scholarly journals Size-Dependent Properties of Solution-Processable Conductive MOF Nanocrystals

2021 ◽  
Author(s):  
Checkers Marshall ◽  
Liam Twight ◽  
Josh Dvorak ◽  
Alexandra Overland ◽  
Carl Brozek
Keyword(s):  
Colloidal Stability ◽  
Semiconductor Nanocrystals ◽  
Nanoparticle Synthesis ◽  
Device Fabrication ◽  
Host Interactions ◽  
Size Dependent ◽  
Complex Architectures ◽  
Metal Organic ◽  
Solution Processable ◽  
Conductive Thin Films

The diverse optical, magnetic, and electronic behaviors of most colloidal semiconductor nanocrystals emerge from materials with limited structural and elemental compositions. Conductive metal-organic frameworks (MOFs) possess rich compositions with complex architectures, but remain unexplored as nanocrystals, hindering their incorporation into scalable devices. Here, we report the controllable synthesis of conductive MOF nanoparticles based on Fe(1,2,3-trizolate)2. Sizes can be tuned as small as 5.5 nm, ensuring indefinite colloidal stability. These solution-processable MOFs can be analyzed by solution-state spectroscopy and electrochemistry and cast into conductive thin films with excellent uniformity. This unprecedented analysis of MOF materials reveals a strong size-dependence in optical and electronic behavior sensitive to the intrinsic porosity and guest-host interactions of MOFs. These results provide a radical departure from typical MOF characterization, enabling insight into physical properties otherwise impossible with bulk analogs, while offering a roadmap for the future of MOF nanoparticle synthesis and device fabrication.

Grain-Size-Dependent Thermal Transport Properties in Nanocrystalline Yttria-Stabilized Zirconia

2001 ◽  
Vol 703 ◽  
Author(s):  
Ho-Soon Yang ◽  
J.A. Eastman ◽  
L.J. Thompson ◽  
G.-R. Bai
Keyword(s):  
Grain Boundaries ◽  
Thermal Transport ◽  
Chemical Vapor ◽  
Yttria Stabilized Zirconia ◽  
Organic Chemical ◽  
Stabilized Zirconia ◽  
Size Dependent ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

ABSTRACTUnderstanding the role of grain boundaries in controlling heat flow is critical to the success of many envisioned applications of nanocrystalline materials. This study focuses on the effect of grain boundaries on thermal transport behavior in nanocrystalline yttria-stabilized zirconia (YSZ) coatings prepared by metal-organic chemical vapor deposition.

Size-Dependent Valence and Conduction Band-Edge Energies of Semiconductor Nanocrystals

ACS Nano ◽  
2011 ◽  
Vol 5 (7) ◽  
pp. 5888-5902 ◽  
Author(s):  
Jacek Jasieniak ◽  
Marco Califano ◽  
Scott E. Watkins
Keyword(s):  
Conduction Band ◽  
Semiconductor Nanocrystals ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Size Dependent

scholarly journals Mechanochemical Approaches Towards the in Situ Confinement of 5-FU Anti-Cancer Drug Within MIL-100 (Fe) Metal-Organic Framework

2020 ◽  
Author(s):  
Barbara Souza ◽  
Jin-Chong Tan
Keyword(s):  
Drug Release ◽  
Metal Organic Framework ◽  
Cancer Drug ◽  
One Pot ◽  
Host Interactions ◽  
Anti Cancer ◽  
Metal Organic ◽  
Iron Based ◽  
Organic Framework

We report two solvent-free mechanochemical methods to achieve one‑pot encapsulation of anti-cancer drug 5‑Fluorouracil (5‑FU) in the iron-based MIL‑100 metal-organic framework (MOF). We compare the structural and physicochemical properties of drug@MIL‑100 systems derived from <i>in situ </i>manual and vortex grinding, where the former exhibits a slower drug release due to stronger guest-host interactions.

scholarly journals Unraveling the Guest-Induced Switchability in the Metal-Organic Framework DUT-13(Zn)

2021 ◽  
Author(s):  
Bodo Felsner ◽  
Volodymyr Bon ◽  
Jack D. Evans ◽  
Friedrich Schwotzer ◽  
Ronny Grünker ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Conformational Isomerism ◽  
Hysteresis Width ◽  
Size Dependent ◽  
Semiempirical Approach ◽  
Contraction Mechanism ◽  
Metal Organic ◽  
Wide Hysteresis ◽  
Breathing Mechanism

A guest-induced flexibility in the framework DUT-13 was investigated in situ to analyze the breathing mechanism upon physisorption of nitrogen (77 K) and n-butane (273 K). The crystal structure of cp phase, solved from PXRD data using the computation-assisted semiempirical approach, shows two times smaller pore volume, compared to the op phase, which is consistent with the corresponding isotherms. The contraction mechanism is mainly based on the conformational isomerism of the benztb4- linker, which transforms from a staggered conformation in op phase to a more eclipsed in cp phase, leading to the contraction of the larger pore. A nearly complete op → cp → op transition was observed in the case of n-butane adsorption at 273 K, while in case of weakly interacting nitrogen molecules a portion of the sample remains in the op phase in the entire pressure range. Apparently, in case of DUT-13 the contraction is crystallite size-dependent, similarly as in a number of other switchable MOFs, which should be investigated more in detail in the future. Methane adsorption at varying temperatures showed a wide hysteresis at the temperatures between 111 K and 140 K. The hysteresis width decreases until it disappears completely at 170 K leading to a reversible isotherm, typical for rigid frameworks. The fact that breathing is observed in a broader temperature range in comparison to DUT‑49 demonstrates that thermodynamics and kinetics favour the DUT-13 contraction. Linker and hinges in DUT-13 are not stiff enough to support the metastable states required for NGA.

scholarly journals Metal Organic Frame-Upconverting Nanoparticle Assemblies for the FRET Based Sensor Detection of Bisphenol A in High-Salt Foods

2020 ◽  
Vol 8 ◽  
Author(s):  
Zhou Xu ◽  
Lin-wei Zhang ◽  
Ling-li Long ◽  
Shao-hua Zhu ◽  
Mao-long Chen ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Dna Sequences ◽  
Colloidal Stability ◽  
Limit Of Detection ◽  
Energy Drink ◽  
High Salt ◽  
Complementary Dna ◽  
Wavelength Absorption ◽  
Metal Organic ◽  
Bpa Detection

To resolve the occurrence of unfulfillable detection in high-salts foods, we used fluorescence resonant energy transfer (FRET) sensors based on nanoparticle upconversion. In this study, we developed a novel FRET sensor for the detection of bisphenol A (BPA) in high-salt foods. We based this approach on the assembly of aptamer modified upconversion nanoparticles (DNA1-UCNPs) and complementary DNA modified metal organic frames (DNA2-MOFs), which possessed corresponding wavelength absorption. Targeting BPA signal transduction was performed using the BPA aptamer, via competitive recognition between the BPA analyte and complementary DNA sequences in a high-salt solution. Sensor adaption in high-salt samples was attributed to functional hydrophilic groups, modified in the MOFs, and the enhanced colloidal stability of these MOFs. The MOF-UCNP assembly displayed considerable analytical performance in terms of BPA detection, with a linear range of 0.1–100 nM, and a limit of detection (LOD) of 0.02 nM, in a 340 mM NaCl food sample (the energy drink, Gatorade). Thus, this method provides a solid basis for small molecules detection in high-salt foods.

scholarly journals Slight pH Fluctuations in the Gold Nanoparticle Synthesis Process Influence the Performance of the Citrate Reduction Method

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2246 ◽  
Author(s):  
Braulio Contreras-Trigo ◽  
Víctor Díaz-García ◽  
Enrique Guzmán-Gutierrez ◽  
Ignacio Sanhueza ◽  
Pablo Coelho ◽  
...  
Keyword(s):  
Large Scale ◽  
Colloidal Suspension ◽  
Nanoparticle Synthesis ◽  
Trisodium Citrate ◽  
Gold Surface ◽  
Point Of View ◽  
Synthesis Process ◽  
Reaction Yield ◽  
Size Dependent ◽  
Gold Nanoparticle Synthesis

Gold nanoparticles (AuNPs) are currently under intense investigation for biomedical and biotechnology applications, thanks to their ease in preparation, stability, biocompatibility, multiple surface functionalities, and size-dependent optical properties. The most commonly used method for AuNP synthesis in aqueous solution is the reduction of tetrachloroauric acid (HAuCl4) with trisodium citrate. We have observed variations in the pH and in the concentration of the gold colloidal suspension synthesized under standard conditions, verifying a reduction in the reaction yield by around 46% from pH 5.3 (2.4 nM) to pH 4.7 (1.29 nM). Citrate-capped AuNPs were characterized by UV-visible spectroscopy, TEM, EDS, and zeta-potential measurements, revealing a linear correlation between pH and the concentration of the generated AuNPs. This result can be attributed to the adverse effect of protons both on citrate oxidation and on citrate adsorption onto the gold surface, which is required to form the stabilization layer. Overall, this study provides insight into the effect of the pH over the synthesis performance of the method, which would be of particular interest from the point of view of large-scale manufacturing processes.

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