Microstructural and Thermoelectric Evolution of Ag 2 Se Under Controlled Annealing Conditions
Year: 2026
Type: article
Abstract: Harvesting waste heat near room temperature via thermoelectrics is technologically important, enabling energy recovery from sources such as the human body to power portable devices. Silver selenide (Ag 2 Se) is a promising candidate due to its high conversion efficiency in this range, yet reported performance varies widely with composition, microstructure, and processing. This study systematically investigates the influence of annealing conditions (temperature and atmosphere) on the microstructure and thermoelectric properties of Ag 2 Se. Results show that the annealing atmosphere (Ar or N 2 ) has negligible effect, while annealing temperature critically governs stoichiometry, grain size, and carrier concentration. Annealing at 200 °C produces Ag vacancies (Ag/Se < 2.0), which act as electron acceptors and reduce carrier concentration to near the optimal level. This enhances the Seebeck coefficient and power factor, yielding the highest figure of merit ( ZT ). In contrast, annealing at 300 °C (above the melting point of Se) induces partial Se evaporation, leading to Ag interstitials (Ag/Se > 2.0) that act as electron donors. This increases carrier concentration beyond the optimal range, reducing the power factor and ZT . Overall, precise control of annealing temperature is essential for microstructural engineering in Ag 2 Se, providing a practical pathway to optimize transport properties and enhance thermoelectric performance.
Source: ChemNanoMat
DOI: 10.1002/cnma.70363
Institution: Khon Kaen University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
Award: G3917161470
OpenAlex ID: W7208770705