A family of metal-organic frameworks (MOFs) and coordination polymers (CPs) based on dynamic structural elements are of great fundamental and commercial interest addressing modern problems in controlled molecular separation, catalysis and even data processing. Herein, the endurance and fast structural dynamics of such materials at ambient conditions are still a fundamental challenge. Here, we report on the design of a series of Cu-based CPs [Cu(bImB)Cl2](1) and [Cu(bImB)2Cl2] (2), where bImB is 1,4-bis(imidazol-1-yl)butane), with flexible ligand packed into one-and two-dimensional (1D, 2D) structures demonstrating dimensionality mediated
Laser interference patterning on top of a thin film and inside a crystal is a powerful tool today to create the desired patterns for optical data processing. Here, we demonstrate reversible and irreversible laser interference patterning on a metal-organic framework (MOF) thin film through the water desorption and thermal decomposition processes, respectively. The irreversible interference pattern with a period of the strips of up to 5 µm has been realized, and its morphology has been characterized using confocal Raman and reflection spectroscopy as well as atomic force microscopy. We revealed that reducing the distance between the interference maxima from 10.5 to a record of 5 µm for MOFs yields a 10-fold increase in the surface roughness of the irreversible pattern; on the other hand, the reversible laser pattern provides a completely non-destructive effect of variable optical contrast. The experimental results obtained open up prospects for the use of MOF crystals as photosensitive materials in the template drawing of the desired patterns for different application scopes.
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.
Nanomaterials
with tunable optical properties have emerged as active
components for advanced nanophotonic devices. Herein, the fabrication
of hierarchical nanostructures through the integration of various
tunable nanomaterials for diverse applications remains a challenge.
Here, a two-step process consisting of the synthesis of silicon nanoparticles
(Si NPs) via laser ablation followed by plasma-enhanced chemical vapor
deposition of hexagonal-boron-nitride (h-BN) nanowalls has been implemented
to form hierarchical Si@h-BN NPs. Experimental and numerical analyses
confirm that h-BN decoration modulates the color and brightness of
the hierarchical NPs (i.e., shape, intensity, and spectral width of
intrinsic optical resonances). Moreover, the color palette of the
resulting Si@h-BN NPs can be remotely controlled by infrared laser
irradiation. We reveal that this control is related to the modification
of the complex morphology of the hierarchical Si@h-BN NPs through
the mutual influence of Si NP and h-BN on each other. These results
open a way for utilizing hierarchical nanostructures for light manipulation
at the nanometer scale for optical data storage and ink-free coloring.
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