Biomolecule-assisted hydrothermal synthesis and self-assembly of Bi2Te3 nanostring-cluster hierarchical structure.
A simple biomolecule-assisted hydrothermal approach has been developed for the fabrication of Bi(2)Te(3) thermoelectric nanomaterials. The product has a nanostring-cluster hierarchical structure which is composed of ordered and aligned platelet-like crystals. The platelets are approximately 100 nm in diameter and only approximately 10 nm thick even though a high reaction temperature of 220 degrees C and a long reaction time of 24 h were applied to prepare the sample. The growth of the Bi(2)Te(3) hierarchical structure appears to be a self-assembly process. Initially, Te nanorods are formed using alginic acid as both reductant and template. Subsequently, Bi(2)Te(3) grows in a certain direction on the surface of the Te rods, resulting in the nanostring structure. The nanostrings further recombine side-by-side with each other to achieve the ordered nanostring clusters. The particle size and morphology can be controlled by adjusting the concentration of NaOH, which plays a crucial role on the formation mechanism of Bi(2)Te(3). An even smaller polycrystalline Bi(2)Te(3) superstructure composed of polycrystalline nanorods with some nanoplatelets attached to the nanorods is achieved at lower NaOH concentration. The room temperature thermoelectric properties have been evaluated with an average Seebeck coefficient of -172 microV K(-1), an electrical resistivity of 1.97 x 10(-3) Omegam, and a thermal conductivity of 0.29 W m(-1) K(-1).
Mi
Jian-Li
JL
Department of Chemistry and iNANO, Centre for Materials Crystallography, Aarhus University, Langelandsgade 140, DK-8000 Aarhus, Denmark.
Lock
Nina
N
Sun
Ting
T
Christensen
Mogens
M
Søndergaard
Martin
M
Hald
Peter
P
Hng
Huey H
HH
Ma
Jan
J
Iversen
Bo B
BB
D000464:Alginates / Q000737:chemistry*; D001729:Bismuth / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D055772:Green Chemistry Technology / Q000379:methods*; D006603:Hexuronic Acids / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D019163:Reducing Agents / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry; D013691:Tellurium / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction
D000464:Alginates; D006603:Hexuronic Acids; D019163:Reducing Agents; C542787:bismuth telluride; D012972:Sodium Hydroxide; D020723:Glucuronic Acid; D013691:Tellurium; D001729:Bismuth