Synthesis and Thermoelectric Properties of the New Ternary Bismuth Sulfides KBi6.33S10 and K2Bi8S13
详细信息 查看全文
- 作者：Mercouri G. Kanatzidis ; Timothy J. McCarthy ; Troy A. Tanzer ; Li-Heng Chen ; Lykourgos Iordanidis ; Tim Hogan ; Carl R. Kannewurf ; Ctirad Uher ; and Baoxing Chen
- 刊名：Chemistry of Materials
- 出版年：1996
- 出版时间：July 1996
- 年：1996
- 卷：8
- 期：7
- 页码：1465 - 1474
- 全文大小：467K
- 年卷期：v.8,no.7(July 1996)
- ISSN：1520-5002
文摘
KBi6.33S10 andK2Bi8S13 were synthesized bythe direct combination of K2S/Bi2S3at hightemperature (>700 
C). The reaction ofK2S/3.3Bi2S3 at 800 C revealedthe presence of anew ternary sulfide KBi6.33S10 (I,92% yield). The shiny, silver polycrystallinematerialcrystallizes in the orthorhombic space group Pnma (No. 62)with a = 24.05(1) Å, b =4.100(2) Å, c = 19.44(1) Å, V = 1917(3)Å3, Z = 4, and dc =5.828 g/cm3. Data withFo2 >3
(Fo2),862; no. of variables 108, 2
max 50. The finalR/Rw = 4.3/4.7%. Thestructure consists ofblocks of Bi2Te3- andCdI2-type units that are connected to form athree-dimensional networkwith K+ ions located in the channels that run along theb axis. The same reaction but witha different reactant ratio at 750 C gave the new ternary sulfideK2Bi8S13 (II, 94%yield).This compound crystallizes in the monoclinic space groupP21/m (No. 11) with a =16.818(2)Å, b = 4.074(5) Å, c = 17.801(3)Å, 
= 90.48(1), V = 1220(2)Å3, Z = 2, and dc =5.900g/cm3. Data with Fo2 >3(Fo2), 1924; no. ofvariables 131, 2max 50. The finalR/Rw =7.3/8.2%. The structure of the shiny rodlike crystals is closelyrelated to that of I. As in I,it also consists of Bi2Te3- andCdI2-type fragments that connect to formK+-filled channels.The two potassium atoms and one bismuth atom are disordered overthree sites. Electricalconductivity on I show semiconducting behavior with102 S/cm at 300 K. Compound IIpossesses an electrical conductivity of 102 S/cm at 300 K.The optical bandgaps of I andII(0.06-0.24 eV) were estimated by infrared diffuse reflectancemeasurements. Thermalanalysis and thermal conductivity data for I andII are reported. The thermal conductivityof KBi6.33S10 is found to be substantiallylower than that of Bi2Te3.
C). The reaction ofK2S/3.3Bi2S3 at 800 C revealedthe presence of anew ternary sulfide KBi6.33S10 (I,92% yield). The shiny, silver polycrystallinematerialcrystallizes in the orthorhombic space group Pnma (No. 62)with a = 24.05(1) Å, b =4.100(2) Å, c = 19.44(1) Å, V = 1917(3)Å3, Z = 4, and dc =5.828 g/cm3. Data withFo2 >3(Fo2),862; no. of variables 108, 2max 50. The finalR/Rw = 4.3/4.7%. Thestructure consists ofblocks of Bi2Te3- andCdI2-type units that are connected to form athree-dimensional networkwith K+ ions located in the channels that run along theb axis. The same reaction but witha different reactant ratio at 750 C gave the new ternary sulfideK2Bi8S13 (II, 94%yield).This compound crystallizes in the monoclinic space groupP21/m (No. 11) with a =16.818(2)Å, b = 4.074(5) Å, c = 17.801(3)Å, = 90.48(1), V = 1220(2)Å3, Z = 2, and dc =5.900g/cm3. Data with Fo2 >3(Fo2), 1924; no. ofvariables 131, 2max 50. The finalR/Rw =7.3/8.2%. The structure of the shiny rodlike crystals is closelyrelated to that of I. As in I,it also consists of Bi2Te3- andCdI2-type fragments that connect to formK+-filled channels.The two potassium atoms and one bismuth atom are disordered overthree sites. Electricalconductivity on I show semiconducting behavior with102 S/cm at 300 K. Compound IIpossesses an electrical conductivity of 102 S/cm at 300 K.The optical bandgaps of I andII(0.06-0.24 eV) were estimated by infrared diffuse reflectancemeasurements. Thermalanalysis and thermal conductivity data for I andII are reported. The thermal conductivityof KBi6.33S10 is found to be substantiallylower than that of Bi2Te3.