A prediction of figure of merit ZT and efficiency for p-type and n-type FeVSb is made by finding out optimal carrier concentration. But, above 500 K the calculated κ ph is in good agreement with experiment. At 300 K, the calculated κ ph is ∼18.6 W m -1 K -1 which is higher compared to experimental value. Using the first-principles anharmonic phonon calculations, the lattice thermal conductivity κ ph of FeVSb is obtained under single-mode relaxation time approximation considering the phonon-phonon interaction. Under quasi-harmonic approximation, the thermal expansion behaviour up to 1200 K is calculated. The effect of long range Coulomb interactions on phonon frequencies are also included by nonanalytical term correction. Further, we study and report the phonon dispersion, density of states and thermodynamic properties. This is supported by the obtained mBJ band gap of ∼0.7 eV. The good agreement between the experimental and calculated S suggests the band gap could be ∼0.7 eV. Using the obtained electronic structure and transport calculations we try to address the experimental Seebeck coefficient S of FeVSb samples. This strategy can be extended to a broad range of advanced alloys and compounds for improved properties.In this work, we have studied the electronic structure of a promising thermoelectric half-Heusler FeVSb using FP-LAPW method and SCAN meta-GGA including spin-orbit coupling. Moreover, vanadium substitution in FeNb 0.56V 0.24Ti 0.2Sb significantly promotes the η to ≈11%. Further manipulation on the dislocation defects at the grain boundaries of p-type Nb 0.8Ti 0.2FeSb leads to enhanced maximum power factor of 47 × 10 -4 W m -1 K -2 and the predicted η of ≈7.5%. The more » samples are featured with dense dislocation arrays at the grain boundaries, leading to a minimum κ L of ≈1 W m -1 K -1 at 900 K and one of the highest ZT (≈1) and predicted η (≈11%) for n-type Hf 0.25Zr 0.75NiSn 0.97Sb 0.03. This study reports a bottom-up nanostructure synthesis approach for these HH materials based on the displacement reaction between metal chlorides/bromides and magnesium (or lithium), followed by vacuum-assisted spark plasma sintering process. Despite of the large thermoelectric power factor and decent figure-of-merit ZT (≈1), their broad applications and enhancement on TE performance are limited by the high intrinsic lattice thermal conductivity (κ L) due to insufficiencies of phonon scattering mechanisms, and the fewer powerful strategies associated with the microstructural engineering for HH materials. Half-Heusler (HH) alloys are among the best promising thermoelectric (TE) materials applicable for the middle-to-high temperature power generation. The concept of manipulating the carrier scattering mechanism to improve the mobility should also be applicable to other material systems. Collectively, a figure of merit ( ZT) of ~1.7 is obtained at 773 K in Mg 3.1Co 0.1Sb 1.5Bi 0.49Te 0.01. A simultaneous reduction in thermal conductivity is also achieved. A significant improvement in Hall mobility from ~16 more » to ~81 cm 2∙V -1∙s -1 is obtained, thus leading to a notably enhanced power factor of ~13 μW∙cm -1∙K -2 from ~5 μW∙cm -1∙K -2. In this work, Fe, Co, Hf, and Ta are doped on the Mg site of Mg 3.2Sb 1.5Bi 0.49Te 0.01, where the ionized impurity scattering crosses over to mixed ionized impurity and acoustic phonon scattering. Here, we demonstrate that by manipulating the carrier scattering mechanism in n-type Mg 3Sb 2-based materials, a substantial improvement in carrier mobility, and hence the power factor, can be achieved. In principle, the carrier mobility is governed by the band structure as well as by the carrier scattering mechanism. Solid-State Solar-Thermal Energy Conversion Center (S3TEC) Sponsoring Org.: USDOE Office of Science (SC), Basic Energy Sciences (BES) OSTI Identifier: 1388433 Grant/Contract Number: SC0001299 FG02-09ER46577 Resource Type: Accepted Manuscript Journal Name: Chemistry of Materials Additional Journal Information: Journal Volume: 29 Journal Issue: 2 Related Information: S3TEC partners with Massachusetts Institute of Technology (lead) Boston College Oak Ridge National Laboratory Rensselaer Polytechnic Institute Journal ID: ISSN 0897-4756 Publisher: American Chemical Society (ACS) Country of Publication: United States Language: English Subject: 36 MATERIALS SCIENCE solar (photovoltaic) solar (thermal) solid state lighting phonons thermal conductivity thermoelectric defects mechanical behavior charge transport spin dynamics materials and chemistry by design optics synthesis (novel materials) synthesis (self-assembly) synthesis (scalable processing)Īchieving higher carrier mobility plays a pivotal role for obtaining potentially high thermoelectric performance. Publication Date: Tue Jan 10 00:00: Research Org.: Energy Frontier Research Centers (EFRC) (United States). of Technology (MIT), Cambridge, MA (United States)
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