State-of-the-art research in conducting polymer thermoelectric composites: Design strategies, doping innovations, and emerging technologies

Conducting polymer-based thermoelectric composites have emerged as a promising candidate for flexible, lightweight, and cost-effective energy conversion systems, addressing the ever growing demand for sustainable energy solutions. Researchers have concentrated on optimizing thermoelectric properties by incorporating nanostructures, hybrid fillers, and doping methods, which enhance electrical conductivity alongside Seebeck coefficients while minimizing thermal conductivity. Further, novel processing techniques, including solution casting, melt blending, and surface functionalization, are employed to ensure uniform filler dispersion and enhance the mechanical flexibility of polymer-based composites, thereby paving their way in flexible and wearable thermoelectric devices. This review covers various aspects, such as different models describing charge transport, diverse array of nano-fillers, and the factors affecting thermoelectric properties of polymer nanocomposites, synthetic schemes, doping, and post-treatment strategies to maximize the power factor along with recent breakthroughs in diverse applications, namely, electrical, optoelectronics, electronics, sensing, and biomedical. Various research gaps, potential issues along with possible solutions, and future prospects have been elaborated at length and would assist the researchers for a better understanding and research direction.