Germanium nanoparticles for solar energy conversion

Photovoltaic cells made from all-inorganic nanocrystals offer advantages in terms of stability over polymer-based solar cells. Multiple Exciton Generation (MEG) pathway is currently explored in quantum confined semiconducting nanoparticles to increase the efficiency of solar cells. Colloidal preparations of semiconducting nanoparticles are the preferred method for device fabrication. However, the colloidal synthesis of Si and Ge are not well established as the metal chalcogenide systems. Reported methods in literature for Ge nanoparticles do not offer much control on size and morphology. In addition many of these methods provide low yields. In this work, germanium nanoparticles have been synthesized by the reaction of germanium iodide with hexamethyldisilazane in a mixture of oleylamine and oleic acid under Ar at ≥300°C. Reaction conditions have been optimized to prepare monodisperse nanoparticles in high yields. Ge nanoparticles of different sizes will be prepared and the size effect will eventually be tested on the photovoltaic properties.