Details

Autor(en) / Beteiligte

• Guo, Kai
• Cao, Qi-Gao
• Feng, Xian-Juan
• Tang, Mei-Bo
• Chen, Hao-Hong
• Guo, Xiangxin
• Chen, Ling
• Grin, Yuri
• Zhao, Jing-Tai

Titel

Enhanced Thermoelectric Figure of Merit of Zintl Phase YbCd2-xMnxSb2 by Chemical Substitution

Ist Teil von

• European Journal of Inorganic Chemistry, 2011, Vol.2011 (26), p.4043-4048

Ort / Verlag

Weinheim: WILEY-VCH Verlag

Erscheinungsjahr

2011

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Samples of Zintl phase YbCd2–xMnxSb2 (CaAl2Si2‐type, space group P$\bar {3}$m1) were prepared by a solid‐state reaction followed by a suitable annealing and spark plasma sintering (SPS) for densification. Investigations were carried out on chemical substitution of Cd by Mn in order to optimize the thermoelectric figure of merit ZT in the solid solution system YbCd2–xMnxSb2 (x = 0, 0.05, 0.1, 0.15, 0.2, 0.4, 0.6, 0.8, 1.0, 1.5 and 2.0). Seebeck coefficients, electrical and thermal conductivities of all the samples were measured in the temperature range 300–650 K. The presence of Mn (x ≤ 0.2) substantially reduces the thermal conductivity and enlarges the Seebeck coefficient, meanwhile decreasing the electrical conductivity to a certain degree. As the concentration of Mn (x) becomes higher than 1.0, the semimetallic nature ofYbCd2–xMnxSb2 changes to that of a semiconductor with the majority the carriers switching from holes to electrons. Of all the samples, polycrystalline YbCd1.85Mn0.15Sb2 (p‐type charge carriers) shows the highest figure of merit ZT of 1.14 at 650 K. The effects of substituting Cd by Mn in Zintl phases YbCd2–xMnxSb2 on their structure and thermoelectric properties are investigated. The presence of Mn reduces the cell parameters and electrical conductivity and enlarges the Seebeck coefficient, but it decreases the thermal conductivity simultaneously. The peak ZT of 1.14 at 650 K can be obtained when x = 0.1.