Advances in thermoelectronic materials and devices for self-sustaining wearable and IoT systems

Thermoelectric devices that facilitate the conversion of low-grade thermal gradients into electrical energy are increasingly recognized as essential elements for self-sustaining wearable electronics and autonomous Internet of Things (IoT) infrastructures. This review provides a comprehensive evaluation of recent advancements in thermoelectric materials, flexible device architectures, and system-level power management methodologies that have been documented over the past five years. Principal areas of emphasis encompass nanostructuring, band engineering, and defect modulation strategies that augment the thermoelectric figure of merit (ZT) and power factor under low-ΔT conditions. Innovations in conducting polymers, hybrid nanocomposites, and low-dimensional materials are underscored for their mechanical flexibility, stretchability, and compatibility with scalable processing techniques. Comparative assessments of benchmark materials, including Bi₂Te₃ alloys, SnSe, Poly(3,4-ethylenedioxythiophene) (PEDOT): poly(styrenesulfonate) (PSS), and Carbon nanotube (CNT)/polymer composites, are presented with direct correlations to device-level performance metrics relevant to wearable applications and distributed sensor networks. In addition to summarizing advancements, this review emphasizes that successful commercialization will depend on the coordinated optimization of high-ZT, low-toxicity materials, robust architectures, and ultra-low-power electronic systems. Challenges such as scalable synthesis, long-term thermomechanical reliability, and sustainable recycling practices are critically scrutinized. Furthermore, the review aligns prospective research trajectories with Sustainable and Affordable and Clean Energy by promoting battery-free, environmentally sustainable wearable and IoT technologies.