Synthesis and thermal conductivity of type II silicon clathrates

2006 ◽  
Vol 383 (1) ◽  
pp. 111-114 ◽  
Author(s):  
M. Beekman ◽  
G.S. Nolas
Keyword(s):  
Thermal Conductivity ◽  
Type Ii ◽  
Silicon Clathrates

Transport Properties of Type II Sodium-Silicon Clathrates

2005 ◽  
Vol 886 ◽  
Author(s):  
Matt Beekman ◽  
Jan Grkyo ◽  
George S. Nolas
Keyword(s):  
Thermal Conductivity ◽  
Sodium Content ◽  
Type I ◽  
Type Ii ◽  
Conductivity Measurements ◽  
Scanning Calorimetry ◽  
Resistivity Measurements ◽  
Silicon Clathrates ◽  
Covalently Bonded ◽  
First Time

ABSTRACTWe have synthesized the type II silicon clathrates Na1Si136 and Na8Si136, and report on the electrical and thermal transport in these materials. The crystal structure consists of a covalently bonded silicon framework in which sodium guest atoms are encapsulated inside the silicon host framework. Differential scanning calorimetry measurements show the compounds decompose above 600°C to diamond-structure silicon. Temperature dependant electrical resistivity measurements show the specimens to have an insulating character, with magnitudes that decrease with increasing sodium content. For the first time, thermal conductivity measurements on type II sodium-silicon clathrates are presented. The thermal conductivity is very low for both specimens, and for Na8Si136 exhibits a clear dip in the range from 50 to 70 K. These data suggest that the “rattling” behavior observed in type I clathrates may also be present in type II clathrates.

Giant reduction in thermal conductivity of extended type-I silicon clathrates and prominent thermal effect of 6d guest Wyckoff positions

2017 ◽  
Vol 5 (40) ◽  
pp. 10578-10588 ◽  
Author(s):  
Yufei Gao ◽  
Xiaoliang Zhang ◽  
Yanguang Zhou ◽  
Ming Hu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Effect ◽  
High Performance ◽  
Type I ◽  
Silicon Clathrates ◽  
Extended Type ◽  
Reduction Effect

Clathrates exhibit exceptional properties such as high-performance thermoelectrics. The extension of cages and guest atoms in 6d Wyckoff positions (other than 2a positions) both have huge reduction effect on the thermal conductivity of Type-I clathrates, which provides important guidance to exploring new kinds of silicon clathrates for advanced thermoelectrics.

Efficient route to phase selective synthesis of type II silicon clathrates with low sodium occupancy

CrystEngComm ◽  
2014 ◽  
Vol 16 (19) ◽  
pp. 3940-3949 ◽  
Author(s):  
Lakshmi Krishna ◽  
Lauryn L. Baranowski ◽  
Aaron D. Martinez ◽  
Carolyn A. Koh ◽  
P. Craig Taylor ◽  
...  
Keyword(s):  
Selective Synthesis ◽  
Type Ii ◽  
Silicon Clathrates ◽  
Low Sodium ◽  
Efficient Route

Dynamic free energy surfaces for sodium diffusion in type II silicon clathrates

2016 ◽  
Vol 18 (7) ◽  
pp. 5121-5128 ◽  
Author(s):  
J. G. Slingsby ◽  
N. A. Rorrer ◽  
L. Krishna ◽  
E. S. Toberer ◽  
C. A. Koh ◽  
...  
Keyword(s):  
Free Energy ◽  
Wide Band ◽  
Band Gaps ◽  
Type Ii ◽  
Silicon Clathrates ◽  
Photovoltaic Materials ◽  
Earth Abundant ◽  
Energy Surfaces ◽  
Sodium Diffusion

Earth abundant semiconducting type II Si clathrates have attracted attention as photovoltaic materials due to their wide band gaps.

scholarly journals Thermal Conductivity of InAs/GaSb Type II Superlattice

2012 ◽  
Vol 41 (9) ◽  
pp. 2322-2325 ◽  
Author(s):  
Chuanle Zhou ◽  
B. -M. Nguyen ◽  
M. Razeghi ◽  
M. Grayson
Keyword(s):  
Thermal Conductivity ◽  
Type Ii ◽  
Type Ii Superlattice
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