Large‐area synthesis of ultra‐thin, flexible, and transparent conductive metal‐organic framework thin‐films via microfluidic‐based solution shearing process

Iminosemiquinone linker-based conductive metal-organic frameworks (c-MOFs) have attracted much attention as next-generation electronic materials due to their high electrical conductivity combined with high porosity. However, the utility of such c-MOFs in high-performance devices has been limited to date by the lack of high-quality MOFs thin-film processing. Herein, we introduce a technique known as Microfluidic-Assisted Solution Shearing combined with Post-synthetic Rapid Crystallization (MASS-PRC) process to generate a high-quality, flexible, and transparent thin-film of Ni3(hexaiminotriphenylene)2 (Ni3(HITP)2) uniformly over a large-area in a high-throughput manner with thickness controllability down to tens of nanometers. The MASS-PRC process utilizes 1) micromixer-embedded blade to simultaneously mix and continuously supply metal-ligand solution towards the drying front during solution shearing to generate an amorphous thin-film, followed by 2) immersion in amine solution for rapid directional crystal growth. As-synthesized c-MOF film had transparency of up to 88.8% and conductivity as high as 37.1 S/cm. High uniformity in conductivity was confirmed over a 3500 mm2 area with an arithmetic mean roughness (Ra) of 4.78 nm. Our flexible thin-film demonstrated the highest level of transparency for Ni3(HITP)2 and the highest hydrogen sulfide (H2S) sensing performance (2085% at 5 ppm) amongst c-MOFs-based H2S sensors, enabling wearable gas sensing applications. This article is protected by copyright. All rights reserved