Polymers with embedded metal–organic frameworks (MOFs) have been of interest in research for advanced applications in gas separation, catalysis and sensing due to their high porosity and chemical selectivity. In this study, we utilize specific MOFs with high thermal stability and non-centrosymmetric crystal structures (zeolitic imidazolate framework, ZIF-8) in order to give an example of MOF–polymer composite applications in nonlinear optics. The synthesized MOF-based polymethyl methacrylate (PMMA) composite (ZIF-8–PMMA) demonstrates the possibility of the visualization of near-infrared laser beams in the research lab. The resulting ZIF-8–PMMA composite is exposed to a laser under extreme conditions and exhibits enhanced operating limits, much higher than that of the widely used inorganic materials in optics. Overall, our findings support the utilization of MOFs for synthesis of functional composites for optical application.
Metal-organic frameworks (MOFs) represent a unique platform for fabrication of nanoparticles (NPs) of diverse composition and crystallinity. The growth of NPs from constituent parts of MOFs is usually initiated by external stimuli such as temperature, light and electron irradiation. Herein, the kinetics and NP growth mechanisms remain unexplored. Here, we utilized electron irradiation to initiate the nucleation and growth of crystalline Cu NPs of tunable size from several nanometers to hundreds of nanometers inside MOF as a precursor. Simultaneously, the process of the NPs growth, captured in real time using transmission electron microscope, demonstrates the evolution of their size, shape and spatial distribution. We also analyze the NP growth by the classical kinetic theory taking into account a phase transformation. Our results contribute to crystal engineering and developing of functional MOF-based nanocomposites.
Photoinduced
modulation of the optical parameters of nanomaterials
underlies the operating principles of all-optical nanodevices. Here,
we demonstrate the laser-induced 10% modulation of the refractive
index and 16-fold modulation of the extinction coefficient of the
dynamic metal–organic framework (HKUST-1) nanocrystals within
the whole visible range. Using the laser-induced water sorption/desorption
process inside HKUST-1, we have achieved size-dependent reversible
tuning of brightness and color of its nanocrystals over the different
spatial directions and color palette. The numerical analysis also
confirmed the detected optical tuning through the evolution of optical
spectra and directivity of the scattered light. The results of the
work demonstrate the promising nature of the dynamic metal–organic
frameworks for nonlinear optics and expand the library of chemically
synthesized hybrid materials with light-controlled optical properties.
Metal‐organic frameworks (MOFs), demonstrating structural response on external stimuli, represent a promising family of crystalline materials for microelectronic and data storage devices. Herein, manipulation with MOF structure at the nanometer scale for the device miniaturization is still a challenge. Here, mechanical recording and reading the nanometer scale patterns onto flexible 2D MOF at ambient conditions are reported. Treatment of the MOF surface with a hot solvent decreases the roughness up to 1/7 of the layer thickness. Therefore, an atomic force microscope probe is allowed to cause the deformations with the spatial resolution up to 25 nm (≈0.1 Tbyte inch−2 storage density) and the depth from 0.4 nm. Selective chemical etching by the solvent can further develop the pattern, while the integrity of the MOF structure maintains. The realization of the "read‐only‐memory" concept on flexible MOF at ambient conditions paves the way for next‐generation sustainable data storage materials.
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