Experimental and simulated studies on thin-film thermoelectric generator insensitive to tensile strain

Thermoelectric power generation has attracted significant interest for its capability to directly convert thermal energy into electricity. Among various configurations, thin-film thermoelectric generators (TEGs) stand out due to their lightweight nature and facile integration, offering promising applications in waste heat recovery and wearable electronics. However, the performance of such devices under complex mechanical conditions, particularly under biaxial tensile strain, remains underexplored. In this work, we designed and fabricated a thin-film TEG insensitive to tensile strain and performed a parametric analysis using validated 3D numerical simulations to evaluate the effects of environmental conditions, material properties, and geometric parameters. Notably, the designed device maintained stable electrical performance under various biaxial tensile strains. Owing to its miniature and thin profile, variations in any component of the generator significantly affected its electrical performance. The results indicated that reduced thermal conductivity of the substrate and Ecoflex layer, as well as a thinner substrate, enhance the output voltage. Furthermore, longer thermoelectric legs within a certain range contributed to higher output voltage. Higher output voltage was more readily achieved when the inner radius length was close to the radius of the heat source. This work provides valuable insights for the development of high-performance compliant TEGs applicable in dynamic mechanical environments, such as complex stretching in the back and shoulder–elbow regions induced by human motion.