Superassembling of Bi₂Te₃hierarchical nanostructures for enhanced thermoelectric performance

Abstract

We describe a facile and one-step pulsed laser deposition (PLD) technique that was first time utilized to systematically fabricate a series of innovative Bi2Te3 superassembly-on-epitaxy bi-layer nanostructures uniquely coupling upper self-assembled well-ordered Bi2Te3 hierarchical nanostructures with unusually high surface-and interface-to-volume ratios and a highly electrical conductive epitaxial bottom thin layer on insulated SiO2/Si substrates as an emerging new class of the most advanced thermoelectric nanomaterials. The optimized power factor of the present superassembly-on-epitaxy films is one to three orders of magnitude higher than that of most Bi2Te3 nanoassemblies defined as assemblies of nanocrystals, evidently proving the significance and potential of the present new concept and resulting thermoelectric nanomaterials.

Design, Performance, and Application of Thermoelectric Nanogenerators

“…V 2 VI 3 ‐ and V 2 VI 3 /IV–VI‐type molecular formulas are typical molecular structures of TE materials, of which the Bi 2 Te 3 series have outstanding TE properties. By controlling temperature and pressure without templates and catalysts, Bi 2 Te 3 nanomaterials with different morphologies can be prepared; their TE properties can be engineered by tuning their nanostructures, including spindle, worm, and island‐like hierarchical nanostructures, as observed in Figure g. Moreover, nanostructuring strategies have been efficiently used in Bi 2 Te 3 ‐based materials to significantly improve the cooling applications based on the Peltier effect near room temperature …”

“…g 1 –g 4 ) SEM images of Bi 2 Te 3 nanomaterials with different morphologies. Reproduced with permission . Copyright 2015, Royal Society of Chemistry.…”

“…In realistic background, TE materials that can directly convert heat into electric energy have become the key research object for scientific researchers. These TE materials or devices show greatly potential applications in waste heat recovery and efficient conversion to electric energy …”

Simultaneously improved electrical properties of crystalline YbAl3 thin films prepared by co-sputtering technique

“…Accordingly, the a 2 s value is signicantly improved at rst with increasing the annealing temperature in the range 723-773 K and then decreases above 773 K. The maximum a 2 s is 7.4 mW m À1 K À2 for the AF773 thin lm, which is much higher than the reported values of other promising TE thin lms. [30][31][32][33][34] Beneting from the high electrical conductivity and large power factor, it's expected that the miniaturized TE devices made by YbAl 3 thin lms have potentially large cooling capacity, large output power, and small Joule heat.…”

Nanostructuring Bi2Te3-Based Thermoelectric Thin-Films Grown Using Pulsed Laser Deposition

“…be KrF excimer laser beam (λ = 248 nm) and Q-switched Nd:YAG laser (λ = 355 nm) with properly selected laser fluence (e.g., 3.8, 6.2, or 8.3 J/cm 2 ) pulsed duration of 5-20 ns, repetition rate of 5-10 Hz [38,[40][41][42]. The laser beam was guided by several UV mirrors and focused on a stoichiometric polycrystalline target (e.g., Bi 2 Se 3 ,Bi 2 Te 3 ,Bi 0.5 Sb 1.5 Te 3 , etc.)…”