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

Abstract

Thermoelectric properties of polycrystalline La 2 CuO 4 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 μW/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.

Thermoelectric properties of La1.96Sr0.04CuO4 for energy harvesting and storage applications

“…In order to calculate the activation energy, ln(ρ) has been plotted as a function of (1/T) in Figure 2B, and the linear zone of the curve is fitted with the Arrhenius equation. The value of E g calculated from the slope of the curve is found to be 7.8 meV, which is in accordance with the previous reports 4, 28 and indicates that Sr substitution at La sites modifies carrier concentration. 29 The variation of the Seebeck coefficient (S) as a function of absolute temperature is shown in Figure 3A.…”