Field-Effect Transistor Based on an in Situ Grown Metal–Organic Framework Film as a Liquid-Gated Sensing Device

Ni₃(HITP)₂, a novel and promising two-dimensional metal-organic framework (MOF) material, has been utilized in the areas of catalysis, sensing, and supercapacitors. It is very suitable for preparing field-effect transistor (FET) devices due to its good conductivity, porous structure, as well as easy film formation. Nevertheless, there is a challenge to transfer membrane materials undamaged to the substrates. Here, we reported a simple approach to fabricate the Ni-MOF-based FET with an in situ grown Ni₃(HITP)₂ membrane as the channel material of the FET. With this method, we obtained a large-area, dense, and uniform film composed of thin sheets, and the thickness and density of the MOF film were tunable through changing the reaction time. The as-prepared Ni-MOF-FET had a good mobility of 45.4 cm² V^-1 s^-1 and on/off current ratio of 2.29 × 10³. Moreover, this FET served as a liquid-gated device for the first time with bipolar behavior and good response to the gluconic acid at the range from 10^-6 to 10^-3 g/mL, verifying the potential of the Ni-MOF-FET as biosensors.