Metal–Organic Framework Thin Films: Fabrication, Modification, and Patterning

Abstract

Metal–organic frameworks (MOFs) have been of great interest for their outstanding properties, such as large surface area, low density, tunable pore size and functionality, excellent structural flexibility, and good chemical stability. A significant advancement in the preparation of MOF thin films according to the needs of a variety of applications has been achieved in the past decades. Yet there is still high demand in advancing the understanding of the processes to realize more scalable, controllable, and greener synthesis. This review provides a summary of the current progress on the manufacturing of MOF thin films, including the various thin-film deposition processes, the approaches to modify the MOF structure and pore functionality, and the means to prepare patterned MOF thin films. The suitability of different synthesis techniques under various processing environments is analyzed. Finally, we discuss opportunities for future development in the manufacturing of MOF thin films.

Preparation of MOF Film/Aerogel Composite Catalysts via Substrate‐Seeding Secondary‐Growth for the Oxygen Evolution Reaction and CO2 Cycloaddition

“…The thin liquid layer not only provides the required metal precursors and reaction solvent for the MOFs formation, but also serves as a confined space effect in promoting the heterogeneous nucleation of MOFs structures on the substrate, inhibiting the homogeneous nucleation in the liquid phase. [9] In contrast, using soak instead of spray has also been proved to be ineffective to achieve continuous MOFs thin film structure on the aerogel substrate. The soaking process leads full of liquid all over the aerogel, thus no longer existing the confined space effect of thin liquid layer (Figure S10).…”

“…[8] It is noticed that the liquid-phase process would lead to two kinds of competing reaction, including the homogeneous nucleation (the formation of MOFs crystals) in the solvent phase and the heterogeneous reaction (the formation of MOFs films) onto the substrate. [9] It is essential to accelerate the heterogeneous reaction and simultaneously suppress the homogeneous nucleation process in order to achieve the efficient, controllable and green preparation of high-quality MOFs films. Accordingly, a number of fabrication strategies have been developed to prepare substrate-supported MOFs films, such as, layer-bylayer growth, [10] electrochemical synthesis, [11] hot-pressing method, [12] chemical vapor deposition, [13] atomic layer deposition [14] and so on.…”

Infrared crystallography for framework and linker orientation in metal–organic framework films

“…[9][10][11] While MOFs are available in a great variety of shapes, such as nanocrystals, nanospheres, or hierarchical monoliths, MOF thin lms hold tremendous potential to translate the structural properties of individual crystals to continuous, scalable materials. Scalability and processability are essential for the application of MOFs in numerous elds 12,13 such as optics, 9 photonics, 2 catalytic coatings, sensing, solar cells or for batteries. 14 The majority of these applications rely on the precise crystallographic orientation and uniform porosity of the MOF to allow for e.g.…”

Have Covalent Organic Framework Films Revealed Their Full Potential?

“…For example, fully inorganic porous materials provide very good hydro-thermal stability; thus, they are preferred for high-temperature catalytic reactions [5,6]. On the other hand, MOFs have been the most attractive sub-class amongst porous materials [7][8][9][10], from which the highest surface areas were reported until now [11]. The last group, fully organic porous materials, are particularly promising for photocatalysis and electronics due to the easier tunability of their backbone via combining different electron-donating/accepting moieties bearing task-specific functionalities [12,13].…”