Synthesis of Non-uniformly Pr-doped SrTiO3 Ceramics and Their Thermoelectric Properties.
We demonstrate a novel synthesis strategy for the preparation of Pr-doped SrTiO3 ceramics via a combination of solid state reaction and spark plasma sintering techniques. Polycrystalline ceramics possessing a unique morphology can be achieved by optimizing the process parameters, particularly spark plasma sintering heating rate. The phase and morphology of the synthesized ceramics were investigated in detail using X-ray diffraction, scanning electron microcopy and energy-dispersive X-ray spectroscopy. It was observed that the grains of these bulk Pr-doped SrTiO3 ceramics were enhanced with Pr-rich grain boundaries. Electronic and thermal transport properties were also investigated as a function of temperature and doping concentration. Such a microstructure was found to give rise to improved thermoelectric properties. Specifically, it resulted in a significant improvement in carrier mobility and the thermoelectric power factor. Simultaneously, it also led to a marked reduction in the thermal conductivity. As a result, a significant improvement (> 30%) in the thermoelectric figure of merit was achieved for the whole temperature range over all previously reported maximum values for SrTiO3-based ceramics. This synthesis demonstrates the steps for the preparation of bulk polycrystalline ceramics of non-uniformly Pr-doped SrTiO3.
Department of Materials Science and Engineering, Clemson University; amehdiz@g.clemson.edu.
Arash
A
Mehdizadeh Dehkordi
Department of Physics and Astronomy, Clemson University.
Sriparna
S
Bhattacharya
Electron Microscope Facility, Clemson University.
Taghi
T
Darroudi
Department of Physics and Astronomy, Clemson University.
Xiaoyu
X
Zeng
Materials Science and Engineering, King Abdullah University of Science and Technology.
Husam N
HN
Alshareef
Department of Materials Science and Engineering, Clemson University; Department of Physics and Astronomy, Clemson University.
Terry M
TM
Tritt
D002516:Ceramics / Q000138:chemical synthesis* / Q000737:chemistry; D004583:Electrons; D010087:Oxides / Q000138:chemical synthesis* / Q000737:chemistry; D011221:Praseodymium / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry; D013696:Temperature; D013814:Thermal Conductivity; D014025:Titanium / Q000737:chemistry; D014961:X-Ray Diffraction
D010087:Oxides; D014025:Titanium; D011221:Praseodymium; C119252:strontium titanium oxide; D013324:Strontium