Thermoelectric Performance of CuInSe2-ZnSe Solid Solution

CuInSe2 is an N-type diamond-like semiconductors thermoelectric candidate for power generation at medium temperature with its environmentally friendly and cost-effective properties. However, the intrinsic high thermal conductivity of CuInSe2 limits the enhancement of its thermoelectric performance. Herein, we investigate the thermoelectric performance of N-type CuInSe2 materials by incorporating ZnSe through a solid solution strategy. A series of (CuInSe2)1-x(ZnSe)x (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) samples were synthesized, forming continuous solid solutions, while introducing minor porosity. ZnSe solid solution effectively reduces the lattice thermal conductivity of the CuInSe2 matrix at near-room temperatures, but has a weaker effect at higher temperatures. Due to the intrinsic low carrier concentration of the system, resulting in high resistivity, the maximum figure of merit (ZT) of (CuInSe2)0.8(ZnSe)0.2 reaches 0.08 at 773 K. Despite the relatively low ZT, the solid solution strategy proves effective in reducing the lattice thermal conductivity near-room temperature and offers potential for cost-effective thermoelectric materials.