July 19, 2024
CMOF Nanofilm

Researchers Achieve Control over Orientation of cMOF Nanofilms

Scientists from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences and Kyoto University have developed a strategy to control the orientation of conductive metal-organic frameworks (cMOF) nanofilms on substrates. This breakthrough allows for the precise placement of cMOFs in electrical devices, enhancing their potential for use in modern electronics.

cMOFs are highly porous materials that can conduct charges in a regular network, making them ideal for applications in electrical devices. However, their integration into devices requires precise control over their interface with the substrate. This interface chemistry has posed a challenge for researchers, making it difficult to synthesize and characterize high-quality thin films of cMOFs.

The researchers in this study focused on the orientation control of cMOFs on substrates. They discovered that, contrary to expectations, the observed orientation of cMOFs was face-on rather than edge-on. To overcome this challenge, the scientists developed a method to induce a “standing up” configuration of the cMOF core on the substrates.

Using the Langmuir–Blodgett (LB) technique, the researchers applied high surface pressure to force the ligands of cMOFs to adopt an upright orientation on hydrophilic surfaces. By employing ultra-high concentration and vigorous evaporation during spraying, they were able to create a unique local high surface pressure that induced the desired “standing up” configuration of the ligands. This approach allowed for the fabrication of both “face-on” and “edge-on” thin films of cMOFs.

To verify the crystallinity and orientation of the nanofilms, various reliable analyses were performed. The researchers used atomic force microscopy and X-ray techniques to characterize the films with ultra-thin thicknesses ranging from a few nanometers to tens of nanometers.

The operando characterization methodology using atomic force microscopy and X-ray imaging revealed that the cMOF nanofilms exhibited unique conductive properties. The researchers discovered that the structural softness of the films, in addition to redox interactions, played a significant role in modulating electrical conductivity in an anisotropic way.

This study provides a novel method for achieving control over the orientation of cMOF nanofilms on substrates, which is crucial for their integration into electrical devices. With further research, this breakthrough could pave the way for advancements in the development of high-quality thin films of cMOFs for use in various electronic applications.

1. Source: Coherent Market Insights, Public sources, Desk research
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