Approximately 65% of primary energy globally is lost to the environment as waste heat. Solutions for conversion of this energy into useful work depend upon the temperature at which the heat is generated. Thermoelectrics provides an attractive alternative to harvest this waste heat. Furthermore, thermoelectrics are being integrated into heat scavenging strategies for wearable electronics and for distributed sensors, where naturally occurring temperature gradients can power devices. Thermoelectrics can also be operated in reverse where electricity can be used to provide cooling. For this application, thermoelectrics are now found commercially in portable refrigerators, dehumidifiers, and even in cloth dryers. Emerging wearable technologies using thermoelectrics are now providing personal cooling. Innovation in materials as well as novel concepts in condensed matter physics have assisted in this development. In addition, broader engineering approaches such as thermo-electro-chemical converters are starting to emerge as alternative strategies that have the potential to outperform conventional thermoelectrics in some applications. Thermo-electro-chemical convertors, similar to thermoelectrics, are attractive because they can leverage advances in the high roundtrip efficiencies of electrochemical systems, such as batteries, to provide efficient power generation and cooling.

Such emerging technologies are the need of the hour. However, there are a number of open scientific and engineering questions that remain to be addressed in these conversion strategies and their constituent materials. Much is still desired in order to perform thermal-to-electric conversion efficiently. To this end, in this symposium we will focus on new classes of organic-based thermoelectric materials as well as novel designs for organic thermoelectric energy conversion devices. These include new synthetic routes for conjugated polymers and dopants, metal-coordinated polymers, and hybrid organic-inorganic thermoelectric materials that may or may not mimic the physics of degenerate band-like semiconductors. Furthermore, the effect of energy alignment and morphology on the electrical and thermal properties of many of these materials is being actively studied and is a topic of interest. For thermo-electro-chemical conversion, the appropriate cathodlyte and anodlyte chemistries are still being explored and the fundamental transport mechanisms require additional study. Appropriate electrode materials, electrolytes, and half-reaction chemistries are still an active area of research. In both cases (thermoelectrics and thermo-electro-chemical conversion), new device geometries are enabled by the manufacturing and processing of these materials that cannot be realized with conventional thermoelectric materials and concepts.

electrical properties electronic structure energy generation morphology organometallic polymer thermal conductivity thermionic emission thermoelectric thermoelectricity