Field dependent thermoelectric properties of organic semiconductors—A tool to determine the nature of charge transport in materials exhibiting thermally activated transport

Abstract

By implementing Monte Carlo simulations and employing the concept of effective temperature, we explore the effects of an applied field bias on the charge carrier statistics and Peltier coefficient in hopping systems subject to the parameter range applicable to disordered organic semiconductors. Distinct differences are found between the observed field dependences as obtained from systems in which energetic disorder is spatially correlated and those in which it is not. Considerable differences are also found between the charge carrier statistics and the Peltier coefficient's field dependence in systems in which charge is transported by bare charge carriers and systems in which it is propagated by polarons. Peltier coefficient field dependence investigations are, hence, proposed as a new tool for studying charge transport and thermoelectricity in disordered organic semiconductors and systems which exhibit thermally activated transport in general.