Preparation and Thermoelectric Performance of Tellurium Nanowires-based Thin-Film Materials

Abstract

Flexible thermoelectric devices have received a great deal of interest due to their capability of direct convert human body heat into electrical energy. In this work, we synthesized the tellurium nanowires by using hydrothermal method. The effects of hydrothermal temperature and reducibility of the reaction solution (with or without ascorbic acid) on morphology and thermoelectric properties of tellurium nanowires were investigated. Compared to the nanowires prepared in strong reducing solution, those prepared in relatively weak reducing solution (without ascorbic acid) reveal a higher aspect ratio up to 200 and the as-assembled film exhibits better electrical conductivity up to 26 S•m-1. It is also found that the wet-press method can enhance the micro-densification of the film, resulting in a tighter connection among the micro-nanowires. Therefore, the carrier mobility and carrier concentration of the tellurium nanowire film are significantly increased. As a result, its electrical conductivity is improved by 18.3 times, reached 476 S∙m-1. Simultaneously the optimal tellurium nanowire film exhibits good performances including Seebeck coefficient (282.9 μV∙K-1) and power factor (38 μW∙m-1∙K-2).