Synthesis and Characterization of Quaternary Selenide: TMxSn7-xIn10Se22 (TM = Fe, Co, Ru) and Ag3Ge2.57Sb7.35Se15

• Main Author: 陳俊超
• Other Authors: 李積琛
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/62778098209346615223

碩士 === 國立交通大學 === 應用化學系碩博士班 === 100 === The thesis contains two parts. In part (1), four ternary and quaternary selenides TMxSn7-xIn10Se22 (TM = Fe, Co, Ru) were synthesized and the effect of transition metals to the formation of the target structure was studied. The as-synthesize phase is isostructural to Sn5.5In11S22 that crystalized in monoclinic system with space group P2/m(No.10). The crystal structure contains three building units of rhombus (M4-M5 and M6-M7), planar (M8-M9) and dodecahedrons (M1-M3). The oxidation state of Co is +3, which was supported by magnetic susceptibility analysis. Electrical conductivity measurements revealed semiconducting property for all phases. The Seebeck measurement for Ru0.7Sn6.31In9.99Se22 exhibits n-type semiconducting property. Theoretical calculations show narrow band gap and bonding characters of different metals and Se. In part (2), we obtained a new quaternary selenide Ag3Ge2.57Sb7.35Se15, which crystallizes in the monoclinic space group Cm (No.8) with a = 13.5098(10) Å, b = 4.0844(3) Å, c = 26.329(2) Å, β = 104.837(1)°, V = 1404.4(2) Å3, Z = 2, and R = 0.043. The crystal structure contains two slabs that can be classified as the Lillianite homologous series noted as L (10, 1). A phase width was obtained with the help of two isostructural compounds with different compositions and powder X-ray diffraction. The electrical conductivity of pure phase sample shows narrow band gap in the range of 0.51 eV to 0.71 eV.