Strategies To Enhance the Conductivity of n-Type Polymer Thermoelectric Materials

In the past several decades, conducting polymers have achieved remarkable progress and have been widely applied as the active materials for optoelectronics. So far, p-type conducting polymers exhibit high conductivities over 1000 S cm–1 and thermoelectric performance comparable to that of inorganic materials; however, only a few n-type conducting polymers showed conductivities over 1 S cm–1 after doping. The low conductivity of n-type conducting polymers is considered as the major barrier for further enhancing their thermoelectric performances. In this perspective, we highlight the scientific and engineering challenges to enhance the conductivity of n-type polymer thermoelectric materials, including n-doping efficiency in n-type polymers, factors influencing charge carrier mobilities after doping, and stability of n-type conducting polymers. Recent development and strategies to address these issues and enhance the conductivity of n-type conjugated polymers are summarized and discussed, providing materials and device engineering guidelines for the future high-performance polymer thermoelectric materials research and development.