elektronika: Metal–organic framework

Evidence: 100 • authority: 72

Metal-organic frameworks (MOFs) are a class of coordination polymers built from metal nodes, discrete metal ions or metal-oxo clusters, commonly described as secondary building units (SBUs), joined by organic ligands to form one-, two-, or three-dimensional, typically porous frameworks. The ligands may be referred to as "struts" or "linkers", such as 1,4-benzenedicarboxylic acid (H2bdc). More formally, a metal–organic framework is a potentially porous extended structure made from metal ions and organic linkers. An extended structure is a structure whose sub-units occur in a constant ratio and are arranged in a repeating pattern. MOFs are a subclass of coordination networks, which is a coord…

Evidence: 42 • authority: 80

Cyclic Structural Transformations from Crystalline to Crystalline to Amorphous Phases and Magnetic Properties of a Mn(II)-Based MetalOrganic Framework

Evidence: 42 • authority: 92

Comparison of Amorphous and Crystalline Ni-MOFs for Environmental Applications.. Amorphous and crystalline nickel-based metal-organic frameworks (Ni-MOFs) were prepared via a one-pot synthesis at room temperature in methanol using 2-methylimidazole as a ligand. The crystallinity was adjusted by varying the solvent volume, yielding an amorphous phase with higher surface area (≈242 m 2 g -1 ) and a crystalline form with reduced porosity (≈22 m 2 g -1 ). Comprehensive structural, morphological, and spectroscopic analyses confirmed distinct coordination environments, particle sizes and colloidal behaviors. Gas sorption measurements revealed enhanced CO 2 uptake in the amorphous Ni-MOF (≈9.5 cm…

Evidence: 42 • authority: 92

Operando-Defined Amorphous Energy Materials for Electrochemical Energy Systems: From Structural Definition to Descriptor-Guided Design.. Amorphous materials offer distinctive opportunities for electrochemical energy conversion and storage because their local coordination, structural flexibility and metastability can promote catalysis, ion transport and charge storage. However, amorphousness is often inferred only from broad diffraction features or missing lattice fringes, which cannot distinguish genuine amorphous phases from poorly crystalline, defect-rich, surface-amorphized or reconstructed structures. This review establishes an operando-defined framework for understanding and designing…

Evidence: 42 • authority: 72

Thin-film solar cells are a type of solar cell made by depositing thin layers of photovoltaic material onto a glass, plastic or metal substrate. Thin-film solar cells are typically much thinner than the wafers used in conventional crystalline silicon based solar cells. Thin-film solar cells are commercially made with one of several materials including cadmium telluride (CdTe), copper indium gallium diselenide (CIGS), and amorphous thin-film silicon (a-Si, TF-Si). Solar cells are often classified into generations based on the kinds of light-absorbing layers used to make them. The most well-established or first-generation solar cells are made of single- or multi-crystalline silicon. This is t…

Evidence: 42 • authority: 72

The word metalloid comes from the Latin metallum ("metal") and the Greek oeidḗs ("resembling in form or appearance"). However, there is no standard definition of a metalloid and no complete agreement on which elements are metalloids. Despite the lack of specificity, the term remains in use in the literature. The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium and astatine. On a standard periodic table, all eleven elements are in a diagonal region of the p-block extending from boron at the upper left to astatine at lower right. Some periodic tables include…

Evidence: — • authority: 72

Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid (the absorbate) is dissolved by or permeates a liquid or solid (the absorbent). While adsorption does often precede absorption, which involves the transfer of the absorbate into the volume of the absorbent material, alternatively, adsorption is distinctly a surface phenomenon, wherein the adsorbate does not penetrate through the material surface and into the bulk of the adsorbent. The term sorption encompasses both adsorption and absorption, and desorpt…

Evidence: — • authority: 72

In materials science, a single crystal (or single-crystal solid or monocrystalline solid) is a material in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample, with no grain boundaries. The absence of the defects associated with grain boundaries can give monocrystals unique properties, particularly mechanical, optical and electrical, which can also be anisotropic, depending on the type of crystallographic structure. These properties, in addition to making some gems precious, are industrially used in technological applications, especially in optics and electronics. Because entropic effects favor the presence of some imperfections in the micros…

Evidence: — • authority: 72

Zeolitic imidazolate frameworks (ZIFs) are a class of metal–organic frameworks (MOFs) that are topologically isomorphic with zeolites. ZIFs are composed of tetrahedrally-coordinated transition metal ions (e.g. Fe, Co, Zn) connected by imidazolate linkers. Since the metal-imidazole-metal angle is similar to the 145° Si–O–Si angle in zeolites, ZIFs have zeolite-like topologies. As of 2010, 105 ZIF topologies have been reported in the literature. Due to their robust porosity, resistance to thermal changes, and chemical stability, ZIFs are being investigated for applications such as carbon dioxide capture. ZIF glasses can be synthesized by the melt-quench method, and the first melt-quenched ZIF…

Evidence: — • authority: 80

Decision letter for "Crystalline and Amorphous MOFs Based on an Amphiphilic Cyclic Stereoregular p-Carboxyphenylsiloxane: Synthesis, Structures and Properties"

Evidence: — • authority: 80

Decision letter for "Crystalline and Amorphous MOFs Based on an Amphiphilic Cyclic Stereoregular p-Carboxyphenylsiloxane: Synthesis, Structures and Properties"

Evidence: — • authority: 80

Laser Selective Photoactivation of Amorphous TiO2 Films to Anatase and/or Rutile Crystalline Phases