Optical and thermoelectric properties of NaNbO3 thin film deposed by spray pyrolysis: experimental and DFT study

Thermoelectric materials are gaining popularity as one of the most effective solutions to the energy issue because of their capacity to create electricity from waste heat without polluting the environment. In this work, we interest in the thermoelectric properties in NaNbO 3 thin film prepared by sol–gel method and deposited by spray pyrolysis. The structural analyze using X-ray diffraction proves an ideal Pm 3 ¯ m cubic structure. Using UV–visible spectroscopy analysis, we found that the studied material is a semiconductor material with a direct band gap Eg = 1.29 eV. Thanks to the structure of the electronic bands extracted using DFT calculation, we have estimated the charge carrier densities Nc and Nv (Nc = 4.91 × 10 19 cm −3 and Nv = 8.37 × 1019 cm −3 ). Using the semi-classical Boltzmann theory, thermal, electrical and thermoelectric properties were investigated. An interesting result was obtained which makes consider NaNbO 3 a promising candidate that could be used for thermoelectric devices.