Achieving high thermoelectric performance in Sb₂Se₃-alloyed GeTe through synergistic optimization of electrical and...

To address the key obstacles of high carrier concentration and high lattice thermal conductivity in p-type GeTe, we incorporated Sb₂Se₃ into the GeTe matrix for synergistic optimization. X-ray diffraction confirms that Sb incorporation promotes the rhombohedral-to-cubic phase transition, increasing band degeneracy and enhancing the Seebeck coefficient. Sb and Se co-doping tunes the hole carrier concentration to an optimal level while maintaining high carrier mobility, and jointly modulates the phonon band structure to strengthen phonon scattering and reduce sound velocity. Consequently, an ultralow lattice thermal conductivity of 0.36 W m^-1 K^-1 at 723 K and a peak zT of 2.22 are achieved. This work demonstrates the effectiveness of Sb₂Se₃ incorporation in regulating electronic and phononic transport, providing a viable strategy for designing high-performance lead-free thermoelectric materials.