Date of Award
Spring 1-1-2013
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Chemistry & Biochemistry
First Advisor
Arthur J. Nozik
Second Advisor
Gordana Dukovic
Third Advisor
Niels H. Damrauer
Abstract
We have measured the temperature-dependent photoluminescence (PL) and quantum yield (QY) of a series of alkanedithiol-treated PbS quantum dot (QD) films as a function of QD size and the length of the alkane chain. These films have PLQYs ranging 2% - 40% at 20 K, with the lowest values measured for shorter ligands and larger QD sizes. All films show PL quenching and shifting/narrowing with increased temperature characterized by exponential (Urbach) band tail behavior. The PLQY vs temperature takes a form derived from an Arrhenius-like dependence of activated charge separation. We also find temperature-dependent photoconductivity (σ), showing an Arrhenius relationship with inverse temperature (T-0.5 at lower temperature matching variable-range hopping model and T-1 at higher temperature corresponding to near-neighbor hopping model), is inversely related with temperature-dependent PL. This indicates that temperature-dependent PL is a relevant measure of transport properties in the presence of deep trap states and reasonably high charge carrier mobilities.
Recommended Citation
Zhang, Jing, "The Mechanism of Thermally-Activated Photoluminescence Quenching and Its Correlation with Transport in Electronically-Coupled PbS Quantum Dot Arrays" (2013). Chemistry & Biochemistry Graduate Theses & Dissertations. 145.
https://scholar.colorado.edu/chem_gradetds/145