The fabrication of oriented, crystalline films of metal-organic frameworks (MOFs) is a critical step toward their application to advanced technologies such as optics, microelectronics, microfluidics and sensing. However, the direct synthesis of MOF films with controlled crystalline orientation remains a significant challenge. Here we report a one-step approach, carried out under mild conditions, that exploits heteroepitaxial growth for the rapid fabrication of oriented polycrystalline MOF films on the centimetre scale. Our methodology employs crystalline copper hydroxide as a substrate and yields MOF films with oriented pore channels on scales that primarily depend on the dimensions of the substrate. To demonstrate that an anisotropic crystalline morphology can translate to a functional property, we assembled a centimetre-scale MOF film in the presence of a dye and showed that the optical response could be switched 'ON' or 'OFF' by simply rotating the film.

The precise alignment of multiple layers of metal–organic framework (MOF) thin films, or MOF‐on‐MOF films, over macroscopic length scales is presented. The MOF‐on‐MOF films are fabricated by epitaxially matching the interface. The first MOF layer (Cu2(BPDC)2, BPDC=biphenyl‐4,4′‐dicarboxylate) is grown on an oriented Cu(OH)2 film by a “one‐pot” approach. Aligned second (Cu2(BDC)2, BDC=benzene 1,4‐dicarboxylate, or Cu2(BPYDC)2, BPYDC=2,2′‐bipyridine‐5,5′‐dicarboxylate) MOF layers can be deposited using liquid‐phase epitaxy. The co‐orientation of the MOF films is confirmed by X‐ray diffraction. Importantly, our strategy allows for the synthesis of aligned MOF films, for example, Cu2(BPYDC)2, that cannot be grown on a Cu(OH)2 surface. We show that aligned MOF films furnished with Ag nanoparticles show a unique anisotropic plasmon resonance. Our MOF‐on‐MOF approach expands the chemistry of heteroepitaxially oriented MOF films and provides a new toolbox for multifunctional porous coatings.

Controlling the direction of molecular-scale pores enables the accommodation of guest molecular-scale species with alignment in the desired direction, allowing for the development of high-performance mechanical, thermal, electronic, photonic and...

Polarization-dependent infrared spectroscopy of oriented metal organic framework films fills the information gap left by diffraction methods and gives access to the orientation of the aromatic linker and initial orientation of ultra-thin films.

The precise alignment of multiple layers of metalorganic framework (MOF) thin films,orMOF-on-MOF films, over macroscopic length scales is presented. The MOF-on-MOF films are fabricated by epitaxially matching the interface. The first MOF layer (Cu 2 (BPDC) 2 ,B PDC = biphenyl-4,4'dicarboxylate) is grown on an oriented Cu(OH) 2 film by a" one-pot" approach. Aligned second (Cu 2 (BDC) 2 ,B DC = benzene1 ,4-dicarboxylate,o rC u 2 (BPYDC) 2 ,B PYDC = 2,2'bipyridine-5,5'-dicarboxylate) MOF layers can be deposited using liquid-phase epitaxy.T he co-orientation of the MOF films is confirmed by X-ray diffraction. Importantly,o ur strategy allows for the synthesis of aligned MOF films,f or example,Cu 2 (BPYDC) 2 ,that cannot be grown on aCu(OH) 2 surface.W es howt hat aligned MOF films furnished with Ag nanoparticles show au nique anisotropic plasmon resonance. Our MOF-on-MOF approach expands the chemistry of heteroepitaxially oriented MOF films and provides an ew toolbox for multifunctional porous coatings.

Multilayered metal–organic frameworks (MOF) thin films, called MOF-on-MOF thin films, generate integrated and multiple functionalities toward high-performance sensing, electrochemical, and optical devices. Although epitaxy at the MOF/MOF interfaces in these multilayered MOF films plays a crucial role for high functionalities, the effect of structural consistency at a molecular scale at the epitaxial interface on the quality of the films (e.g., crystallite size and degree of orientation of MOF-on-MOF thin films) has not been explored. Here, we report the factors governing such physical parameters by revealing a relationship between lattice mismatch ratios and orientations of MOF-on-MOF thin films with epitaxial interfaces (referred as to “e-MoM thin films”). Highly oriented e-MoM thin films were successfully obtained by considering not only lattice mismatch ratios but also stacking order depending on the lattice parameters of MOF components. Because of the chemical and structural tunability of e-MoM materials, the present finding will offer insight into fabricating e-MoM thin films for designing future MOF-based devices.

Metal–organic framework (MOF) coatings were prepared on gold electrodes through the conversion from Cu(OH)2 nanobelts to Cu3(BTC)2 MOFs.

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