TY - JOUR
T1 - Defect Engineering Boosted Ultrahigh Thermoelectric Power Conversion Efficiency in Polycrystalline SnSe
AU - Karthikeyan, Vaithinathan
AU - Oo, Saw Lin
AU - Surjadi, James Utama
AU - Li, Xiaocui
AU - Theja, Vaskuri C.S.
AU - Kannan, Venkataramanan
AU - Lau, Siu Chuen
AU - Lu, Yang
AU - Lam, Kwok Ho
AU - Roy, Vellaisamy A.L.
N1 - Funding Information:
We acknowledge grants from the Research Grants Council of Hong Kong Special Administrative Region Project no: T42-717/20 and Environmental and Conservation Fund (ECF) project number 44/2014. We thank Prof. Peter. K. N. Yu for providing the alpha particle irradiation source for the experiment.
Publisher Copyright:
©
PY - 2021/12/15
Y1 - 2021/12/15
N2 - 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.
AB - 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.
KW - alpha irradiation
KW - defect engineering
KW - lattice thermal conductivity
KW - phonon scattering
KW - thermoelectrics
UR - http://www.scopus.com/inward/record.url?scp=85120883358&partnerID=8YFLogxK
U2 - 10.1021/acsami.1c18194
DO - 10.1021/acsami.1c18194
M3 - Journal article
C2 - 34851624
AN - SCOPUS:85120883358
SN - 1944-8244
VL - 13
SP - 58701
EP - 58711
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 49
ER -