Zr doped β-rhombohedral boron: Widely variable Seebeck coefficient and structural properties

Abstract

The doping effect of zirconium on the structure, Seebeck coefficient and electrical resistivity of β-rhombohedral B was studied for the metal rich concentration range Zr x B 100-x , 1.88x2.75. Structural studies proved the Zr atoms mainly in E and D voids for the metal rich compositions, and also elucidated the minor Zr occupancies of the N, F and A 1 holes. Seebeck coefficients were effectively shifted within a wide range of positive and negative values by varying the Zr content (p-type: S max ~ +420 µVK-1 at 673 K for x=1.88; n-type: S max ~-670 VK-1 at 473 K for x=2.74). Electrical resistivities generally followed the Mott's relation for the variable-range hopping. Excellent compositional agreement has been observed between structural and thermoelectric properties discontinuities.

Thermal conductivity of PrRh4.8B2, a layered boride compound

“…[1][2][3][4][5][6][7] Regarding properties, many studies have been carried out into the magnetism of borides, [7][8][9][10][11][12][13][14] and recent especial efforts have been made to develop the high temperature thermoelectric properties of novel borides. [15][16][17][18][19][20] Being refractory materials, thermoelectric borides have the potential to be used in high impact energy-saving applications like topping cycles for power plants and waste heat power generation in industry. 21,22 The quality of thermoelectric materials can be expressed by the figure of merit ZT = S 2 T /ρκ, where S, ρ, κ, and T are the Seebeck coefficient, electrical resistivity, thermal conductivity, and temperature, respectively.…”

Boron-phil and boron-phob structure units in novel borides Ni3Zn2B and Ni2ZnB: experiment and first principles calculations

“…[10][11][12] It is worth mentioning that due to the electron deficiency of boron in most cases, only electropositive elements such as rare earth metals can form the so called "higher borides" with three-dimensional boron frameworks. [13][14][15][16][17][18] In this work, we have particularly focused on the four ternary borides (τ 3 , τ 4 , τ 5 , and τ 6 ) which all adhere to the isopleth extending from NiB to NiZn. As bonding defines the physical properties, the DFT studies accompanying the experiment will provide thermodynamic and elastic stability and elucidate the underlying electronic structure in terms of charge transfer, density of states, band structures and charge density distribution.…”

An alternative, faster and simpler method for the formation of hierarchically porous ZnO particles and their thermoelectric performance

“…Some notable examples of oxide-TE materials are Na x Co 2 O 4 and SrTiO 3 . 5,7,[9][10][11] We believe that these oxide-based materials could provide an inexpensive, environmentally-friendly viable high temperature thermoelectric material. The progress in developing n-type oxide TE materials with comparable ZT is still lacking, which calls for more research efforts in this area.…”

“…Furthermore, there are several promising high temperature TE applications 9 which require high temperature stable materials, such as, borides 10 and oxides. Some notable examples of oxide-TE materials are Na x Co 2 O 4 and SrTiO 3 .…”