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Enargite Cu 3 PS 4 : A Cu–S‐Based Thermoelectric Material with a Wurtzite‐Derivative Structure
Author(s) -
Tanimoto Takuya,
Suekuni Koichiro,
Tanishita Taiki,
Usui Hidetomo,
Tadano Terumasa,
Kamei Taiga,
Saito Hikaru,
Nishiate Hirotaka,
Lee Chul Ho,
Kuroki Kazuhiko,
Ohtaki Michitaka
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202000973
Subject(s) - wurtzite crystal structure , materials science , thermoelectric effect , thermoelectric materials , crystallite , figure of merit , semiconductor , condensed matter physics , valence (chemistry) , dimensionless quantity , crystallography , nanotechnology , thermal conductivity , optoelectronics , metallurgy , thermodynamics , composite material , physics , zinc , chemistry , quantum mechanics
Compound semiconductors derived from ZnS (zincblende and wurtzite) with tetrahedral framework structures have functions for various applications. Examples of such materials include Cu–S‐based materials with zincblende‐derivative structures, which have attracted attention as thermoelectric (TE) materials over the past decade. This study illuminates superior TE performance in polycrystalline samples of enargite Cu 3 P 1− x Ge x S 4 with a wurtzite‐derivative structure. The substitution of Ge for P dopes holes into the top of the valence band composed of Cu‐3d and S‐3p, whereby its multiband characteristic leads to a high TE power factor. Furthermore, a reduction in the grain size to 50–300 nm can effectively decrease phonon mean free paths, leading to low thermal conductivity. These features result in a dimensionless TE figure of merit ZT of 0.5 at 673 K for the x = 0.2 sample. Environmentally benign and low‐cost characteristics of the constituent elements of Cu 3 PS 4 , as well as its high‐performance thermoelectricity, make it a promising candidate for large‐scale TE applications. Furthermore, this finding extends the development field of Cu–S‐based TE materials to those with wurtzite‐derivative structures.