(116ae) Microwave Synthesis of Cadmium Selenide Quantum Dots

Fluorescent quantum dots (QD) are collections of semiconductor atoms on the order of a few nanometers. Their emission properties are dictated by the surface state and traps of the nanoparticles, and the size of the particle. Quantum dots are an emerging alternative to traditional dyes for solar cells and bio-imaging because of their high quantum efficiency, stable emission, and ability to control their solubility and biological affinity through changing the chemistry of the QD ligands. One of the drawbacks of QDs is the need for oxygen and water free synthesis conditions, and difficulty producing high quantum efficiency water soluble particles. We present a general method of synthesizing water soluble core-shell QDs. The water soluble core-shell QDs are synthesized by microwave heating from commercially available precursors in the presence of water and oxygen in minutes. The microwave synthesis of QDs is sensitive to the choice of non-solvent, ligand and reaction temperature. Kinetic experiments were performed to determine the optimal conditions to achieve QDs with fluorescent emission from wavelengths of 450 nm to 700 nm. Use of the microwave to synthesize QDs allows for the controlled synthesis of an array of different QD's, and the ability to tailor the chemical functionality of the QD surface with ligands.