Thermoelectric properties of Sr-doped LSCO for energy harvesting applications below room temperature

Thermoelectric properties of polycrystalline La2CuO4 with (x = 0.0, 0.02, 0.05, 0.10, 0.15, 0.20) have been examined. For this, the samples have been synthesised via solid-state reaction (SSR) technique. For microstructural analysis of investigated pellets, X-ray diffraction and scanning electron microscopy have been performed. The electrical resistivity and Seebeck coefficient of the investigated samples have been measured with the help of an in-house fabricated setup, capable to measure the resistivity and thermopower between 100 and 400 K with +/- 3% experimental uncertainty. The electrical resistivity reveals a semiconducting nature for pristine pellets. However, a transition to metallic nature of electrical resistivity is observed for Sr doping concentration >= 0.02. The Seebeck coefficient (S) of investigated pellets is found to be positive, which indicates holes type conduction. Apart from that, a gradual decrease in the Seebeck coefficient has also been noticed as Sr dose increases. Again, the sample with Sr concentration x = 0.02 is found to be the best with a maximum power factor value (6.947 mu W/cm K-2) at 165 K, which is a positive sign for future applicability of LSCO-based oxide materials for energy harvesting applications below room temperature.