Abstract
Thermoelectric effects and related technologies have attracted a great interest due to 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 Cu 2Se 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 400 K, a three times larger value than for the normal phases. Dynamic structural transformations introduce intensive fluctuations and extreme complexity, which enhance carrier entropy and thus the thermopower, and strongly scatter carriers and phonons as well to make their transports behave critically.
| Original language | English |
|---|---|
| Pages (from-to) | 121-124 |
| Number of pages | 4 |
| Journal | Materials Letters |
| Volume | 93 |
| DOIs | |
| State | Published - 2013 |
Funding
We thank G. Jeffrey Snyder for helpful discussion. This work is in part supported by National Basic Research Program of China (973-program) under Project No. 2013CB632501 ), NSFC Grants ( 51121064 , 11234012 , 51222209 , and 50825205 ) and CAS/SAFEA International Partnership Program for Creative Research Teams. H.W. and M.J.K are supported by IEA under the Implementing Agreement of AMT via DOE Office EERE Vehicle Technology Program. ORNL is managed by UT-Battelle LLC under DOE contract number DE-AC05-00OR22725 . Q.L. acknowledges support from the US DOE under Contract no. DEAC0298CH10886 . C.U. wishes to acknowledge the support of the Center for Solar and Thermal Energy Conversion Research Center funded by the U.S. DOE under Award no. DE-SC00000957 .
Keywords
- Phase transition
- Semiconductor
- Structure fluctuation
- Thermoelectric