Ostwald’s Rule of Stages and Its Role in CdSe Quantum Dot Crystallization

Washington, A. L.; Foley, Megan E.; Cheong, Soshan; Quffa, Lieth; Breshike, Christopher J.; Watt, John; Tilley, Richard D.; Strouse, Geoffrey F.

doi:10.1021/ja302964e

Cited by 53 publications

(66 citation statements)

References 37 publications

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“…However, for a variety of materials spanning minerals (1), semiconductors (2), and molecular solids (3), the precipitation of the stable phase is either preceded, or totally replaced, by the formation of metastable polymorphs. Although this general phenomenon has been recognized for nearly a century as Ostwald's Rule of Stages (4), it has lacked thermodynamic justification (5), and so Ostwald's rule has served as more of an empirical heuristic than a predictive law.…”

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confidence: 99%

Nucleation of metastable aragonite CaCO ₃ in seawater

Sun

Jayaraman

Chen

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

225

202

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Predicting the conditions in which a compound adopts a metastable structure when it crystallizes out of solution is an unsolved and fundamental problem in materials synthesis, and one which, if understood and harnessed, could enable the rational design of synthesis pathways toward or away from metastable structures. Crystallization of metastable phases is particularly accessible via low-temperature solution-based routes, such as chimie douce and hydrothermal synthesis, but although the chemistry of the solution plays a crucial role in governing which polymorph forms, how it does so is poorly understood. Here, we demonstrate an ab initio technique to quantify thermodynamic parameters of surfaces and bulks in equilibrium with an aqueous environment, enabling the calculation of nucleation barriers of competing polymorphs as a function of solution chemistry, thereby predicting the solution conditions governing polymorph selection. We apply this approach to resolve the long-standing “calcite–aragonite problem”––the observation that calcium carbonate precipitates as the metastable aragonite polymorph in marine environments, rather than the stable phase calcite––which is of tremendous relevance to biomineralization, carbon sequestration, paleogeochemistry, and the vulnerability of marine life to ocean acidification. We identify a direct relationship between the calcite surface energy and solution Mg–Ca ion concentrations, showing that the calcite nucleation barrier surpasses that of metastable aragonite in solutions with Mg:Ca ratios consistent with modern seawater, allowing aragonite to dominate the kinetics of nucleation. Our ability to quantify how solution parameters distinguish between polymorphs marks an important step toward the ab initio prediction of materials synthesis pathways in solution.

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mentioning

confidence: 99%

Nucleation of metastable aragonite CaCO ₃ in seawater

Sun

Jayaraman

Chen

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

225

202

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“…The structural evolution in the metastable colloidal system agrees well with the classical Ostwald's rule of stages, which were mostly observed in colloids and proteins. Ostwald's rule of stages for quantum dot growth in inorganic crystals such as metal chalcogenide and LiFePO 4 3637, have also been reported, however, rare evidence is available in the growth of elemental NPs. Such an evolution of growth stages indicates that the energy of formation E f , for the observed phases is in the sequence of E f (am) > E f (Ge-III) > E f (Ge-I).…”

Section: Resultsmentioning

confidence: 99%

Spontaneous Growth and Chemical Reduction Ability of Ge Nanoparticles

Liang

Tian

et al. 2013

Sci Rep

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Forming colloidal solutions containing semiconductor quantum-sized nanoparticles (NPs) with clean surface has been a long-standing scientific challenge. In this contribution, we report a “top-down” method for the fabrication of Ge NPs by laser ablation of a Ge target in deionized water without adding any stabilizing reagents. The initial Ge NPs in amorphous structure showed spontaneous growth behavior by aging Ge colloids in deionized water under ambient temperature, which gradually evolved into a metastable tetragonal structure as an intermediate phase and then transformed into the stable cubic structure, being consistent with the Ostwald's rule of stages for the growth in a metastable system. The laser-induced initial Ge NPs demonstrate a unique and prominent size-dependent chemical reductive ability, which is evidenced by the rapid degradation of organic molecules such as chlorinated aromatic compounds, organic dyes, and reduction of heavy metal Cr(VI) ions.

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“…Based on the above variation in peak shape with respect to reaction time, as well as reaction temperature, we can firmly conclude that wurtzite CZGSe is controlled by a kinetic growth process, whereas stannite CZGSe is under thermodynamic control, which could be explained by Ostwald's rule of stages that crystal formation must occur through a series of intermediate crystallographic phases prior to the formation of the final thermodynamically stable structure. [30][31][32][33] Therefore, specific reaction control, such as reaction temperature and time, is crucial for synthesizing CZGSe with a thermodynamically metastable wurtzite structure. Figure 4 a shows a typical TEM image of the as-synthesized CZGSe NCs.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Wurtzite Cu₂ZnGeSe₄ Nanocrystals and their Thermoelectric Properties

Xue

Jiao

Yan

et al. 2013

Chemistry An Asian Journal

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An unusual wurtzite phase of Cu2ZnGeSe4 (CZGSe) has been discovered and its corresponding nanocrystals (NCs) were synthesized by using a facile hot-injection solution-phase synthesis method. Moreover, the formation mechanism of this new phase of CZGSe, instead of the typically observed stannite structure, has been investigated in detail, which indicates that wurtzite CZGSe, which represents the kinetic phase, could be prepared by using a kinetic growth process without phase transformation into the thermodynamically stable stannite structure during the colloidal synthesis. In addition, the potential of wurtzite CZGSe as a thermoelectric material is demonstrated by characterizing the thermoelectric properties of as-synthesized wurtzite CZGSe NCs. This work allows for a rational manipulation of the NCs with a desired crystal structure through adjusting the thermodynamics and kinetics without using any additives and, because of its simplicity and versatility, it may be extended to the phase-controlled synthesis of other chalcogenide NCs.

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Ostwald’s Rule of Stages and Its Role in CdSe Quantum Dot Crystallization

Cited by 53 publications

References 37 publications

Nucleation of metastable aragonite CaCO ₃ in seawater

Nucleation of metastable aragonite CaCO ₃ in seawater

Spontaneous Growth and Chemical Reduction Ability of Ge Nanoparticles

Synthesis of Wurtzite Cu₂ZnGeSe₄ Nanocrystals and their Thermoelectric Properties

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Ostwald’s Rule of Stages and Its Role in CdSe Quantum Dot Crystallization

Cited by 53 publications

References 37 publications

Nucleation of metastable aragonite CaCO 3 in seawater

Nucleation of metastable aragonite CaCO 3 in seawater

Spontaneous Growth and Chemical Reduction Ability of Ge Nanoparticles

Synthesis of Wurtzite Cu2ZnGeSe4 Nanocrystals and their Thermoelectric Properties

Contact Info

Product

Resources

About

Nucleation of metastable aragonite CaCO ₃ in seawater

Nucleation of metastable aragonite CaCO ₃ in seawater

Synthesis of Wurtzite Cu₂ZnGeSe₄ Nanocrystals and their Thermoelectric Properties