(186y) Facile Method to Fabricate Nanostructured Silver Selenide Thin Films at Room Temperature from a Copper Selenide Template

Ag₂Se is a promising n-type candidate for thermoelectric applications. Nanostructured Ag₂Se reduces the thermal conductivity and increases Seebeck coefficient due to the grain boundaries between the nanoparticles. In contrast to other complex and expensive methods of synthesizing Ag₂Se, our group reports a facile and efficient strategy of fabricating nanostructures Ag₂Se thin films via ion exchange technique at room temperature. Starting from a cubic-phase Cu_2-xSe template prepared by thiol-amine dissolution process, Ag₂Se thin films were created by simply soaking our Cu_2-xSe thin films into a Ag⁺ ion solution for a short amount of time while maintaining the morphology of Cu_2-xSe thin films. The transition from Cu_2-xSe matrix to post-soaked Ag₂Se thin films was justified through the phase change and compositions analyzed by X-ray diffraction (XRD) and Energy Dispersive X-Ray Spectroscopy (EDS). This safe and solution-processable reaction yields to Ag₂Se thin films with a power factor of 350. The reaction process is far more economical, facilitating the scale-up to production, compared to other Ag₂Se nanoparticle fabrication processes, such as Schlenk line synthesis and chemical vapor deposition. We aim to improve the power factor via methods such as elemental doping, atomic layer deposition, and energy filtering. Most importantly, this method of template nanostructures provides a framework for exploring a wide range of thermoelectric materials beyond Ag₂Se thin films.