Enhanced thermoelectric performance of a chalcopyrite compound CuIn(3)Se(5−x)Te(x) (x = 0~0.5) through crystal structure engineering

In this work the chalcopyrite CuIn(3)Se(5−x)Te(x) (x = 0~0.5) with space group [Image: see text] through isoelectronic substitution of Te for Se have been prepared, and the crystal structure dilation has been observed with increasing Te content. This substitution allows the anion position displacement ∆u = 0.25-u to be zero at x ≈ 0.15. However, the material at x = 0.1 (∆u = 0.15 × 10(−3)), which is the critical Te content, presents the best thermoelectric (TE) performance with dimensionless figure of merit ZT = 0.4 at 930 K. As x value increases from 0.1, the quality factor B, which informs about how large a ZT can be expected for any given material, decreases, and the TE performance degrades gradually due to the reduction in n(H) and enhancement in κ(L). Combining with the ZTs from several chalcopyrite compounds, it is believable that the best thermoelectric performance can be achieved at a certain ∆u value (∆u ≠ 0) for a specific space group if their crystal structures can be engineered.