A2Bi8Se13 (A = Rb, Cs), CsBi3.67Se6, and BaBi2Se4: New Ternary Semiconducting Bismuth Selenides
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- 作者：Lykourgos Iordanidis ; Paul W. Brazis ; Theodora Kyratsi ; John Ireland ; Melissa Lane ; Carl R. Kannewurf ; Wei Chen ; Jeffrey S. Dyck ; Ctirad Uher ; Nishant A. Ghelani ; Tim Hogan ; and Mercouri G. Kanatzidis
- 刊名：Chemistry of Materials
- 出版年：2001
- 出版时间：February 2001
- 年：2001
- 卷：13
- 期：2
- 页码：622 - 633
- 全文大小：227K
- 年卷期：v.13,no.2(February 2001)
- ISSN：1520-5002
文摘
Rb2Bi8Se13 (I), Cs2Bi8Se13 (II), CsBi3.67Se6 (III), and BaBi2Se4 (IV) were synthesized bydirect combination reactions of the A/Se (A = Rb, Cs, Ba) and Bi2Se3 at 
650 
C. Theirstructures were determined by single-crystal X-ray diffraction. Rb2Bi8Se13 and Cs2Bi8Se13are isostructural and crystallize in the monoclinic space group P21/m (No. 11) with a =13.4931(4) Å, b = 4.1558(3) Å, c = 24.876(2) Å, 
= 96.571(4), R1 = 0.0577, and wR2 =0.1159 [I > 2
(I)] for I and a = 13.704(1) Å, b = 4.1532(4) Å, c = 25.008(2) Å, = 96.848(2),R1 = 0.0497, and wR2 = 0.1123 [I > 2(I)] for II. CsBi3.67Se6 crystallizes in the orthorhombicspace group Pnma (No. 62) with a = 23.421(4) Å, b = 4.1877(8) Å, c = 13.710(3) Å, R1 =0.0611, and wR2 = 0.1384 [I > 2(I)]. BaBi2Se4 crystallizes in the hexagonal space groupP63/m (No. 176) with a = 26.157(1) Å, c = 4.3245(3) Å, R1 = 0.0371, and wR2 = 0.0817 [I> 2(I)]. The structure of A2Bi8Se13 features a three-dimensional framework consisting ofwide rectangular NaCl-type infinite rods, running parallel to the b-axis, which are stitchedtogether by CdI2- and Sb2Se3-type fragments. The NaCl-type blocks are aligned parallel toeach other, and between them are rows of alkali metal ions. CsBi3.67Se6 consists of narrowerNaCl-type infinite rods, which share edges. The cesium metal ions reside in the space betweenthese rods. The bismuth sites that connect the NaCl-type rods are partially occupied. The[Bi2Se4]2- framework in BaBi2Se4 contains tunnels running along the c-axis that are occupiedby Ba atoms. All compounds are narrow band-gap semiconductors. Electrical conductivityand thermoelectric power measurements show that I-IV exhibit n-type charge transport.Compounds I and II, however, can also exhibit p-type behavior. The thermal conductivityfor I and IV is low with room-temperature values of ~1.6 W/(m·K) for I and ~1.2 W/(m·K)for IV. The optical band gaps of all compounds range between 0.3 and 0.6 eV.
650 C. Theirstructures were determined by single-crystal X-ray diffraction. Rb2Bi8Se13 and Cs2Bi8Se13are isostructural and crystallize in the monoclinic space group P21/m (No. 11) with a =13.4931(4) Å, b = 4.1558(3) Å, c = 24.876(2) Å, = 96.571(4), R1 = 0.0577, and wR2 =0.1159 [I > 2(I)] for I and a = 13.704(1) Å, b = 4.1532(4) Å, c = 25.008(2) Å, = 96.848(2),R1 = 0.0497, and wR2 = 0.1123 [I > 2(I)] for II. CsBi3.67Se6 crystallizes in the orthorhombicspace group Pnma (No. 62) with a = 23.421(4) Å, b = 4.1877(8) Å, c = 13.710(3) Å, R1 =0.0611, and wR2 = 0.1384 [I > 2(I)]. BaBi2Se4 crystallizes in the hexagonal space groupP63/m (No. 176) with a = 26.157(1) Å, c = 4.3245(3) Å, R1 = 0.0371, and wR2 = 0.0817 [I> 2(I)]. The structure of A2Bi8Se13 features a three-dimensional framework consisting ofwide rectangular NaCl-type infinite rods, running parallel to the b-axis, which are stitchedtogether by CdI2- and Sb2Se3-type fragments. The NaCl-type blocks are aligned parallel toeach other, and between them are rows of alkali metal ions. CsBi3.67Se6 consists of narrowerNaCl-type infinite rods, which share edges. The cesium metal ions reside in the space betweenthese rods. The bismuth sites that connect the NaCl-type rods are partially occupied. The[Bi2Se4]2- framework in BaBi2Se4 contains tunnels running along the c-axis that are occupiedby Ba atoms. All compounds are narrow band-gap semiconductors. Electrical conductivityand thermoelectric power measurements show that I-IV exhibit n-type charge transport.Compounds I and II, however, can also exhibit p-type behavior. The thermal conductivityfor I and IV is low with room-temperature values of ~1.6 W/(m·K) for I and ~1.2 W/(m·K)for IV. The optical band gaps of all compounds range between 0.3 and 0.6 eV.