Photo-Seebeck Effects in Doped P3HT Composites

As the global energy and environmental preservation needs continue to grow, the demand for renewable and clean energy conversion materials and devices continues to rise as well. Thermoelectric (TE) materials and devices can convert waste heat into electricity and therefore it can be a potential renewable and clean energy source. Organic and polymeric materials typically exhibit low electrical conductivities, high Seebeck coefficients, and orders of magnitude lower thermal conductivities as compared to their inorganic counterparts. However, the electrical conductivities of organic/polymeric materials are tunable via doping or molecular engineering. In this study, a series of carefully doped P3HT composites are systematically evaluated for heat as well as light modulated devices. Along with a high absorption coefficient, when the polymer film thickness is less than the penetration depth of the incoming photons, the photo effects are significant and could be very useful for light modulations of thermoelectric functions. With further systematic studies and a better understanding of the mechanisms behind the photo-Seebeck effect, the development of potential high-efficiency multi-function materials and devices appears feasible.