A new thermoelectric material Ag8SnS6, with ultra-low thermal conductivity in thin film shape, is prepared on indium tin oxide coated g/ass （ITO） substrates using a chemical process via the electrodeposition techniq...A new thermoelectric material Ag8SnS6, with ultra-low thermal conductivity in thin film shape, is prepared on indium tin oxide coated g/ass （ITO） substrates using a chemical process via the electrodeposition technique. The structural, thermal and electrical properties are studied and presented in detail, which demonstrate that the material is of semiconductor type, orthorhombic structure, with a band gap in the order of 1.56eV and a free carrier concentration of 1.46 × 10^17 cm-3. The thermal conductivity, thermal diffusivity, thermal conduction mode, Seebeck coefficient and electrical conductivity are determined using the photo-thermal deflection technique combined with the Boltzmann transport theory and Cahill＇s model, showing that the AgsSnS6 material has a low thermal conductivity of 3.8 Wm - 1K- 1, high electrical conductivity of 2.4 × 10^5 Sm- 1, Seebeck coefficient of -180μVK-1 and a power factor of 6.9mWK-2m-1, implying that it is more efficient than those obtained in recently experimental investigations for thermoelectric devices.展开更多
Ternary metal chalcogenide semiconductor Ag8 Sn S6, which is an efficient photocatalyst under visible light radiation,is studied by plane-wave pseudopotential density functional theory. After geometry optimization, th...Ternary metal chalcogenide semiconductor Ag8 Sn S6, which is an efficient photocatalyst under visible light radiation,is studied by plane-wave pseudopotential density functional theory. After geometry optimization, the electronic and optical properties are studied. A scissor operator value of 0.81 e V is introduced to overcome the underestimation of the calculation band gaps. The contribution of different bands is analyzed by virtue of total and partial density of states. Furthermore, in order to understand the optical properties of Ag8 Sn S6, the dielectric function, absorption coefficient, and refractive index are also performed in the energy range from 0 to 11 e V. The absorption spectrum indicates that Ag8 Sn S6has a good absorbency in visible light area. Surface energies and work functions of（411）,（4 13）,（21 1）, and（112） orientations have been calculated. These results reveal the reason for an outstanding photocatalytic activity of Ag8 Sn S6.展开更多
基金Supported by the Scientific Research Deanship of University of Dammam under Grant No 2014264
文摘A new thermoelectric material Ag8SnS6, with ultra-low thermal conductivity in thin film shape, is prepared on indium tin oxide coated g/ass （ITO） substrates using a chemical process via the electrodeposition technique. The structural, thermal and electrical properties are studied and presented in detail, which demonstrate that the material is of semiconductor type, orthorhombic structure, with a band gap in the order of 1.56eV and a free carrier concentration of 1.46 × 10^17 cm-3. The thermal conductivity, thermal diffusivity, thermal conduction mode, Seebeck coefficient and electrical conductivity are determined using the photo-thermal deflection technique combined with the Boltzmann transport theory and Cahill＇s model, showing that the AgsSnS6 material has a low thermal conductivity of 3.8 Wm - 1K- 1, high electrical conductivity of 2.4 × 10^5 Sm- 1, Seebeck coefficient of -180μVK-1 and a power factor of 6.9mWK-2m-1, implying that it is more efficient than those obtained in recently experimental investigations for thermoelectric devices.
基金Project supported by the Science and Technology Development Foundation of China(Grant Nos.2012A0302015 and 2012B0302050)
文摘Ternary metal chalcogenide semiconductor Ag8 Sn S6, which is an efficient photocatalyst under visible light radiation,is studied by plane-wave pseudopotential density functional theory. After geometry optimization, the electronic and optical properties are studied. A scissor operator value of 0.81 e V is introduced to overcome the underestimation of the calculation band gaps. The contribution of different bands is analyzed by virtue of total and partial density of states. Furthermore, in order to understand the optical properties of Ag8 Sn S6, the dielectric function, absorption coefficient, and refractive index are also performed in the energy range from 0 to 11 e V. The absorption spectrum indicates that Ag8 Sn S6has a good absorbency in visible light area. Surface energies and work functions of（411）,（4 13）,（21 1）, and（112） orientations have been calculated. These results reveal the reason for an outstanding photocatalytic activity of Ag8 Sn S6.
