Thermoelectric Nanocomposites and Segmented Single-Leg Device Based on GeTe and (Bi,Sb)2Te3

Thermoelectric (TE) materials offer a promising route for direct thermal-to-electrical energy conversion via the Seebeck effect. Among them, GeTe exhibits superior performance in the mid-temperature range (500–800 K), whereas (Bi,Sb)2Te3is widely regarded as the benchmark material for near low-temperature applications (< 450 K). To improve TE efficiency over a wider temperature range, segmented GeTe/(Bi,Sb)2Te3-based single-leg TE devices were developed. Specifically, based on nanocomposite technology, B4C and SiC nanoparticles were, respectively, introduced into GeTe and (Bi,Sb)2Te3, achieving optimization of electrical conductivity alongside reduction in thermal conductivity, thereby enhancing the thermoelectric figure of merit (ZT). Finite element simulations were used to optimize the geometric structure of the segmented device, determining the ideal ratio of GeTe to (Bi,Sb)2Te3. The simulations predicted a maximum conversion efficiency (ηmax) of 16.9% when the ratio of GeTe to (Bi,Sb)2Te3was 0.24, with a power density of 18.5 mW/mm2. Experimentally, the fabricated segmented device attained a peak conversion efficiency of 7.14% and a power density of 12.5 mW/mm2under a hot-side temperature of 773 K. These findings confirm that strategic segmentation, combined with nanoscale phonon scattering engineering, substantially improves overall TE device performance across broad temperature range, underscoring its potential for high-efficiency thermoelectric energy conversion systems.