A facile synthesis of hierarchical Cu2NiSnS4 nanostructures with low thermal conductivity for thermoelectric applications

Abstract

In recent decades, quaternary chalcogenides have shown enhanced thermoelectric performance due to their low thermal conductivity. In the present work, we report the thermoelectric properties of flower like Cu2NiSnS4 sample prepared at different growth periods by solvothermal method. The structural, morphological, thermal and thermoelectric properties of Cu2NiSnS4 have been investigated. The XRD analysis confirms the formation of Cu2NiSnS4. HR-SEM analysis reveals that the growth period effectively changes the spherical morphology into hierarchical structures. The prepared Cu2NiSnS4 sample at 48 ​h show low electrical resistivity of 1.14 ​× ​10−3 ​Ω ​m and high Seebeck coefficient of 179.43 ​μVK−1. The 48-h grown sample with hierarchical structures exhibit low thermal conductivity of 0.3454 ​W ​m−1K−1 ​at 478 ​K compared to other samples. Therefore, sample grown for 48 ​h shows the high-power factor of 27.84μWm−1K−2 and high figure of merit of (zT) 0.038 ​at 478 ​K compared with others samples. Cu2NiSnS4 prepared for 48 ​h indicates promising thermoelectric applications, bestowing to the results of the experiments.