Liquid–Solid Interface Reactions Drive Enhanced Thermoelectric Performance in Ag<sub>2</sub>Se
Yu Liu, Tobias Kleinhanns, Sharona Horta, Ewelina P. Dutkiewicz-Kopczynska, Shaoqing Lu, María Chiara Spadaro, Aziz Genç, Lei Chen, Khak Ho Lim, Min Hong, Jordi Arbiol, María Ibáñez
Abstract
High Resolution Image Download MS PowerPoint Slide Ag 2 Se is a promising n-type thermoelectric material, but its performance is limited by excessive carrier concentration, compositional inhomogeneity, and phase instability, challenges rooted in a narrow homogeneity range and uncontrolled Ag + diffusion in the superionic phase. Here, we address these issues by exploiting liquid–solid interface reactions using CdSe complexes that remove surface excess Ag to yield stoichiometric Ag 2 Se and generate CdSe nanodomains that inhibit Ag + diffusion and constrain grain growth. The resulting Ag 2 Se-CdSe nanocomposites exhibit a reproducible, stable figure of merit ( zT ) of 1.04 between 300 and 390 K. Beyond demonstrating high performance, we elucidate the interfacial chemical reactions that give rise to the observed microstructure and transport properties, providing a foundation for rationally engineering interfacial chemistry to tailor transport properties across diverse thermoelectric material systems.