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Enhanced Thermoelectric Properties in Cu ‐Doped c‐Axis‐Oriented Ca 3 Co 4 O 9+δ Thin Films
Author(s) -
Wei Renhuai,
Jian Hongbin,
Tang Xianwu,
Yang Jie,
Hu Ling,
Chen Li,
Dai Jianming,
Zhu Xuebin,
Sun Yuping
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12415
Subject(s) - seebeck coefficient , doping , thin film , x ray photoelectron spectroscopy , analytical chemistry (journal) , materials science , thermoelectric effect , electrical resistivity and conductivity , chemistry , nanotechnology , chemical engineering , optoelectronics , electrical engineering , physics , chromatography , engineering , thermodynamics , thermal conductivity , composite material
Highly c‐axis‐oriented Ca 3 Co 4− x Cu x O 9+δ ( x = 0, 0.1, 0.2, and 0.3) thin films were prepared by chemical solution deposition on LaAlO 3 (001) single‐crystal substrates. X‐ray diffraction, field‐emission scanning electronic microscopy, X‐ray photoelectron spectroscopy, and ultraviolet‐visible absorption spectrums were used to characterize the derived thin films. The solubility limit of Cu was found to be less than 0.2, above which [ Ca 2 ( Co 0.65 Cu 0.35 ) 2 O 4 ] 0.624 CoO 2 with quadruplicated rock‐salt layers was observed. The electrical resistivity decreased monotonously with increasing Cu ‐doping content when x ≤ 0.2, and then slightly increased with further Cu doping. The Seebeck coefficient was enhanced from ~100 μV/K for the undoped thin film to ~120 μV/K for the Cu ‐doped thin films. The power factor was enhanced for about two times at room temperature by Cu doping, suggesting that Cu ‐doped Ca 3 Co 4 O 9+δ thin films could be a promising candidate for thermoelectric applications.