TY  - JOUR
AU  - Zhou, Chongjian
AU  - Yu, Yuan
AU  - Lee, Yong Kyu
AU  - Cojocaru-Mirédin, Oana
AU  - Yoo, Byeongjun
AU  - Cho, Sung-Pyo
AU  - Im, Jino
AU  - Wuttig, Matthias
AU  - Hyeon, Taeghwan
AU  - Chung, In
TI  - High-Performance n-Type PbSe–Cu 2 Se Thermoelectrics through Conduction Band Engineering and Phonon Softening
JO  - Journal of the American Chemical Society
VL  - 140
IS  - 45
SN  - 1520-5126
CY  - Washington, DC
PB  - American Chemical Society
M1  - FZJ-2019-06550
SP  - 15535 - 15545
PY  - 2018
AB  - From a structural and economic perspective, tellurium-free PbSe can be an attractive alternative to its more expensive isostructural analogue of PbTe for intermediate temperature power generation. Here we report that PbSe0.998Br0.002-2%Cu2Se exhibits record high peak ZT 1.8 at 723 K and average ZT 1.1 between 300 and 823 K to date for all previously reported n- and p-type PbSe-based materials as well as tellurium-free n-type polycrystalline materials. These even rival the highest reported values for n-type PbTe-based materials. Cu2Se doping not only enhance charge transport properties but also depress thermal conductivity of n-type PbSe. It flattens the edge of the conduction band of PbSe, increases the effective mass of charge carriers, and enlarges the energy band gap, which collectively improve the Seebeck coefficient markedly. This is the first example of manipulating the electronic conduction band to enhance the thermoelectric properties of n-type PbSe. Concurrently, Cu2Se increases the carrier concentration with nearly no loss in carrier mobility, even increasing the electrical conductivity above ∼423 K. The resulting power factor is ultrahigh, reaching ∼21–26 μW cm–1 K–2 over a wide range of temperature from ∼423 to 723 K. Cu2Se doping substantially reduces the lattice thermal conductivity to ∼0.4 W m–1 K–1 at 773 K, approaching its theoretical amorphous limit. According to first-principles calculations, the achieved ultralow value can be attributed to remarkable acoustic phonon softening at the low-frequency region.
LB  - PUB:(DE-HGF)16
C6  - pmid:30343568
UR  - <Go to ISI:>//WOS:000451100600051
DO  - DOI:10.1021/jacs.8b10448
UR  - https://juser.fz-juelich.de/record/867957
ER  -