Epitaxial Growth of Multilayered Metal–Organic Framework Thin Films for Electronic and Photonic Applications

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.