Thermoelectric Conversion Efficiency of 4% in Environmental-Friendly Kesterite Single Crystal

Abstract

Multinary Cu2ZnSnS4 (CZTS)-based materials have attracted considerable attention for thermoelectric (TE) power generation owing to their cost-effectiveness and abundance. The device structure of the CZTS/Au diffusion barrier layer was effective in impeding chemical diffusion during operation; however, its interfacial contact resistance was relatively higher than that of the Bi2Te3 device. We report the discovery of p-type CZTS single crystals with a record-high dimensionless figure of merit (ZT) of 1.6 at 800 K and TE conversion efficiency of ∼4% at a temperature difference of 473 K, which is based on the Te-free concept. This study demonstrated the potential of CZTS-based TE materials for environment-friendly TE power generation.