Probing the multi-step crystallization dynamics of micelle templated nanoparticles: structural evolution of single crystalline γ-Fe<sub>2</sub>O<sub>3</sub>

Liang, Kunyu; Hui, Lok Shu; Turak, Ayse

doi:10.1039/c9nr00148d

Cited by 28 publications

(39 citation statements)

References 69 publications

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“…3 d), where the O 1 s of Ni 3 FeO x has a strong feature at 529.6 eV ascribed to NiO [ 39 ], which greatly diminished with nitridation. For the mixed metal nitride, there is also evidence of an iron hydroxide phase, at 532.2 eV [ 40 , 41 ]. Figure 3 d shows a pure FeO x phase consisting of γ-Fe 2 O 3 nanoparticles as a reference, showing a similar surface hydroxide phase [ 41 ].…”

Section: Resultsmentioning

confidence: 99%

Mesoporous Ternary Nitrides of Earth-Abundant Metals as Oxygen Evolution Electrocatalyst

et al. 2020

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HIGHLIGHTS• 3D mesoporous Ni 3 FeN was constructed through hard templating and thermal nitridation.• Ni 3 FeN exhibits superior electrochemical performance for OER with a small overpotential of 259 mV to achieve a 10 mA cm −2 .• Ni 3 FeN can also deliver a lower charging voltage and longer lifetime than RuO 2 in a rechargeable Zn-air battery.ABSTRACT As sustainable energy becomes a major concern for modern society, renewable and clean energy systems need highly active, stable, and low-cost catalysts for the oxygen evolution reaction (OER). Mesoporous materials offer an attractive route for generating efficient electrocatalysts with high mass transport capabilities. Herein, we report an efficient hard templating pathway to design and synthesize three-dimensional (3-D) mesoporous ternary nickel iron nitride (Ni 3 FeN). The as-synthesized electrocatalyst shows good OER performance in an alkaline solution with low overpotential (259 mV) and a small Tafel slope (54 mV dec −1 ), giving superior performance to IrO 2 and RuO 2 catalysts. The highly active contact area, the hierarchical porosity, and the synergistic effect of bimetal atoms contributed to the improved electrocatalytic performance toward OER.In a practical rechargeable Zn-air battery, mesoporous Ni 3 FeN is also shown to deliver a lower charging voltage and longer lifetime than RuO 2 . This work opens up a new promising approach to synthesize active OER electrocatalysts for energy-related devices.

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Section: Resultsmentioning

confidence: 99%

Mesoporous Ternary Nitrides of Earth-Abundant Metals as Oxygen Evolution Electrocatalyst

et al. 2020

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“…The reverse micelle deposition (RMD) process requires sustained plasma etching to produce monodisperse nanoparticles with a high degree of two-dimensional order, as shown in Figure 2 . Here, MAPbBr 3 nanoparticles are shown, but RMD is able to produce similar nanoparticle dispersions of a wide variety of materials under similar etching conditions 2 , 6 , 12 , 43 , 44 (see Figure SI-2 for AFM of γ-Fe 2 O 3 nanoparticles produced under similar conditions as MAPbBr 3 ).…”

Section: Resultsmentioning

confidence: 98%

“…Using these micelles as “nanoreactors” allows the formation of highly size controllable nanoparticles, with less than 2% deviation in the average particle diameter. 2 , 6 , 12 , 43 , 44 The other advantage of reverse micelle deposition (RMD) is the control over the 2D dispersion: highly ordered periodic arrays with varying spacing and organization are achieved with the simple tuning of deposition parameters. 10 , 12 To produce RMD nanoparticles, poly(styrene- b -2-vinyl pyridine) (PS- b -P2VP) diblock copolymer reverse micelles are formed in a nonpolar solvent.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 2 a shows a ML of the FeCl 3 -loaded micelles on annealed graphene, showing the expected complexation peaks around 1306, 1440, and 1591 cm –1 (indicated by the dotted vertical lines and the dotted green spectrum for the loaded micelles on Al). 43 As there is only about a 10 cm –1 difference between the Fe-2VP peak and the G peak of graphene, the graphene peak is buried as a shoulder in the spectrum due to the surface enhancement from the Cu substrate of the complexated micelle peaks (see Supporting Information, Figure SI-4 for peak deconvolution). However, the 2D peak from graphene is visible, showing the coexistence of both micelles and graphene after spin coating.…”

Section: Resultsmentioning

confidence: 99%

“…Iron oxide was formed by loading anhydrous FeCl 3 (sublimed grade, >99.9%; Sigma-Aldrich) to the micelles and oxygen plasma etching to form γ-Fe 2 O 3 . 43 The final loaded reverse micelle solution was centrifuged to remove excess, noninfiltrated salt and stirred further to prevent coagulation. The solution was spin-coated onto annealed graphene samples or cleaned substrates for characterization and transfer.…”

Section: Methodsmentioning

confidence: 99%

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Universal Transfer Printing of Micelle-Templated Nanoparticles Using Plasma-Functionalized Graphene

Hui

Munir

Vuong

et al. 2020

ACS Appl. Mater. Interfaces

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Nanostructure incorporation into devices plays a key role in improving performance, yet processes for preparing two-dimensional (2D) arrays of colloidal nanoparticles tend not to be universally applicable, particularly for soft and oxygen-sensitive substrates for organic and perovskite-based electronics. Here, we show a method of transferring reverse micelle-deposited (RMD) nanoparticles (perovskite and metal oxide) on top of an organic layer, using a functionalized graphene carrier layer for transfer printing. As the technique can be applied universally to RMD nanoparticles, we used magnetic (γ-Fe 2 O 3 ) and luminescent (methylammonium lead bromide (MAPbBr 3 )) nanoparticles to validate the transfer-printing methodology. The strong photoluminescence from the MAPbBr 3 under UV illumination and high intrinsic field of the γ-Fe 2 O 3 as measured by magnetic force microscopy (MFM), coupled with Raman measurements of the graphene layer, confirm that all components survive the transfer-printing process with little loss of properties. Such an approach to introducing uniform 2D arrays of nanoparticles onto sensitive substrates opens up new avenues to tune the device interfacial properties.

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Enhanced Stokes Shift and Phase Stability by Cosynthesizing Perovskite Nanoparticles (MAPbI₃/MAPbBr₃) in a Single Solution

Munir

Tan

Arbi

et al. 2022

Advanced Photonics Research

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In recent decades, the family of metal halide hybrid perovskites has attracted attention owing to record-breaking achievements in fields such as photovoltaics (PV), light-emitting diodes (LEDs), lasers, sensors, and many other electronic devices. [1][2][3][4][5][6][7] Perovskites, with the generic chemical formula ABX 3 , owe these properties to their flexible cage crystal structure where the A-site is occupied by a monovalent cation which could either be an organic molecule, such as methylammonium2 ) (FA), or an inorganic atom, such as cesium (Cs þ ); the B-site accommodates a divalent inorganic cation such as lead (Pb 2þ ) or tin (Sn 2þ ); and X position is occupied by a halide group, which could be chloride (Cl À ), bromide (Br À ), or iodide (I À ). [8] A critical issue hindering the commercialization of perovskite-based optoelectronic devices is instability and phase degradation. The desirable α-phase perovskite structure, which is ideal for photoelectric conversion, eventually degrades in ambient conditions into the δ-phase, which is a yellowish nonperovskite phase with an unwanted large bandgap and poor charge transport. [3,[9][10][11][12] Various approaches have been attempted to limit such degradation processes. Common is to use encapsulation approaches, including copolymer micellar shielding, [13][14][15] core-shell formation, [15,16] polymer coprecipitation, [17] solid polymer composite formation, [18][19][20][21] incorporation into metalorganic frameworks (MOFs), [22] or in situ stabilization in mesoporous templates. [23] Another approach is through substitution of suitable ions which stabilize the cage symmetry of optically active perovskites. [6,24,25] Importantly, the substitution of ions also induces changes in the emission and absorption spectrum of the parent composition, resulting in a tunable bandgap by tailoring of the ionic composition. [26] Substitution of halides in particular can be leveraged to tune the emission maxima of the perovskite between 400 ≤ λ ≤ 800 nm. [27][28][29] Therefore, halide substitution offers the best avenue for improving the stability of ABX 3 perovskites, while simultaneously allowing bandgap tunability.

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Probing the multi-step crystallization dynamics of micelle templated nanoparticles: structural evolution of single crystalline γ-Fe₂O₃

Cited by 28 publications

References 69 publications

Mesoporous Ternary Nitrides of Earth-Abundant Metals as Oxygen Evolution Electrocatalyst

Mesoporous Ternary Nitrides of Earth-Abundant Metals as Oxygen Evolution Electrocatalyst

Universal Transfer Printing of Micelle-Templated Nanoparticles Using Plasma-Functionalized Graphene

Enhanced Stokes Shift and Phase Stability by Cosynthesizing Perovskite Nanoparticles (MAPbI₃/MAPbBr₃) in a Single Solution

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Probing the multi-step crystallization dynamics of micelle templated nanoparticles: structural evolution of single crystalline γ-Fe2O3

Cited by 28 publications

References 69 publications

Mesoporous Ternary Nitrides of Earth-Abundant Metals as Oxygen Evolution Electrocatalyst

Mesoporous Ternary Nitrides of Earth-Abundant Metals as Oxygen Evolution Electrocatalyst

Universal Transfer Printing of Micelle-Templated Nanoparticles Using Plasma-Functionalized Graphene

Enhanced Stokes Shift and Phase Stability by Cosynthesizing Perovskite Nanoparticles (MAPbI3/MAPbBr3) in a Single Solution

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Product

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Probing the multi-step crystallization dynamics of micelle templated nanoparticles: structural evolution of single crystalline γ-Fe₂O₃

Enhanced Stokes Shift and Phase Stability by Cosynthesizing Perovskite Nanoparticles (MAPbI₃/MAPbBr₃) in a Single Solution