Light-Induced Color Switching of Single Metal–Organic Framework Nanocrystals

Abstract

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.

Reversible and Irreversible Laser Interference Patterning of MOF Thin Films

“…The former occurs for 1 s, with a laser intensity of tens of µW cm −2 (see below), due to laser-induced heating followed by the release of water molecules, as we described recently [26]. This process is characterized by a change in the compound refractive index and absorption coefficient [32], and also requires relatively low laser intensities to be initiated. What is important is that the reversible interference patterning does not have an effect on the inner structure of the MOF; hence, the thin film returns to its initial state after turning off the laser.…”

Synthesis and characterization of ZnBTC-based MOFs: effect of solvents and salt

“…Different functionality, adjustable porosity, mechanical strength and thermal stability can be imparted to the framework by changing its constituent parts [22]. Due to these properties MOF appear as promising materials that can be used for the adsorption/storage and separation of gases, in catalysis, biomedicine, and also for the creation of sensor devices [23][24][25][26]. Of particular interest is the further modification of the structure of MOFs, including their intracrystalline space, to create new properties or optimize existing structural/chemical characteristics [27,28].…”

FeAu mixing for high-temperature control of light scattering at the nanometer scale

“…S16a †), excited with a linearly p-polarized white light at an angle of 65°to the pole axis of the NP. 47 Then, we integrated the scattering light in a 0.7π solid angle corresponding to a 0.42 numerical aperture of the objective (see the ESI †). We also proposed that cubic domains of Au and Fe of 10 nm size formed upon heating, followed by domain wall growth, leading to more pronounced separation of Fe and Au.…”