ChemInform Abstract: Kinetics and Mechanisms of Aggregative Nanocrystal Growth

Wang, Fudong; Richards, Vernal N.; Shields, Shawn P.; Buhro, William E.

doi:10.1002/chin.201409226

Cited by 5 publications

(3 citation statements)

References 1 publication

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“…However, under such drastic reaction conditions, control of the shape of nanocrystals may be lost due to aggregative growth and Ostwald ripening. 23,24 Another challenge is the propensity of Cu nanocrystals to oxidize. As a consequence, in order to synthesize monodisperse Cu nanocrystals in solution, it is necessary to pay attention to the way by which zero valent Cu atoms are generated.…”

Section: Introductionmentioning

confidence: 99%

Shape-Selective Formation of Monodisperse Copper Nanospheres and Nanocubes via Disproportionation Reaction Route and Their Optical Properties

Guo¹,

Chen²,

Cortie

et al. 2014

J. Phys. Chem. C

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Synthesis of stable and monodisperse Cu nanocrystals of controlled morphology has been a long-standing challenge. In this article, we report a facile disproportionation reaction approach for the synthesis of such nanocrystals in organic solvents. Either spherical or cubic shapes can be produced, depending on conditions. The typical Cu nanospheres are single crystals with a size of 23.4±1.5 nm, and can self-assemble into three-dimensional (3D) nanocrystal superlattices with a large scale. By manipulating the chemical additives, monodisperse Cu nanocubes with tailorable sizes have also been obtained. The probable formation mechanism of these Cu nanocrystals is discussed. The narrow size distribution results in strong surface plasmon resonance (SPR) peaks even though the resonance is located in the interband transition region. Double SPR peaks are observed in the extinction spectra for the Cu nanocubes with relative large sizes. Theoretical simulation of the extinction spectra indicates that the SPR band located at longer wavelengths is caused by assembly of Cu nanocubes into more complex structures. The synthesis procedure that we report here is expected to foster systematic investigations on the physical properties and self-assembly of Cu nanocrystals with shape and size singularity for their potential applications in photonic and nanoelectronic devices.

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Section: Introductionmentioning

confidence: 99%

Shape-Selective Formation of Monodisperse Copper Nanospheres and Nanocubes via Disproportionation Reaction Route and Their Optical Properties

Guo¹,

Chen²,

Cortie

et al. 2014

J. Phys. Chem. C

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“…From figure 11(c), we note that increasing the reaction temperature leads to the increase of the sizes of the synthesized perovskite nanocrystals at equilibrium state in contrast to the growth mechanism proposed by LaMer that increasing reaction temperature results in the decrease of the size of nanocrystals [48,49]. Such a trend suggests that there likely exists the Ostwald ripening of the perovskite nanocrystals from the state at high temperature to the equilibrium state at low temperature.…”

Section: Characterization Of Perovskite Nanocrystalsmentioning

confidence: 75%

Growth of perovskite nanocrystals in poly-tetra fluoroethylene based microsystem: on-line and off-line measurements

Zhang¹,

Luan²,

Huang³

et al. 2019

Nanotechnology

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Cesium lead halide perovskite nanocrystals are photoelectric nanomaterials that have potential applications in a variety of areas due to their excellent photoelectric and tunable photo luminescent properties. In this work, we investigate the synergetic effects of reaction temperature, reaction-capillary length and flow rate on the growth kinetics of perovskite nanocrystals in a PTFE-based microsystem and the photoluminescence characteristics of the perovskite nanocrystals both on-line and off-line. The on-line measurement finds that increasing the reaction temperature leads to the increase of the wavelength of the PL emission peak of the synthesized nanocrystals and reduces the average size of the perovskite nanocrystals synthesized in long reaction-capillaries. The intensity of the PL emission peak of the nanocrystals synthesized at different reaction temperatures decreases with the increase of the flow rate. The off-line measurement reveals that increasing the flow rate generally leads to the blueshift of the PL emission peaks and the decrease of the average size of the perovskite nanocrystals synthesized at the reaction temperature of 160 °C in the capillary length of 60 cm. Increasing temperature leads to the increase of the emission wavelength of the perovskite nanocrystals from 560 to 608 nm. The temperature dependence of the average size of the synthesized nanocrystals with the same synthesis conditions at different temperatures can be described by the Arrhenius relationship with an activation energy of 8.54 kJ mol −1 . Five different cross-sections of the synthesized perovskite nanocrystals are observed, including rhombus, hexagon, rectangle, square and quadrangle with three of them being observed for the first time.

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“…Colloidal nanocrystal formation proceeds by a complex combination of chemical and physical kinetic processes; precursor reduction is a chemical reaction, while nucleation is a physical phase transformation. 2 Nanocrystal growth occurs by physical processes, such as aggregation and monomer attachment, [3][4][5][6] chemical processes, such as autocatalytic growth, [7][8] or a combination of both. 9 In particular, effects of nucleation on colloidal nanocrystal formation remain enigmatic 1,[10][11] due to difficulty in quantifying nucleation kinetics.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the Nucleation and Growth Kinetics of Electron Beam Nanochemistry with Liquid Cell Scanning Transmission Electron Microscopy

Wang¹,

Park²,

Woehl

2018

Preprint

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<div>In this article, we report on complex nanochemistry and transport phenomena associated with nanocrystal formation by electron beam induced growth and liquid cell electron microscopy (LCEM). We synthesized silver nanocrystals using scanning transmission electron microscopy (STEM) electron beam induced synthesis and systematically varied the electron dose rate, a parameter solely thought to regulate nanocrystal formation kinetics via the rate of metal precursor reduction. Rationally modifying the solution chemistry with tertiary butanol to scavenge radical oxidizing species established a strongly reducing environment and enabled repeatable LCEM experiments. Interestingly, nanocrystal growth rate decreased with increasing electron dose rate despite the predicted increase in reductant concentration. We present evidence that this counterintuitive trend stems from increased oxidizing radical concentration and radical recombination at high magnifications, which together decrease rate of precursor reduction. Nucleation rate was proportional only to imaging magnification, which we rationalized based on local radical accumulation at high magnification causing increased supersaturation and fast nucleation. Radiation chemistry and reactant diffusion scaling models yielded new scaling laws that quantitatively explained the observed effects of electron dose rate on nucleation and growth kinetics. Finally, we introduce a new reaction kinetic model that enables unraveling nucleation and growth kinetics to probe nucleation kinetics occurring at sub-nanometer length scales, which are typically not accessible with LCEM. Our systematic investigation of nanocrystal formation kinetics with LCEM indicates that the intricacies of radiation chemistry and reactant transport must be accounted for to effectively harness radical scavengers and electron beam induced growth to systematically probe nanocrystal formation kinetics. We expect the empirical trends, scaling laws, and reaction kinetic model presented here will be indispensable tools for in situ electron microscopists and materials chemists alike when designing, analyzing, and interpreting LCEM nanocrystal formation data.</div>

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ChemInform Abstract: Kinetics and Mechanisms of Aggregative Nanocrystal Growth

Abstract: Review: 206 refs.

Cited by 5 publications

References 1 publication

Shape-Selective Formation of Monodisperse Copper Nanospheres and Nanocubes via Disproportionation Reaction Route and Their Optical Properties

Shape-Selective Formation of Monodisperse Copper Nanospheres and Nanocubes via Disproportionation Reaction Route and Their Optical Properties

Growth of perovskite nanocrystals in poly-tetra fluoroethylene based microsystem: on-line and off-line measurements

Quantifying the Nucleation and Growth Kinetics of Electron Beam Nanochemistry with Liquid Cell Scanning Transmission Electron Microscopy

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