Enargite Cu3PS4: A Cu–S‐Based Thermoelectric Material with a Wurtzite‐Derivative Structure. (6th April 2020)

• Record Type: Journal Article
• Authors: Tanimoto, Takuya; Suekuni, Koichiro; Tanishita, Taiki; Usui, Hidetomo; Tadano, Terumasa; Kamei, Taiga; Saito, Hikaru; Nishiate, Hirotaka; Lee, Chul Ho; Kuroki, Kazuhiko; Ohtaki, Michitaka
• Is Part Of: Advanced functional materials. Volume 30:Number 22(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-04-06
• Subjects: compound semiconductor -- enargite -- sulfide -- thermoelectrics -- wurtzite; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202000973
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: 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 Cu3 P1− x Ge x S4 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 Cu3 PS4, 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. Abstract : A Cu–S‐based material with a wurtzite‐derivative structure, enargite Cu3 PS4, has high potential as a thermoelectric material. Hole doping by the substitution of Ge for P results in a high power factor and reducing the crystallite size drastically decreases the lattice thermal conductivity. The dimensionless figure of merit, ZT, reaches as high as 0.5 at 673 K for a Ge‐substituted sample.