Auger-Limited Carrier Recombination and Relaxation in CdSe Colloidal Quantum Wells

Baghani, Erfan, Stephen K. O’Leary, Igor Fedin, Dmitri V. Talapin, and Matthew Pelton. “Auger-Limited Carrier Recombination and Relaxation in CdSe Colloidal Quantum Wells.” The Journal of Physical Chemistry Letters 6, no. 6 (March 19, 2015): 1032–36. https://doi.org/10.1021/acs.jpclett.5b00143.

Rights

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/acs.jpclett.5b00143.

Abstract

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.