Enhancement of thermoelectric properties by Se substitution in layered   bismuth-chalcogenide LaOBiS2-xSex
  We have investigated the thermoelectric properties of the novel layered bismuth chalcogenides LaOBiS2-xSex. The partial substitution of S by Se produced the enhancement of electrical conductivity (metallic characteristics) in LaOBiS2-xSex. The power factor largely increased with increasing Se concentration. The highest power factor was 4.5 uW/cmK2 at around 470 deg. C for LaOBiS1.2Se0.8. The obtained dimensionless figure-of-merit (ZT) was 0.17 at around 470 deg. C in LaOBiS1.2Se0.8. 
Yoshikazu Mizuguchi, Atsushi Omachi, Yosuke Goto, Yoichi Kamihara,   Masanori Matoba, Takafumi Hiroi, Joe Kajitani, Osuke Miura
cond-mat.mtrl-sci cond-mat.supr-con