Conjugated polymer/layered inorganic nanocomposites: solution processable route to enhanced thermoelectric performance

In recent years, incorporation of nanostructuring has led to notable improvements in the performance of thermoelectric materials. At a given temperature T, the thermoelectric figure of merit ZT is given by $\frac{S^2\sigma T}{\kappa }$ , where S is the Seebeck coefficient, $\sigma $ the electrical conductivity and $\kappa $ the thermal conductivity. In most cases, improvement in ZT through nanostructuring has been realized via reduction in thermal conductivity $\kappa $ rather than increases in the power factor S$^{2}\sigma $. Here we utilize solution-based intercalation chemistry to create layered inorganic/conjugated polymer nanocomposites with designed nanoscale interfaces engineered to enhance the power factor by energy filtering. The layered inorganic material Sb$_{2}$Te$_{3}$ was intercalated with poly(3-hexylthiophene), and the resulting composite material was cast into thin films from solution. The resulting devices exhibit Seebeck coefficients with two-fold enhancement over those reported for bulk Sb$_{2}$Te$_{3 }$with known conductivities for solution-processed films. These results demonstrate the promise of these novel intercalated materials for high performance solution processable thermoelectric materials.