Large‐Area Synthesis of Ultrathin, Flexible, and Transparent Conductive Metal–Organic Framework Thin Films via a Microfluidic‐Based Solution Shearing Process

Abstract

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 MOF thin‐film processing. Herein, a technique known as the microfluidic‐assisted solution shearing combined with post‐synthetic rapid crystallization (MASS‐PRC) process is introduced 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) a micromixer‐embedded blade to simultaneously mix and continuously supply the metal–ligand solution toward the drying front during solution shearing to generate an amorphous thin‐film, followed by: 2) immersion in amine solution for rapid directional crystal growth. The as‐synthesized c‐MOF film has transparency of up to 88.8% and conductivity as high as 37.1 S cm−1. The high uniformity in conductivity is confirmed over a 3500 mm2 area with an arithmetic mean roughness (Ra) of 4.78 nm. The flexible thin‐film demonstrates the highest level of transparency for Ni3(HITP)2 and the highest hydrogen sulfide (H2S) sensing performance (2,085% at 5 ppm) among c‐MOFs‐based H2S sensors, enabling wearable gas‐sensing applications.

Surface Atomic Arrangement of Aluminum Ultra-Thin Layers Grown on Si(111)

“…Figure 2 a shows the RHEED pattern of the Al films grown on the Si(111)-7 × 7 surface. The image was captured in the [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ] azimuth direction after 2 h of annealing. The specular beam intensity indicated by spots A and B identifies the Si(111)-1 × 1 lattice originating from the bulk.…”

“…Knowing the details of the surface structure and its crystalline arrangement is critical for the deposition of ultrathin metallic films, especially if protection against atmospheric oxidation is required. The metallic surface is harmed by atmospheric exposure, which causes partial amorphization and severely limits its functionality [ 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. This affects surface electrical conductivity and controls the current efficiency in many applications [ 12 , 13 , 14 ].…”

Application of Metal–Organic Framework in Diagnosis and Treatment of Diabetes

“…Currently, many different synthetic methods can be used to generate MOFs, depending on the framework and property requirements. Commonly used synthesis methods include hydrothermal/solvothermal synthesis [ 16 , 17 , 18 ], room-temperature synthesis, microwave-assisted synthesis [ 19 ], ultrasonic-assisted synthesis [ 20 , 21 ], mechanochemical synthesis [ 22 ], microfluidic synthesis [ 23 , 24 ], biomimetic mineralization [ 25 , 26 ], and so on ( Table 1 ).…”

Assembling Triphenylene-Based Metal–Organic Framework Nanosheets at the Air/Liquid Interface: Modification by Tuning the Spread Solution Concentration

“…Furthermore, the component diversity of MOFs allows increasing both charge density and mobility, resulting in the formation of electrically conductive MOFs. , The rational assembly of ultrathin filmsnanosheetsof conductive MOFs with well-controlled growth direction and film thickness and their integration with other components such as electrodes are critical issues for enabling the use of MOFs in nanotechnological devices such as sensors, transistors, and capacitors . Preparing them into nanosheets not only enables the application of conductive MOFs to elements in electronic devices but also improves their light transparency , and specific surface area, ,, leading to uses in photoelectric conversion devices and enhancement of responsiveness to molecular adsorption in sensing devices. Furthermore, unique properties realized only in the nanosheet state are expected such as topological insulating features and broadened band gaps resulting in semiconductive characteristics. , Ameloot et al .…”