Structure-fluctuation-induced abnormal thermoelectric properties in semiconductor copper selenide

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Materials Letters

DOI:https://doi.org/10.1016/j.matlet.2012.11.058· OSTI ID:1063151

Liu, Huili ^[1]; Shi, Xun ^[1]; Kirkham, Melanie J ^[2]; Wang, Hsin ^[2]; Li, Qiang ^[3]; Uher, Ctirad ^[4]; Zhang, Wenqing ^[5]; Chen, Lidong ^[1]

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1. Chinese Academy of Sciences
2. ORNL
3. Brookhaven National Laboratory (BNL)
4. University of Michigan
5. Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS)

Thermoelectric effects and related technologies have attracted a great interest due to the world-wide energy harvesting. Thermoelectricity has usually been considered in the context of stable material phases. Here we report that the fluctuation of structures during the second-order phase transition in Cu2Se semiconductor breaks the conventional trends of thermoelectric transports in normal phases, leading to a critically phase-transition-enhanced thermoelectric figure of merit zT above unity at 400K, a three times larger value than for the normal phases. Dynamic structural transformations introduce intensive fluctuations and extreme complexity, which enhance the carrier entropy and thus the thermopower, and strongly scatter carriers and phonons as well to make their transports behave critically.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1063151
• Journal Information: Materials Letters, Vol. 93; ISSN 0167-577X
• Country of Publication: United States
• Language: English

Related Subjects

thermoelectric
structure fluctuation
phase transition
semiconductor