Thermoelectric Performance of n-Type Argyrodite Ag8GeTe6 with Ultralow Lattice Thermal Conductivity and High Mobility Near Room Temperature
Year: 2026
Type: article
Abstract: Polycrystalline Ag₈GeTe₆ was synthesized by solid-state melting and spark plasma sintering, and its thermoelectric properties were investigated from 2 to 380 K. X-ray diffraction confirmed a cubic argyrodite structure with high phase purity, while diffuse reflectance spectra indicated a band gap of ~0.45 eV.Transport measurements revealed a semiconducting-to-metallic transition near 244 K. Hall data showed n-type conduction with carrier concentrations ~1017 cm-3 and exceptionally high room-temperature mobility (~3090 cm2 V-1 s-1).The Seebeck coefficient remained negative, reaching -140 µV/K at 380 K, with a power factor of 74 µWm-1K-2.The thermal conductivity was ultralow (0.13-0.33 W•m⁻¹•K⁻¹), dominated by a nearly temperature-independent lattice term arising from disordered Ag cations, consistent with phonon liquid-electron crystal behavior.Heat-capacity analysis confirmed low-energy Einstein modes consistent with localized vibrations.Compared with previous reports, the n-type Ag₈GeTe₆ synthesized in this work exhibits enhanced thermoelectric performance, achieving a maximum ZT of 0.10 at 380 K-approximately twice the previously reported value-due to the synergistic combination of ultralow lattice thermal conductivity, exceptionally high carrier mobility, and reduced electrical resistivity.
DOI: 10.36838/ijhsr810.77
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W7167676756