Enhanced Thermoelectric Performance of Cu₂Se Alloys by Simultaneous Engineering of Thermal and Electrical Transport Properties through S and Te Co‐Doping

Cu₂Se‐based binary compounds have recently fetched the attention of researchers due to their remarkable electrical and extremely low thermal properties. In addition, Cu₂Se‐based quaternary chalcogenides are expected to present exceptional thermoelectric performance. Cu₂Se_1−x−yS_xTe_y‐like compounds are synthesized via microwave‐assisted hydrothermal method and their respective thermal and electrical transport properties are studied in this research work. The phase purity and homogeneity are examined by X‐ray diffraction and energy‐dispersive X‐ray spectrometry analysis. The introduction of S and Te elements into Cu₂Se matrix enhances Seebeck coefficient resulting in improved electrical performance illustrating a maximum power factor of 989.4 μWK⁻² m⁻¹ at 673 K. Furthermore, S‐ and Te‐co‐doped samples exhibit reduced total thermal conductivity values with lowest value of 0.808 WK⁻¹ m⁻¹ for Cu₂Se_0.96S_0.02Te_0.02 sample in comparison to 1.18 WK⁻¹ m⁻¹ for the pristine sample. The simultaneous improvement in electrical and thermal properties results in enhanced figure of merit of 0.82 for Cu₂Se_0.96S_0.02Te_0.02 sample at 673 K.