Effect of Copper Stoichiometry on the Thermoelectric Properties of Cu4+xTiSe4

This study aimed to investigate the thermoelectric properties of Cu 4+ x TiSe 4 ( x  = −0.04, −0.02, 0, +0.02, and +0.04) as a potential candidate for energy conversion applications. High-purity precursor materials were used to prepare specimens by solid-state reaction, followed by ball milling and hot pressing. X-ray diffraction analysis confirmed a cubic crystal structure with a lattice parameter of about 11.288 Å. Raman spectroscopy revealed unique vibrational modes associated with the Cu 4 TiSe 4 phase. Scanning electron microscopy and energy-dispersive x-ray spectroscopy revealed homogeneous microstructures with variable elemental compositions that corresponded to the expected stoichiometry. Electrical transport measurements revealed that the Cu-deficient sample ( x  = −0.04) possessed the lowest resistivity and the highest Seebeck coefficient, leading to a power factor of 44.4 μW/mK 2 . The Cu-rich sample demonstrated the lowest lattice thermal conductivity of 0.51 W/mK at 624 K. This underlines the significant impact of precise stoichiometric control on electrical and thermal transport characteristics, establishing Cu 4 TiSe 4 as a promising material for further research toward advanced energy conversion technologies.