Toward the integration of metal-organic frameworks (MOFs) for energy storage applications, the thin film formation of two copper-paddlewheel MOF systems (MOF-14 and MOF-399) was investigated. Surface-anchored MOFs (SurMOFs) were fabricated by the sequential, alternating, solution-phase deposition of the inorganic and organic ligand precursors that result in conformal films via a van der Merwe growth mechanism. This is in contrast to most surMOF films that follow a Volmer-Weber growth mechanism with isolated crystallites that nucleate and ripen.  For the surMOF systems within our study, atomic force microscopy imaged a smooth film morphology with surface roughness determined by the underlying substrate. By developing an etch process to selectively remove the film, the physical thickness of the film was characterized by AFM revealing linear film growth as a function of deposition cycles permitting nanometer-resolution control of film thicknesses ranging from 5 to 50 nm.  Electrochemical impedance spectroscopy was used to evaluate the electronic transport properties of the MOF systems. The inherent porosities of the SurMOF films were confirmed by cyclic voltammetry redox probe characterization using ferrocene. The layer-by-layer deposition of these SurMOF systems provides a promising route to incorporate MOFs as thin films with nanoscale thickness control and low surface roughness for electrochemical devices.

Conformal surface-anchored metal-organic frameworks: Characterization of thin film growth, porosity, and electronic transport

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.