Layer-by-Layer Assembled Conductive Metal-Organic Framework Nanofilms for Room-Temperature Chemiresistive Sensing

The utility of electronically conductive metal-organic frameworks (EC-MOFs) in high-performance devices has been limited to date by a lack of high-quality thin film. The controllable thin-film fabrication of an EC-MOF, Cu3-(HHTP)(2), (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene), by a spray layer-by-layer liquid-phase epitaxial method is reported. The Cu-3(HHTP)(2) thin film can not only be precisely prepared with thickness increment of about 2 nm per growing cycle, but also shows a smooth surface, good crystallinity, and high orientation. The chemiresistor gas sensor based on this high-quality thin film is one of the best room-temperature sensors for NH3 among all reported sensors based on various materials.