Enhancing thermoelectric properties of CuNiO thin films through post-annealing: Effect on Seebeck coefficient and power generation

The need for the best thermoelectric power generation to extract low-grade heat energy from the human body has generated considerable interest. However, developing oxide-based thermoelectric materials with both high stability and Seebeck coefficient remains challenging. In this work, we have prepared CuNiO thin film with an economical and simple thermal evaporation method and post-annealed at different temperatures from 400 to 550 °C. XRD and SEM have determined the crystal structure and surface morphology of the CuNiO thin film. The electrical conductivity and charge carrier concentration increase with post-annealing temperature due to the formation of the secondary phases. The Seebeck coefficient has decreased from 65.1 to 37.9 µV/K with post-annealing temperature due to improved charge carrier density, the electronic band structure of the material and secondary phases. The maximum power factor has been achieved in the unannealed sample.