General Notices

The Department of Physics invites the campus community to a postgraduate seminar by Mr. Tauriel Jahoor on Thursday, June 11, 2026 at 10:45 a.m. The seminar will address the topic, Design, Fabrication & Thermoelectric Characterization of Perovskite Oxide Thin Films for Industrial Waste Heat Recovery.

Interested persons can attend in person at FST 414, 3rd Floor, Natural Sciences Building, Faculty of Science and Technology, or join via Zoom by clicking here

Abstract:

The global industrial processes reject an estimated 20-50% of energy input as wasted heat at a quantity of more than 200,000 PJ. Additional studies have found that these losses are through exhaust gases and heated surfaces across sectors including power generation, petrochemicals, cement, and metal processing, ranging from 200 to over 1400⁰C. Thermoelectric generators (TEGs) offer a solid-state, maintenance-free pathway for direct heat-to-electricity conversion. Conventional thermoelectric materials such as Bi₂Te₃, PbTe, and SiGe, while achieving a Figure of Merit, zT > 1, are limited by elemental toxicity, scarcity, and thermal degradation above 427^oC, restricting their deployment in high-grade industrial waste heat environments. Perovskite oxides present an alternative approach because they are oxidation-resistant, chemically stable beyond 727^oC, abundant, and non-toxic. However, existing studies report zT values well below 0.5, limiting their practical application. This research addresses the two performance limitations in SrTiO₃-based thin films: low electrical conductivity and high lattice thermal conductivity (κL). A-site substitution of Sr²⁺ with La³⁺ (x = 0, 0.05, 0.10, 0.15, 0.20 in LaxSr₁₋ₓTiO₃) introduces n-type carriers to enhance the power factor (S²σ), while 0.75 wt% graphene oxide (GO) nano-inclusions engineer interfacial phonon scattering to suppress κL. Films will be fabricated via sol-gel spin-coating onto LSAT 100 substrates at varying rpm, pyrolysed at 450°C, and annealed at 950°C in a reducing atmosphere. GO incorporation employs a solvent-exchange protocol transferring an aqueous GO dispersion into anhydrous 2-methoxyethanol, preventing Ti-precursor hydrolysis. Structural characterization will confirm phase purity and dopant distribution, while thermoelectric performance (Seebeck coefficient, electrical conductivity, thermal conductivity) will be evaluated up to 727^oC. This work aims to establish an optimized La-doping level at which GO nano-inclusions yield measurable zT enhancement, advancing a scalable, non-toxic thin-film platform for high-temperature industrial waste heat recovery.

Keywords: Thermoelectric generators, Waste heat recovery. Perovskite oxides. Strontium titanate, Spin Coating, Figure of merit (zT), Seebeck coefficient, Thermal Conductivity, Phonon scattering, Thin films, High-temperature thermoelectric.