Conducting Polymers: Materials, Mechanisms, and Applications – a Review

The 2000 Nobel Prize in Chemistry was awarded to Alan J. Heeger, Alan G. MacDiarmid, and Hideki Shirakawa for the discovery and development of conductive polymers, particularly polyacetylene. Since then, research on conducting polymers has progressed rapidly, with sustained focus on their morphology, structural design, and technological applications. This paper presents a comprehensive review of conducting polymers, focusing on their structure, synthesis, and applications in electrical, optical, and energy-conversion technologies. Prominent systems – including polyaniline, polypyrrole, polythiophene, polyacetylene, poly(p-phenylene vinylene) (PPV), poly(p-phenylene) (PPP), and poly(3,4-ethylenedioxythiophene) (PEDOT) – are discussed with respect to their doping mechanisms, charge-transport behavior, optical properties, and mechanical performance. Molecular engineering strategies for optimizing backbone and side-chain architectures to enhance conductivity, stability, and functionality are examined. Applications of conducting polymers in emerging technologies such as organic photovoltaics, fuel cells, metal-free rechargeable batteries, supercapacitors, light-emitting diodes, sensors, and bioelectronic devices are reviewed. Recent advances in polymer – nanomaterial composites, machine-learning-assisted materials optimization, and scalable manufacturing approaches, particularly roll-to-roll processing, are highlighted as key developments addressing challenges related to environmental stability, film quality, and charge transport. Remaining limitations and future research directions for the large-scale commercialization of flexible, wearable, and sustainable electronic devices are identified.