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.