Universality of the giant Seebeck effect in organic small molecules

To explore the universality of the giant Seebeck coefficient (>100 mV K−1) found in our previous study with pure C60 thin films, the thermoelectric properties of high-mobility small-molecule organic semiconductors and their temperature dependencies are investigated. Consequently, various pure organic semiconductors exhibited similar large Seebeck coefficients within the temperature range of 300–360 K. The magnitude of the Seebeck coefficient, its intense temperature dependence, and correlation with the activation energy of electrical conductivity are unique and cannot be elucidated by currently known physical models of thermoelectricity.