Defect Engineering Boosted Ultrahigh Thermoelectric Power Conversion Efficiency in Polycrystalline SnSe

Vaithinathan Karthikeyan, Saw Lin Oo, James Utama Surjadi, Xiaocui Li, Vaskuri C.S. Theja, Venkataramanan Kannan, Siu Chuen Lau, Yang Lu, Kwok Ho Lam, Vellaisamy A.L. Roy

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

Two-dimensional (2D)-layered atomic arrangement with ultralow lattice thermal conductivity and ultrahigh figure of merit in single-crystalline SnSe drew significant attention among all thermoelectric materials. However, the processing of polycrystalline SnSe with equivalent thermoelectric performance as single-crystal SnSe will have great technological significance. Herein, we demonstrate a high zT of 2.4 at 800 K through the optimization of intrinsic defects in polycrystalline SnSe via controlled alpha irradiation. Through a detailed theoretical calculation of defect formation energies and lattice dynamic phonon dispersion studies, we demonstrate that the presence of intrinsically charged Sn vacancies can enhance the power factor and distort the lattice thermal conductivity by phonon-defect scattering. Supporting our theoretical calculations, the experimental enhancement in the electrical conductivity leads to a massive power factor of 0.9 mW/mK2 and an ultralow lattice thermal conductivity of 0.22 W/mK through the vacancy-phonon scattering effect on polycrystalline SnSe. The strategy of intrinsic defect engineering of polycrystalline thermoelectric materials can increase the practical implementation of low-cost and high-performance thermoelectric generators.

Original languageEnglish
Pages (from-to)58701-58711
Number of pages11
JournalACS Applied Materials and Interfaces
Volume13
Issue number49
DOIs
Publication statusPublished - 15 Dec 2021

Keywords

  • alpha irradiation
  • defect engineering
  • lattice thermal conductivity
  • phonon scattering
  • thermoelectrics

ASJC Scopus subject areas

  • Materials Science(all)

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