kelowna, British Columbia V1V 1V7, Canada.
Stephen K
SK
O'Leary
‡Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States.
Igor
I
Fedin
‡Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States.|§Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States.
Dmitri V
DV
Talapin
§Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States.|∥Department of Physics, University of Maryland-Baltimore County, Baltimore, Maryland 21250, United States.
Matthew
M
Pelton
Auger Recombination; Biexciton; Cadmium Selenide; Carrier Cooling; Colloidal; Nanoplatelet