Results for “Ta(CoTe)2” | Engineering Papers

DOE OSTI2020

Materials Data on Ta(CoTe)2 by Materials Project

Ta(CoTe)2 crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of two Ta(CoTe)2 sheets oriented in the (0, 0, 1) direction. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 10-coordinate geometry to eight Co and two equivalent Te atoms. There are four shorter (2.56 Å) and four longer (2.84 Å) Ta–Co bond lengths. Both Ta–Te bond lengths are 2.87 Å. In the second Ta site, Ta is bonded in a 11-coordinate geometry to eight Co and three Te atoms. There are four shorter (2.64 Å) and four longer (2.71 Å) Ta–Co bond lengths. There are one shorter (2.82 Å) and two longer (3.02 Å) Ta–Te bond lengths. There are four inequivalent Co sites. In the first Co site, Co is bonded in a 10-coordinate geometry to four Ta, three Co, and three Te atoms. There are a spread of Co–Co bond distances ranging from 2.56–2.86 Å. There are a spread of Co–Te bond distances ranging from 2.54–2.62 Å. In the second Co site, Co is bonded in a 10-coordinate geometry to four Ta, three Co, and three Te atoms. There are one shorter (2.60 Å) and one longer (2.84 Å) Co–Co bond lengths. There are a spread of Co–Te bond distances ranging from 2.54–2.62 Å. In the third Co site, Co is bonded in a 10-coordinate geometry to four Ta, three Co, and three Te atoms. There are one shorter (2.56 Å) and one longer (2.60 Å) Co–Co bond lengths. There are a spread of Co–Te bond distances ranging from 2.54–2.62 Å. In the fourth Co site, Co is bonded in a 10-coordinate geometry to four Ta, three Co, and three Te atoms. There are one shorter (2.64 Å) and one longer (2.71 Å) Co–Ta bond lengths. The Co–Co bond length is 2.86 Å. There are a spread of Co–Te bond distances ranging from 2.54–2.62 Å. There are three inequivalent Te sites. In the first Te site, Te is bonded in a 5-coordinate geometry to one Ta and four Co atoms. In the second Te site, Te is bonded in a 6-coordinate geometry to two Ta, two Co, and two equivalent Te atoms. There are one shorter (3.25 Å) and one longer (3.33 Å) Te–Te bond lengths. In the third Te site, Te is bonded in a 4-coordinate geometry to four Co atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Boosting Thermoelectric Performance in Nanocrystalline Ternary Skutterudite Thin Films through Metallic CoTe 2 Integration

Metal–semiconductor nanocomposites have emerged as a viable strategy for concurrently tailoring both thermal and electronic transport properties of established thermoelectric materials, ultimately achieving synergistic performance. In this investigation, a series of nanocomposite thin films were synthesized, embedding metallic cobalt telluride (CoTe 2 ) nanophase within the nanocrystalline ternary skutterudite (Co(Ge 1.22 Sb 0.22 )Te 1.58 or CGST) matrix. Our approach harnessed composition fluctuation-induced phase separation and in situ growth during thermal annealing to seamlessly integrate the metallic phase. The distinctive band structures of both materials have developed an ohmic-type contact characteristic at the interface, which raised carrier density considerably yet negligibly affected the mobility counterpart, leading to a substantial improvement in electrical conductivity. The intricate balance in transport properties is further influenced by the metallic CoTe 2 phase’s role in diminishing lattice thermal conductivity. The presence of the metallic phase instigates enhanced phonon scattering at the interface boundaries. Consequently, a 2-fold enhancement in the thermoelectric figure of merit (zT ~ 1.30) is attained with CGST-7 wt. % CoTe 2 nanocomposite film at 655 K compared to that of pristine CGST.

36 MATERIALS SCIENCE↗