Abstract
High thermoelectric performance in oxides requires stable conductive materials that have suitable band structures. Here we show, based on an analysis of the thermopower and related properties using first-principles calculations and Boltzmann transport theory in the relaxation time approximation, that hole-doped Cu2O may be such a material. We find that hole-doped Cu2O has a high thermopower of above 200 μV K−1 even with doping levels as high as 5.2 × 1020 cm−3 at 500 K, mainly attributed to the heavy valence bands of Cu2O. This is reminiscent of the cobaltate family of high-performance oxide thermoelectrics and implies that hole-doped Cu2O could be an excellent thermoelectric material if suitably doped.
Highlights
Thermoelectrics as a field has been attracting increasing attention in recent years
We did convergence tests for the basis set and Brillouin zone sampling. Based on these we used RKmax= 9 (R is the smallest linearized augmented plane-wave (LAPW) sphere radius, i.e. 1.63 bohr and Kmax is the cut-off for the interstitial planewave sector of the basis) with a 12×12×12 k-point mesh for the self-consistent electronic structure calculations
For the transport calculations we employed the electronic structure derived from PBE-generalized gradient approximation (GGA), except that the band gap was corrected to the experimental value using a scissors operator to prevent bipolar transport at high temperature
Summary
Thermoelectrics as a field has been attracting increasing attention in recent years. Thermoelectrics are perhaps the simplest technology for direct thermal to electric energy conversion and can be used in both refrigeration and power generation devices. The efficiency of thermoelectric devices is characterized by a material-dependent figure of merit ZT = S2σT/κ, where T is the temperature, S is the Seebeck coefficient or thermopower, σ is the electrical conductivity, and κ is the thermal conductivity, including both the electronic and lattice contributions. As was emphasized long ago by Ioffe,[1] the carrier concentration needs to be optimized in order to obtain the best balance between thermopower and conductivity in a given semiconductor system. With such optimization, a variety of materials with ZT ~ 1 have been discovered over the years. The state-of-the-art materials, PbTe and PbSe, may be in this latter category.[5, 8,9,10,11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
