Direct Synthesis of Vertically Oriented π-Conjugated Metal-Organic Frameworks on Conductive Substrates

The π-conjugated metal–organic frameworks (MOFs) are a new class of MOFs with strong in-plane π-conjugation and weak out-of-plane π-π stacking. The π-conjugated MOFs exhibit notable properties such as intrinsic porosity, crystallinity as well as excellent electrical conductivity mediated by delocalized π-electrons. These unique features have motivated increasing effort to explore the π-conjugated MOFs for promising device applications in optoelectronics, catalysis, and energy that require the π-conjugated MOFs in the form of thin film or coating. In this study, vertically aligned triphenylene catecholate-based MOFs were directly grown on conductive substrates by a simple hydrothermal method. Effects of substrate identity such as surface chemistry and roughness on crystal growth behavior such as nucleation density, orientation, and growth kinetics were investigated.