Toward High-Power Output of Generators: High-Power-Factor Ag₂Te–Ag Thermoelectric Thin Films Using a Layer-by-Layer Method

The power factor is key to improving the performance of thin-film thermoelectric generators as power sources. The expected large power factor of Ag2Te testifies to its application potential. In this study, Ag2Te-Ag thin films were fabricated using a layer-by-layer method for controlling their composition and improving their thermoelectric properties. In contrast to the traditional low-temperature monoclinic structure, orthorhombic Ag2Te thin films with Ag nanoparticles on top were obtained by the reaction between Ag and Te nanorod thin films. Analysis of the structural and thermoelectric properties showed increased carrier concentration and enhanced electrical properties of the films, while the structural transition between the orthorhombic structure and the face-centered cubic structure improved the films' electrical stability over a wide range of temperatures. Owing to the special structure, a competitive high power factor of 4.66 mW m-1 K-2 at 668 K was achieved. The proposed approach improves the electrical properties of n-type Ag2Te thin films, owing to the special Ag2Te-Ag structure, and provides guidance for designing high-output-power thin-film thermoelectric generators.