Conductive Ni₃(HITP)₂ nanofilm with asymmetrical morphology prepared by gas–liquid interface self-assembly for glucose sensing

Ni₃(HITP)₂ (HITP: 2,3,6,7,10,11-hexaiminotriphenylene) is a very typical 2D electrically conductive metal–organic framework (EC-MOF) material with great promising as active materials in electronic devices. Gas–liquid interface self-assembly is a common method of processing free-standing thin films for this EC-MOF. Owing to the different contact environment during growth process, Ni₃(HITP)₂ film prepared by gas–liquid interface method has different morphology for up-side surface exposed to air and down-side surface infiltrated in solution. However, the asymmetrical morphology of Ni₃(HITP)₂ film and its influence on sensing performance have never been implemented. In this work, gas–liquid interface self-assembly method is used to obtain an asymmetrical Ni₃(HITP)₂ nanofilm in surface morphology with a flat up-side surface and an island-like down-side surface. The surface morphology of as-prepared film has a remarkable influence on the glucose sensing property. The island-like structure for down-side surface film exhibits more excellent glucose sensing performance because of its abundant crystal defect which play an important role in enhancing glucose catalytic oxidation capacity.