Electronics from Nano-Cell Crystals

Abstract

This report documents the progress during the past year of a project to uncover the fundamental charge transport mechanisms in organic materials, concentration on crystalline systems and in device configurations. The project has produced solid results in molecular synthesis, crystal growth, electrical and optical characterization. The team has reached out and is collaborating with external groups, and therefore leverages well the DOE funds. Of particular note is the discovery of a method to systematically dope rubrene in a field-effect-transistor device configuration. Previous work in conducting polymers demonstrated orders of magnitude enhancement of conductivity, but in conjunction with changing mobility. For active devices (such as FETs) operation, the mobility must be independent of carrier concentration. We have shown for the first time in an organic system, that the carrier concentration can be changed independently of the FET mobility. Thus we have achieved a similar level of carrier concentration control as is routinely found in inorganic semiconductors. This result will enable the field of organics to proceed faster towards high performance devices for logic and photovoltaic functionality.