Enhancing the thermoelectric performance of a p-type half-Heusler alloy, HfCoSb by incorporation of a band-matched chalcogenide, Cu₂Te

Abstract

Enhancement of figure-of-merit due to band matching and bending at the half-Heusler/chalcogendie interfaces facilitating charge transport while blocking the phonons.

Raman Spectroscopy Study of Phonon Liquid Electron Crystal in Copper Deficient Superionic Thermoelectric Cu2–xTe

“…31 It has been observed that several state of the art TE materials are tellurides, such as PbTe, SnTe, 32,4,5 and Bi 2 Te 3 , 14,15 and have better performances than their Se and S counterparts. 24,25,8 Thus, the present work focuses on the Raman spectroscopic studies of copper tellurides. Like the copper selenides and the sulfides, copper tellurides (CTs) also have an interesting structure, where the tellurium atom forms a rigid sublattice and the liquid-like Cu ions are distributed randomly in the rigid sublattice and thus classified as PLEC.…”

“…The carrier mobility in Cu 2 Te was found to be ∼50−100 cm 2 V −1 s −2 which is greater than those in Cu 2 S (<10 cm 2 V −1 s −2 ) and Cu 2 Se (∼20−40 cm 2 V −1 s −2 ) in the temperature range 50− 300 K. 21 Copper telluride is represented with simple molecular formula Cu 2−x Te, but it shows a quite complex atomic arrangement and forms different phases such as CuTe, Cu 2−x Te, and Cu 2 Te. 33,27,34 The compound has vast technological applications such as solar cells 25,28,6 and fast switches and TE generators; 2,21,26 however, the existence of a variety of polymorphic forms and phases of copper telluride makes understanding of the fundamental properties, such as crystal structure, electronic band structure, phonon dispersion, and phonon−phonon interactions, challenging and thus they remain unexplored. Further, CT also shows a structural phase transition with temperature.…”

“…Recently, superionic Cu 2– x X (X = S, Se) are reported to have ultralow κ and high zT due to the liquid-like behavior of Cu ions around the crystalline sublattice of X and are considered as a new class of phonon–liquid–electron–crystals (PLEC). − ,,− ,,, Further, the superionic CT2 has an interesting structure where the tellurium atom forms a rigid sublattice and the liquid-like Cu ions are distributed randomly in the rigid sublattice and thus classified as PLEC . It has been observed that several state of the art TE materials are tellurides, such as PbTe, SnTe, ,, and Bi 2 Te 3 , , and have better performances than their Se and S counterparts. ,, Thus, the present work focuses on the Raman spectroscopic studies of copper tellurides.…”

Realizing High Thermoelectric Performance of Bi-Sb-Te-Based Printed Films through Grain Interface Modification by an In Situ-Grown β-Cu2-δSe Phase

“…Here, we report a high-performance Bi 0.5 Sb 1.5 Te 3 -based p-type printed material with ZT > 1 using a Cu-Se-based IB without a mechanical pressure treatment. Our work is inspired by the enhanced TE performance observed for a combination of a bulk half-Heusler alloy, HfCoSb, and a band-matched chalcogenide, Cu 2 Te with the same charge carrier polarity, at the interfaces 32 leading to a phonon filtering effect. Similarly, the reason behind using the Cu-Se-based IB instead of previously reported n-type Ag-Sebased ink is that highly conducting bridges of the p-type β-Cu 2-δ Se phase are formed through postprinting sintering via dissociative adsorption of Se by Cu.…”

Phase Transition and Electronic Structures of All-d-Metal Heusler-Type X2MnTi Compounds (X = Pd, Pt, Ag, Au, Cu, and Ni)

“…Heusler compounds naturally have many excellent properties, such as high Curie temperature (T C ) (Wurmehl et al, 2005), adjustable electronic structure, suitable semiconductor lattice constants, and various magnetic properties. Therefore, Heusler compounds can be seen as good candidates for spin gapless semiconductors (SGSs) (Gao and Yao, 2013;Skaftouros et al, 2013;Wang et al, 2016;, thermoelectric materials (Downie et al, 2013;Huang et al, 2018;Mallick and Vitta, 2018), shape memory compounds (SMAs) (Aksoy et al, 2009;Li et al, 2018), half metals (Shigeta et al, 2018;Singh and Gupta, 2019;Hao et al, 2020), and topological insulators (Hou et al, 2015;Lin et al, 2015). Because Heusler compounds possess excellent properties, they have been regarded as a research hot spot over the past 100 years.…”