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Monodisperse colloidal gallium nanoparticles: synthesis, low temperature crystallization, surface plasmon resonance and Li-ion storage.

Yarema M, Wörle M, Rossell MD, Erni R, Caputo R, Protesescu L, Kravchyk KV, Dirin DN, Lienau K, von Rohr F, Schilling A, Nachtegaal M, Kovalenko MV - J. Am. Chem. Soc. (2014)

Bottom Line: The results point to delta (δ)-Ga polymorph as a single low-temperature phase, while phase transition is characterized by the large hysteresis and by the large undercooling of crystallization and melting points down to 140-145 and 240-250 K, respectively.We have observed size-tunable plasmon resonance in the ultraviolet and visible spectral regions.We also report stable operation of Ga nanoparticles as anode material for Li-ion batteries with storage capacities of 600 mAh g(-1), 50% higher than those achieved for bulk Ga under identical testing conditions.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich , CH-8093 Zürich, Switzerland.

ABSTRACT
We report a facile colloidal synthesis of gallium (Ga) nanoparticles with the mean size tunable in the range of 12-46 nm and with excellent size distribution as small as 7-8%. When stored under ambient conditions, Ga nanoparticles remain stable for months due to the formation of native and passivating Ga-oxide layer (2-3 nm). The mechanism of Ga nanoparticles formation is elucidated using nuclear magnetic resonance spectroscopy and with molecular dynamics simulations. Size-dependent crystallization and melting of Ga nanoparticles in the temperature range of 98-298 K are studied with X-ray powder diffraction, specific heat measurements, transmission electron microscopy, and X-ray absorption spectroscopy. The results point to delta (δ)-Ga polymorph as a single low-temperature phase, while phase transition is characterized by the large hysteresis and by the large undercooling of crystallization and melting points down to 140-145 and 240-250 K, respectively. We have observed size-tunable plasmon resonance in the ultraviolet and visible spectral regions. We also report stable operation of Ga nanoparticles as anode material for Li-ion batteries with storage capacities of 600 mAh g(-1), 50% higher than those achieved for bulk Ga under identical testing conditions.

No MeSH data available.


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Wide-angle powder X-ray diffraction pattern(Cu Kα1 irradiation)for 24 nm Ga NPs at 113 K presented together with theoretical patternfor δ-Ga and a fit obtained by Rietveld refinement. Inset illustratesa crystal structure of δ-Ga polymorph.
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fig3: Wide-angle powder X-ray diffraction pattern(Cu Kα1 irradiation)for 24 nm Ga NPs at 113 K presented together with theoretical patternfor δ-Ga and a fit obtained by Rietveld refinement. Inset illustratesa crystal structure of δ-Ga polymorph.

Mentions: First, we studied the low-temperature crystallization ofcolloidalGa NPs deposited onto an amorphous carbon support using TEM microscopeequipped with a liquid-nitrogen cooled holder. Electron diffractionpatterns, collected upon cooling to 103 K (∼30 min overallcooling time, see also a sequence of diffraction patterns in Movie SI2), provide clear evidence that all studiedsamples with mean sizes of 12.4, 24.0, 32.4, and 44.0 nm were successfullycrystallized (Figures 2B,C and S14). Furthermore, high-resolution images ofcrystalline Ga NPs (Figure 2D) were also acquiredwith clearly resolved lattice fringes from crystalline Ga core, surroundedby an amorphous oxide shell. Low-resolution TEM images of an ensembleof Ga NPs (Figure S12B) illustrate diffractionalcontrast due to random orientation of crystallites. Accurate crystalstructure determination was obtained from XRD patterns collected at113 K, as exemplarily shown for 24 nm Ga NPs in Figure 3. The Rietveld refinement method (FullProf Suite softwarepackage, Figure S15)21 reveals that Ga NPs at T = 113 K existpurely in the δ-Ga modification. The δ-Ga polymorph representsone of the most complex single-component crystal structures, containing66 Ga atoms in the rhombohedral unit cell (R-3m, a = b = 9.087 Å, c = 17.02 Å).22 Most ofGa atoms assemble into hollow icosahedrons, which are interconnectedby joint vertices. In turn, these Ga12 polyhedrons arespaced analogously to the arsenic structure type (Figure 3, inset). The refined lattice parameters are veryclose to those of bulk δ-Ga (a = b = 9.099 Å, c = 17.069 Å). The δ-Gadomain size of 24 nm Ga NPs has been estimated to be ca. 16 nm usingScherrer formula (implemented in Rietveld refinement). This fact staysin a good correspondence with the cryo-TEM measurements (Figure 2D), showing ∼3 nm oxide shell. Importantly,XRD patterns at 113 K and electron diffraction patterns at 103 K canbe indexed to δ-Ga phase for all investigated Ga NPs (from 12to 46 nm). These temperatures are in fact much lower than the knownstability region of bulk δ-Ga polymorph (246–253 K).17a


Monodisperse colloidal gallium nanoparticles: synthesis, low temperature crystallization, surface plasmon resonance and Li-ion storage.

Yarema M, Wörle M, Rossell MD, Erni R, Caputo R, Protesescu L, Kravchyk KV, Dirin DN, Lienau K, von Rohr F, Schilling A, Nachtegaal M, Kovalenko MV - J. Am. Chem. Soc. (2014)

Wide-angle powder X-ray diffraction pattern(Cu Kα1 irradiation)for 24 nm Ga NPs at 113 K presented together with theoretical patternfor δ-Ga and a fit obtained by Rietveld refinement. Inset illustratesa crystal structure of δ-Ga polymorph.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525770&req=5

fig3: Wide-angle powder X-ray diffraction pattern(Cu Kα1 irradiation)for 24 nm Ga NPs at 113 K presented together with theoretical patternfor δ-Ga and a fit obtained by Rietveld refinement. Inset illustratesa crystal structure of δ-Ga polymorph.
Mentions: First, we studied the low-temperature crystallization ofcolloidalGa NPs deposited onto an amorphous carbon support using TEM microscopeequipped with a liquid-nitrogen cooled holder. Electron diffractionpatterns, collected upon cooling to 103 K (∼30 min overallcooling time, see also a sequence of diffraction patterns in Movie SI2), provide clear evidence that all studiedsamples with mean sizes of 12.4, 24.0, 32.4, and 44.0 nm were successfullycrystallized (Figures 2B,C and S14). Furthermore, high-resolution images ofcrystalline Ga NPs (Figure 2D) were also acquiredwith clearly resolved lattice fringes from crystalline Ga core, surroundedby an amorphous oxide shell. Low-resolution TEM images of an ensembleof Ga NPs (Figure S12B) illustrate diffractionalcontrast due to random orientation of crystallites. Accurate crystalstructure determination was obtained from XRD patterns collected at113 K, as exemplarily shown for 24 nm Ga NPs in Figure 3. The Rietveld refinement method (FullProf Suite softwarepackage, Figure S15)21 reveals that Ga NPs at T = 113 K existpurely in the δ-Ga modification. The δ-Ga polymorph representsone of the most complex single-component crystal structures, containing66 Ga atoms in the rhombohedral unit cell (R-3m, a = b = 9.087 Å, c = 17.02 Å).22 Most ofGa atoms assemble into hollow icosahedrons, which are interconnectedby joint vertices. In turn, these Ga12 polyhedrons arespaced analogously to the arsenic structure type (Figure 3, inset). The refined lattice parameters are veryclose to those of bulk δ-Ga (a = b = 9.099 Å, c = 17.069 Å). The δ-Gadomain size of 24 nm Ga NPs has been estimated to be ca. 16 nm usingScherrer formula (implemented in Rietveld refinement). This fact staysin a good correspondence with the cryo-TEM measurements (Figure 2D), showing ∼3 nm oxide shell. Importantly,XRD patterns at 113 K and electron diffraction patterns at 103 K canbe indexed to δ-Ga phase for all investigated Ga NPs (from 12to 46 nm). These temperatures are in fact much lower than the knownstability region of bulk δ-Ga polymorph (246–253 K).17a

Bottom Line: The results point to delta (δ)-Ga polymorph as a single low-temperature phase, while phase transition is characterized by the large hysteresis and by the large undercooling of crystallization and melting points down to 140-145 and 240-250 K, respectively.We have observed size-tunable plasmon resonance in the ultraviolet and visible spectral regions.We also report stable operation of Ga nanoparticles as anode material for Li-ion batteries with storage capacities of 600 mAh g(-1), 50% higher than those achieved for bulk Ga under identical testing conditions.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich , CH-8093 Zürich, Switzerland.

ABSTRACT
We report a facile colloidal synthesis of gallium (Ga) nanoparticles with the mean size tunable in the range of 12-46 nm and with excellent size distribution as small as 7-8%. When stored under ambient conditions, Ga nanoparticles remain stable for months due to the formation of native and passivating Ga-oxide layer (2-3 nm). The mechanism of Ga nanoparticles formation is elucidated using nuclear magnetic resonance spectroscopy and with molecular dynamics simulations. Size-dependent crystallization and melting of Ga nanoparticles in the temperature range of 98-298 K are studied with X-ray powder diffraction, specific heat measurements, transmission electron microscopy, and X-ray absorption spectroscopy. The results point to delta (δ)-Ga polymorph as a single low-temperature phase, while phase transition is characterized by the large hysteresis and by the large undercooling of crystallization and melting points down to 140-145 and 240-250 K, respectively. We have observed size-tunable plasmon resonance in the ultraviolet and visible spectral regions. We also report stable operation of Ga nanoparticles as anode material for Li-ion batteries with storage capacities of 600 mAh g(-1), 50% higher than those achieved for bulk Ga under identical testing conditions.

No MeSH data available.


Related in: MedlinePlus