Adjustable effects of zinc substitution for indium on the thermoelectric properties of p-type CuInSe_2.02

In this study, the thermoelectric properties of Zn-doped CuInSe_2.02 (CuIn_1-xZn_xSe_2.02, x = 0, 0.01, 0.02, 0.03, 0.05, 0.07) at the temperatures from 323 K to 773 K have been investigated. The results indicate that small amount of Zn substitution for In could increase the electrical conductivity and Seebeck coefficient simultaneously, lead to a high power factor of 0.21 mW m⁻¹ K⁻² for CuIn_0.98Zn_0.02Se_2.02 at 430 K. In addition, the thermal conductivity of Zn-doped CuInSe_2.02 bulk materials have a slight suppression. Thus, the CuIn_0.98Zn_0.02Se_2.02 achieves the highest peak ZT of 0.18 at 773 K due to the synergistically optimized electrical and thermal transport properties, which is twice larger than that of pristine CuInSe_2.02. The present work indicates that the substitution of In by Zn would be a promising means to improve thermoelectric properties of CuInSe_2.02.