Modulating Electrical Conductivity by Activating Open-Metal Sites in Interfacially Grown Coordination Polymer Thin Film

Abstract

Downsizing metal-organic frameworks (MOFs) to thin films and bringing conductivity in such systems is not only beneficial for scientific pursuits but also holds great potential in electronic device applications. Here, we demonstrate, for the first time thin film fabrication of Cu-BTEC using layer-by-layer (LbL) approach resulting in the generation of intrinsic open-metal sites. The as-synthesized film was further doped with a well- known redox-active molecule, TCNQ which is giving rise to a huge conductivity enhancement along with an unheralded rectification ratio (RR) value exceeding five orders of magnitude which remained unchanged at temperatures as high as 450 K. The formation of an electronic heterostructure and not a lattice heterostructure was accounted for this remarkable observation. Additionally, the doping transformed the thin film character from being hydrophilic to highly hydrophobic. Our solution-processable thin film thus appears to be a promising candidate for electronic devices such as diodes and transistors by sustaining high temperatures and being moisture tolerant.