Thermoelectric power generation from the perspective of conducting polymers

The field of thermoelectric power generation is now looking towards conducting polymers (CPs) as novel materials for harnessing low-temperature (≤ 150°C) waste heat into useful electrical power. For instance, PEDOT:PSS due to its high electrical conductivity and water soluble nature has emerged as a promising substitute of expensive, toxic and rigid inorganic counterparts for room temperature thermoelectrics. Therefore, the present work has been focussed on improvement of its thermoelectric performance through use of organic solvent ethylene glycol (EG). It was observed that drop-casted films (on polyimide substrates) prepared using EG mixed PEDOT:PSS resulted in enhancement of electrical conductivity (from ~1.6 Sicm of pristine to ~123.3 Sicm for EG-mixed) without much affecting the Seebeck coefficient (~8-14 µViK). The films were also optimized for solvent concentrations. This enhancement of thermoelectric performance has been attributed to selective removal of insulating PSS which resulted in enhanced ordering of PEDOT:PSS chains. The investigation made in this work suggests that CPs based films can be easily modified to improve their thermoelectric performance for practical applications.