Quantum Dots: An Experiment for Physical or Materials Chemistry

An experiment involving the synthesis and optical characterization of nanoparticles of the semiconductor CdS is described. The synthesis uses inexpensive chemicals, a simple setup, and can be completed in less than one hour. The synthesis is also considerably less hazardous than other protocols as solvents, reaction conditions, and reagents are all suitable for undergraduate use. The optical characterization is by absorption and emission spectroscopy. Simple theory allows the calculation of the effects of quantum confinement to be correlated with the observed spectra. The experiment provides a bridge between the molecular and the solid state worlds.