2, University of California, Davis, Davis, California, United States
Thermoelectric materials have been investigated for producing green energy through the conversion of waste heat generated from cars and other large machinery into electricity. The efficiency of these materials partially depends on having high electrical conductivity in conjunction with low thermal conductivity. Unfortunately, these two parameters are often coupled. In complex crystals, the Phonon Glass-Electron Crystal concept describes a structure that allows for the decoupling of electrical and thermal conductivities. A new family of Cs0.16MxSi1-xAs2 (M = Cu, Zn, Ga) compounds has been synthesized. All compounds are isostructural and crystallize in the orthorhombic Pnma space group (No. 62). These compounds consist of (Si/M)1As2 layers with Cs cations situated in large channels between the layers. Metals of Cu, Zn, and Ga substitute Si atoms for charge balance and allow properties to be tuned. The crystal structure complies with the Phonon Glass-Electron Crystal concept as the (Si/M)1As2 layers encourage electronic conductivity and the rattling Cs ions scatter phonons. Synthesis, structure, and thermoelectric properties for these compounds will be discussed.