Electronic Materials Letters

, Volume 14, Issue 5, pp 556–562 | Cite as

Low Thermal Conductivity of RE-Doped SrO(SrTiO3)1 Ruddlesden Popper Phase Bulk Materials Prepared by Molten Salt Method

  • Yulia Eka Putri
  • Suhana Mohd Said
  • Refinel Refinel
  • Michitaka Ohtaki
  • Syukri Syukri


The SrO(SrTiO3)1 (Sr2TiO4) Ruddlesden Popper (RP) phase is a natural superlattice comprising of alternately stacking perovskite-type SrTiO3 layers and rock salt SrO layers along the crystallographic c direction. This paper discusses the properties of the Sr2TiO4 and (La, Sm)-doped Sr2TiO4 RP phase synthesized via molten salt method, within the context of thermoelectric applications. A good thermoelectric material requires high electrical conductivity, high Seebeck coefficient and low thermal conductivity. All three conditions have the potential to be fulfilled by the Sr2TiO4 RP phase, in particular, the superlattice structure allows a higher degree of phonon scattering hence resulting in lowered thermal conductivity. In this work, the Sr2TiO4 RP phase is doped with Sm and La respectively, which allows injection of charge carriers, modification of its electronic structure for improvement of the Seebeck coefficient, and most significantly, reduction of thermal conductivity. The particles with submicron size allows excessive phonon scattering along the boundaries, thus reduces the thermal conductivity by fourfold. In particular, the Sm-doped sample exhibited even lower lattice thermal conductivity, which is believed to be due to the mismatch in the ionic radius of Sr and Sm. This finding is useful as a strategy to reduce thermal conductivity of Sr2TiO4 RP phase materials as thermoelectric candidates, by employing dopants of differing ionic radius.


Superlattice Perovskite Ruddlesden Popper phase Molten salt Electrical conductivity 



The work was supported by Ministry of Research, Technology and Higher Education of the Republic Indonesia through Research Institute and Community Service (Riset Dasar Grant No. 19/UN.16.03.D/PP/FMIPA/2017) and Domestic Seminar Assistance Program of Andalas University.


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Copyright information

© The Korean Institute of Metals and Materials 2018

Authors and Affiliations

  • Yulia Eka Putri
    • 1
  • Suhana Mohd Said
    • 2
  • Refinel Refinel
    • 1
  • Michitaka Ohtaki
    • 3
  • Syukri Syukri
    • 1
  1. 1.Department of Chemistry, Faculty of Mathematics and Natural SciencesAndalas UniversityPadangIndonesia
  2. 2.Department of Electrical Engineering, Faculty of EngineeringUniversity of MalayaKuala LumpurMalaysia
  3. 3.Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering SciencesKyushu UniversityFukuokaJapan

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