Improvement of thermoelectric properties of sol gel grown Cu2Zn1-xSnS4 thin films with the incorporation of Cd atoms

Abstract

In this manuscript, we have reported the thermo-electric (TE) properties of Cu2Zn1-xCdxSnS4 thin films grown by a sol - gel method. Various thermoelectric properties such as Seebeck coefficient, electrical conductivity and power factor of host CZTS were found to be increased (536 μV/°C, 227 S/cm and 6.3 × 10−3 Wm−1C−2 respectively) with Cd incorporation. The enhancement in the thermo-electric properties is due to the fact that the density of electrons is shifted towards the Cu atoms which is responsible for the development of copper-based secondary phases. The development of secondary phases with Cd atoms resulted in the enhancement of Seebeck coefficient and electrical conductivity simultaneously. This argument was justified by some supplementary measurements such as XRD, Raman Spectroscopy and Scanning Electron Microscopy. XRD and Raman data suggested the development of secondary phases with the concentration of Cd atoms in the crystal of CZTS. SEM images demonstrated the irregular formation of grain structure with nano and microscale sizes.