Electronic transport and thermoelectric power generation in nanocrystal assemblies

Lead telluride(PbTe) nanoparticles are a material of high interest due to the strong confinement on electrons and phonons. "Artificial solids" composed of these "artificial atoms" as a building block opens a new opportunity in tuning various physical properties. Furthermore, construction of compound solids with silver telluride(Ag2Te) nanoparticles, as p-type dopants, enable us to study new collective properties of nanoparticle assemblies in electronic devices as well as thermoelectric modules. This presentation reports the synthesis and characterization of monodisperse lead telluride and silver telluride nanoparticles. Size of lead telluride nanoparticles were controlled by additional injection of precursors, where the distribution of nanoparticle size refocuses as the nanoparticles further grow in diffusion-controlled growth regime. Highly monodisperse silver telluride nanoparticles were obtained by digestive ripening process, showing a great advatange in large scale synthesis. Charge transport through nanoparticle assemblies was investigated by solution processed field effect transistor as a function of interparticle spacing and temperature of heat treatment. The feasibility as a thermoelectric energy conversion for waste heat recovery application is also proposed.