제목: Doped semiconducting polymers for organic electronic devices

내용: Organic thermoelectric (TE) materials have gained increasing attention owing to their ability to effectively convert waste heat into electrical energy at low temperatures, rational design of molecular structures to achieve desired TE properties, solution processability on a flexible substrate at room temperature, and extension of the TE boundaries that inorganic materials alone cannot address. To optimize the performance of organic TE generators, high electrical conductivity (σ) is the most important prerequisite. As σ is determined by the carrier concentration and mobility (σ = neμ; n is the carrier concentration; e is the electron charge; μ is the carrier mobility), the doping characteristics need to be well controlled to increase the doping level to obtain high conductivity. Despite extensive studies on various TE materials, only a few structures have successfully achieved a high σ of over ~1000 S cm^-1. In this presentation, the electrical and TE characteristics of a series of p-type conjugated polymers by molecular doping will be discussed. Furthermore, the selective doping of the semiconducting polymer layer enables the successful formation of a homojunction between the semiconductor and the electrode as an alternative to existing heterojunction-based devices; this homojunction consequently improves the mechanical stability of the polymer thin film transistors. The detailed doping properties and resulting device characteristics will be presented.