Epitaxial Growth of MOF Thin Film for Modifying the Dielectric Layer in Organic Field-Effect Transistors

Metal–organic framework (MOF) thin films are important in the application of sensors and devices. However, the application of MOF thin films in organic field effect transistors (OFETs) is still a challenge to date. Here, we first use the MOF thin film prepared by a liquid-phase epitaxial (LPE) approach (also called SURMOFs) to modify the SiO₂ dielectric layer in the OFETs. After the semiconductive polymer of PTB7-Th (poly­[4,8-bis­(5-(2-ethylhexyl)­thiophene-2-yl)­benzo­[1,2-b:4,5-b′]­dithiophene-co-3-fluorothieno­[3,4-b]­thiophene-2-carboxylate]) was coated on MOF/SiO₂ and two electrodes on the semiconducting film were deposited sequentially, MOF-based OFETs were fabricated successfully. By controlling the LPE cycles of SURMOF HKUST-1 (also named Cu₃(BTC)₂, BTC = 1,3,5-benzenetricarboxylate), the performance of the HKUST-1/SiO₂-based OFETs showed high charge mobility and low threshold voltage. This first report on the application of MOF thin film in OFETs will offer an effective approach for designing a new kind of materials for the OFET application.