Synthesis of Lead Sulfide Quantum Dots and their Ligands for Photon Upconversion Applications

Lead sulfide quantum dots (PbS QDs) are prime candidates for various optical applications due to their size-dependent optical properties, tunability, narrow absorption peaks, and their spin-mixing properties. Small PbS QDs have proven to be a synthetic challenge but are important candidates for use in optical upconversion which is the process by which low energy photons are combined to form a higher energy photon. We describe our attempts at optimizing the relatively new synthetic method of using thioureas as precursors to make small PbS QDs, as well as determining the mechanism of monomer formation. We also describe our synthesis and characterization of 5-(p-carboxyphenyl)tetracene, a ligand that can act as a triplet extractor from PbS QDs for use in optical upconversion.M.Sc