Advances in carbon-based thermoelectric materials for high-performance, flexible thermoelectric devices

Waste energy harvesting can contribute to the increase of the efficiency of many industrial processes, which consume energy to produce valuable products. Among all the wasted energy, heat energy is the most abundant, existing in almost any situation. Thermoelectric devices have the capability to harvest and convert the thermal energy into electrical power via the Seebeck effect. With its simple operating principle, thermoelectric devices can be reliable even under the harshest environments, taking advantage of any type of heat source. As a result, various inorganic and organic materials are being explored as thermoelectric materials. Among the reported materials, carbon-based materials are promising in terms of commericialization, due to their nontoxic and abundant nature, and solution processability. In particular, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), carbon nanotubes, and graphene are extensively studied as thermoelectric materials owing to their remarkable thermoelectric performance. Also, organic–inorganic hybrid halide perovskites show the potential to be used as future high-performance thermoelectric materials. Here, the progess in carbon materials as thermoelectrics is reviewed in detail, focusing on four base materials (PEDOT:PSS, carbon nanotubes, graphene, and organic–inorganic hybrid halide perovskites). This review illuminates the potential of carbon-based materials in the field of thermoelectrics and their application to next-generation energy devices.