All-Scale Hierarchically Structured p-Type PbSe Alloys with High Thermoelectric Performance Enabled by Improved Band Degeneracy

Gangjian Tan*, Shiqiang Hao, Songting Cai, Trevor P. Bailey, Zhongzhen Luo, Ido Hadar, Ctirad Uher, Vinayak P Dravid, Christopher M Wolverton, Mercouri Kanatzidis

*Corresponding author for this work

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We show an example of hierarchically designing electronic bands of PbSe toward excellent thermoelectric performance. We find that alloying 15 mol % PbTe into PbSe causes a negligible change in the light and heavy valence band energy offsets (ΔEV) of PbSe around room temperature; however, with rising temperature it makes ΔEV decrease at a significantly higher rate than in PbSe. In other words, the temperature-induced valence band convergence of PbSe is accelerated by alloying with PbTe. On this basis, applying 3 mol % Cd substitution on the Pb sites of PbSe0.85Te0.15 decreases ΔEV and enhances the Seebeck coefficient at all temperatures. Excess Cd precipitates out as CdSe1-yTey, whose valence band aligns with that of the p-type Na-doped PbSe0.85Te0.15 matrix. This enables facile charge transport across the matrix/precipitate interfaces and retains the high carrier mobilities. Meanwhile, compared to PbSe the lattice thermal conductivity of PbSe0.85Te0.15 is significantly decreased to its amorphous limit of 0.5 W m-1 K-1. Consequently, a highest peak ZT of 1.7 at 900 K and a record high average ZT of ∼1 (400-900 K) for a PbSe-based system are achieved in the composition Pb0.95Na0.02Cd0.03Se0.85Te0.15, which are ∼70% and ∼50% higher than those of Pb0.98Na0.02Se control sample, respectively.

Original languageEnglish (US)
Pages (from-to)4480-4486
Number of pages7
JournalJournal of the American Chemical Society
Volume141
Issue number10
DOIs
StatePublished - Mar 13 2019

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Valence bands
Alloying
Precipitates
Temperature
Seebeck coefficient
Carrier mobility
Charge transfer
Thermal conductivity
Substitution reactions
Thermal Conductivity
lead selenide
Chemical analysis
Light

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Tan, Gangjian ; Hao, Shiqiang ; Cai, Songting ; Bailey, Trevor P. ; Luo, Zhongzhen ; Hadar, Ido ; Uher, Ctirad ; Dravid, Vinayak P ; Wolverton, Christopher M ; Kanatzidis, Mercouri. / All-Scale Hierarchically Structured p-Type PbSe Alloys with High Thermoelectric Performance Enabled by Improved Band Degeneracy. In: Journal of the American Chemical Society. 2019 ; Vol. 141, No. 10. pp. 4480-4486.
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abstract = "We show an example of hierarchically designing electronic bands of PbSe toward excellent thermoelectric performance. We find that alloying 15 mol {\%} PbTe into PbSe causes a negligible change in the light and heavy valence band energy offsets (ΔEV) of PbSe around room temperature; however, with rising temperature it makes ΔEV decrease at a significantly higher rate than in PbSe. In other words, the temperature-induced valence band convergence of PbSe is accelerated by alloying with PbTe. On this basis, applying 3 mol {\%} Cd substitution on the Pb sites of PbSe0.85Te0.15 decreases ΔEV and enhances the Seebeck coefficient at all temperatures. Excess Cd precipitates out as CdSe1-yTey, whose valence band aligns with that of the p-type Na-doped PbSe0.85Te0.15 matrix. This enables facile charge transport across the matrix/precipitate interfaces and retains the high carrier mobilities. Meanwhile, compared to PbSe the lattice thermal conductivity of PbSe0.85Te0.15 is significantly decreased to its amorphous limit of 0.5 W m-1 K-1. Consequently, a highest peak ZT of 1.7 at 900 K and a record high average ZT of ∼1 (400-900 K) for a PbSe-based system are achieved in the composition Pb0.95Na0.02Cd0.03Se0.85Te0.15, which are ∼70{\%} and ∼50{\%} higher than those of Pb0.98Na0.02Se control sample, respectively.",
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All-Scale Hierarchically Structured p-Type PbSe Alloys with High Thermoelectric Performance Enabled by Improved Band Degeneracy. / Tan, Gangjian; Hao, Shiqiang; Cai, Songting; Bailey, Trevor P.; Luo, Zhongzhen; Hadar, Ido; Uher, Ctirad; Dravid, Vinayak P; Wolverton, Christopher M; Kanatzidis, Mercouri.

In: Journal of the American Chemical Society, Vol. 141, No. 10, 13.03.2019, p. 4480-4486.

Research output: Contribution to journalArticle

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AU - Tan, Gangjian

AU - Hao, Shiqiang

AU - Cai, Songting

AU - Bailey, Trevor P.

AU - Luo, Zhongzhen

AU - Hadar, Ido

AU - Uher, Ctirad

AU - Dravid, Vinayak P

AU - Wolverton, Christopher M

AU - Kanatzidis, Mercouri

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N2 - We show an example of hierarchically designing electronic bands of PbSe toward excellent thermoelectric performance. We find that alloying 15 mol % PbTe into PbSe causes a negligible change in the light and heavy valence band energy offsets (ΔEV) of PbSe around room temperature; however, with rising temperature it makes ΔEV decrease at a significantly higher rate than in PbSe. In other words, the temperature-induced valence band convergence of PbSe is accelerated by alloying with PbTe. On this basis, applying 3 mol % Cd substitution on the Pb sites of PbSe0.85Te0.15 decreases ΔEV and enhances the Seebeck coefficient at all temperatures. Excess Cd precipitates out as CdSe1-yTey, whose valence band aligns with that of the p-type Na-doped PbSe0.85Te0.15 matrix. This enables facile charge transport across the matrix/precipitate interfaces and retains the high carrier mobilities. Meanwhile, compared to PbSe the lattice thermal conductivity of PbSe0.85Te0.15 is significantly decreased to its amorphous limit of 0.5 W m-1 K-1. Consequently, a highest peak ZT of 1.7 at 900 K and a record high average ZT of ∼1 (400-900 K) for a PbSe-based system are achieved in the composition Pb0.95Na0.02Cd0.03Se0.85Te0.15, which are ∼70% and ∼50% higher than those of Pb0.98Na0.02Se control sample, respectively.

AB - We show an example of hierarchically designing electronic bands of PbSe toward excellent thermoelectric performance. We find that alloying 15 mol % PbTe into PbSe causes a negligible change in the light and heavy valence band energy offsets (ΔEV) of PbSe around room temperature; however, with rising temperature it makes ΔEV decrease at a significantly higher rate than in PbSe. In other words, the temperature-induced valence band convergence of PbSe is accelerated by alloying with PbTe. On this basis, applying 3 mol % Cd substitution on the Pb sites of PbSe0.85Te0.15 decreases ΔEV and enhances the Seebeck coefficient at all temperatures. Excess Cd precipitates out as CdSe1-yTey, whose valence band aligns with that of the p-type Na-doped PbSe0.85Te0.15 matrix. This enables facile charge transport across the matrix/precipitate interfaces and retains the high carrier mobilities. Meanwhile, compared to PbSe the lattice thermal conductivity of PbSe0.85Te0.15 is significantly decreased to its amorphous limit of 0.5 W m-1 K-1. Consequently, a highest peak ZT of 1.7 at 900 K and a record high average ZT of ∼1 (400-900 K) for a PbSe-based system are achieved in the composition Pb0.95Na0.02Cd0.03Se0.85Te0.15, which are ∼70% and ∼50% higher than those of Pb0.98Na0.02Se control sample, respectively.

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