Adjustable effects of zinc substitution for indium on the thermoelectric properties of p-type CuInSe2.02

In this study, the thermoelectric properties of Zn-doped CuInSe2.02 (CuIn1-xZnxSe2.02, 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 CuIn0.98Zn0.02Se2.02 at 430 K. In addition, the thermal conductivity of Zn-doped CuInSe2.02 bulk materials have a slight suppression. Thus, the CuIn0.98Zn0.02Se2.02 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 CuInSe2.02. The present work indicates that the substitution of In by Zn would be a promising means to improve thermoelectric properties of CuInSe2.02. •Small amount of Zn substitution for In could increase the electrical conductivity and Seebeck coefficient.•Change the electrical conduction mechanism of CuInSe2 from two-charge carrier behavior to hole dominated behavior.•The CuIn0.98Zn0.02Se2.02 achieves the highest peak ZT of 0.18, which is twice larger than that of pristine CuInSe2.02.