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Semiconducting BiOCuSe Thermoelectrics and Its Metallic Derivative Bi 2 YO 4 Cu 2 Se 2
Author(s) -
Chou TaLei,
Tewari Girish C.,
Chan TingShan,
Hsu YingYa,
Chen JinMing,
Yamauchi Hisao,
Karppinen Maarit
Publication year - 2015
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201500159
Subject(s) - chemistry , selenide , valence (chemistry) , thermoelectric materials , thermoelectric effect , metal , electrical resistivity and conductivity , crystallography , absorption spectroscopy , inorganic chemistry , selenium , thermodynamics , physics , organic chemistry , quantum mechanics , electrical engineering , engineering
ZrCuSiAs‐type mixed‐anion oxychalcogenides and oxypnictides form a massive family of functional materials readily tailored to host diverse transport properties. Here we investigate semiconducting BiOCuSe, which has been considered as a promising candidate for intermediate‐temperature thermoelectric applications, and its intergrowth derivative Bi 2 YO 4 Cu 2 Se 2 , by using X‐ray absorption spectroscopy. Stronger anisotropy and bond covalency are revealed for the latter phase, and in contrast to the simple charge‐balance scenario of [Bi 3+ O 2– ] + [Cu + Se 2– ] – in the former phase, mixed‐valence Cu + /Cu 2+ with a single coordination sphere is seen in the selenide block of Bi 2 YO 4 Cu 2 Se 2 , which gives rise to a metallic electrical conductivity.