Enhancement of thermoelectric properties of La-doped SrTiO ₃ bulk by introducing nanoscale porosity

Abstract

Electron-doped SrTiO3 is a well-known n-type thermoelectric material, although the figure of merit of SrTiO3 is still inferior compared with p-type metal oxide-based thermoelectric materials due to its high lattice thermal conductivity. In this study, we have used a different amount of the non-ionic surfactant F127 during sample preparation to introduce nanoscale porosities into bulk samples of La-doped SrTiO3. It has been observed that the porosities introduced into the bulk sample significantly improve the Seebeck coefficient and reduce the thermal conductivity by the charge carrier and phonon scattering respectively. Therefore, there is an overall enhancement in the power factor (PF) followed by a dimensionless figure of merit (zT) over a wide scale of temperature. The sample 20 at% La-doped SrTiO3 with 600 mg of F127 surfactant (SLTO 600F127) shows the maximum PF of 1.14 mW m−1 K−2 at 647 K which is 35% higher than the sample without porosity (SLTO 0F127), and the same sample (SLTO 600F127) shows the maximum value of zT is 0.32 at 968 K with an average enhancement of 62% in zT in comparison with the sample without porosity (SLTO 0F127).

Significant Reduction in Thermal Conductivity and Improved Thermopower of Electron‐Doped Ba1–xLaxTiO3 with Nanostructured Rectangular Pores

“…The synthesis protocol of powders with nano‐scale porosity was already discussed in detail in a previous publication. [ 18 ] The sample was denoted as 20L BTO F127 based on La doping amount (20 at%) and the name of the surfactant, F127.…”

“…Previously, we have reported that La doping optimization and nanostructured porosity into bulk material can improve the TE properties of SrTiO 3 . [ 18,19 ] BaTiO 3 has a similar cubic perovskite structure above the Curie temperature. It has intrinsically low thermal conductivity and chemical stability at high temperatures.…”

Review on grain size effects on thermal conductivity in ZnO thermoelectric materials

“…Nanoscale constituent-induced quantum connement can be employed to improve the Seeback coefficient, whereas, enhanced phonon scattering by the interfacial structure surfaces in the nanostructures can be employed to reduce their thermal conductivity. 38 These interfacial structure surfaces can be referred to as grain boundaries in nanostructured materials. The effects of grain boundary on thermal conductivity by phonon scattering has been described by Callaway, 39,40 which is expressed as:…”

New Design of Solar Photovoltaic and Thermal Hybrid System for Performance Improvement of Solar Photovoltaic

“…Among various PVT systems such as air, water, air/water, phase change material (PCM), and nanofluid, it is found that the air heater PVT system is promising for future preheating air applications [17]. The PVT system has the potential to integrate thermoelectric generator with the system to produce electricity from the thermal energy that is extracted from the solar panel [18,19].…”