Enhanced Thermoelectric Properties in Tailored Semiconducting SWCNT Networks

Single-walled carbon nanotubes (SWCNTs) are a versatile electronic material being explored as cost-effective, high-performance alternative in a variety of renewable energy applications. In this talk, we present a series of experiments designed to probe the thermal and electrical transport through networks of semiconducting SWCNT dispersed in matrices of polyfluorene polymers. We measured electrical transport as a function of hole density to explore the coupling between the electrical conductivity and Seebeck coefficient (thermopower) in the s-SWCNT networks. These networks exhibit large thermopowers $> 1000$ $\mu $V/K at very low hole densities. Thermopower values remain high at high doping levels, resulting in thermoelectric power factors greater than 340 $\mu $W/m K. Finally, we present measurements that demonstrate our doping process significantly reduces the thermal conductivity relative to undoped networks suggesting s-SWCNTs are a viable material for realizing thermally stable room temperature thermoelectric devices fashioned from inexpensive and abundant organic constituents.