Resonant Bonding, Multiband Thermoelectric Transport, and Native Defects in n-Type BaBiTe_3–xSe_x (x = 0, 0.05, and 0.1)

Abstract

The unique crystal structure of BaBiTe 3 containing Te···Te resonant bonds and its narrow band gap motivated the systematic study of the thermoelectric transport properties of BaBiTe 3-x Se x (x = 0, 0.05 and 0.1) presented here. This study gives insight in the chemical bonding and thermoelectric transport properties of BaBiTe 3 . The study shows that the presence of Te···Te resonant bonds in BaBiTe 3 is best described as a linear combination of interdigitating (Te 1-) 2 side groups and infinite Te n chains. Rietveld X-ray structure refinements and extrinsic defect 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 (~0.2 at 617 K), for which no such contribution was found. The increase in the band offset between the CBM and bands higher in the conduction band with respect to the selenium content is one possible explanation for the absence of multiband effects in the thermoelectric transport properties of BaBiTe 2.9 Se 0.1.

Photovoltaic properties of new solar cell based on ideal cubic NaNbO3 thin films: a combined experimental and density functional theory study

“…This shows the presence of three optical transitions along the Γ – Γ , X – X and R – R directions at 1.62, 2.13 and 3.24 eV, respectively. A similar behavior was observed by Maier et al , 41 and Peng et al 42 The origin of this behavior is related to the existence of Multiple Electron Pockets in the Conduction and Valance Bands. 41…”

High Quality Factor Enabled by Multiscale Phonon Scattering for Enhancing Thermoelectrics in Low-Solubility n-Type PbTe–Cu2Te Alloys

“…In addition to the optimization of carrier concentration, the electronic and phonon transport properties should be rationally manipulated for further enhancing ZT. Usually, at the optimal carrier concentration, the thermoelectric performance depends primarily on the quality factor B = 4.3223 × 10 –6 × μ­( m */ m e ) 1.5 × T 2.5 /κ l , − where μ, m *, and m e are the carrier mobility, the density of states (DOS) effective mass, and the electron mass, respectively. Evidently, a high quality factor requires large DOS effective mass, high mobility, and low lattice thermal conductivity simultaneously.…”

Bonding Hierarchy Gives Rise to High Thermoelectric Performance in Layered Zintl Compound BaAu2P4

“…In this regard, compounds containing weakly bonded Ba atoms tend to exhibit low κ l . , For example, Ba 8 Au 16 P 30 , a clathrate compound, exhibits κ l of 0.18 W/mK at room temperature . BaBiTe 3 , on the other hand, shows multiband electronic transport properties, as well as low κ l (0.28 W/mK at 300 K) because of the heavy Ba atoms. Moreover, electrostatic repulsion between the lone pairs of the cations and anions introduce anharmonicity in the lattice of BaBiTe 3 , which gives rise to enhanced phonon scattering, leading to low κ l . , In another recent work, the metal phosphides have been shown to exhibit good thermoelectric properties …”