Chemical vapor deposition fabricates metal-organic frameworks for gas sensing

Metal-organic frameworks (MOFs) are a versatile class of materials comprised of metal ions and organic linkers, and are being developed for fields as diverse as gas storage, mechanical filtration, and drug delivery. One promising use for MOFs is in gas sensing, where their large surface areas and highly tunable properties offer both selectivity and sensitivity. MOF-based gas sensors could provide increased protection for individuals working near hazardous chemicals.

One challenge when developing MOFs for gas sensing is fabricating the materials at scale. Most MOFs are deposited using solution approaches such as solvothermal synthesis or inkjet printing, which are incompatible with typical fabrication processes. Akbari et al. detailed an alternative process, fabricating MOFs on microcantilevers using chemical vapor deposition for effective gas sensing.

“The sensors are fabricated by initially depositing a zinc oxide (ZnO) layer on a silicon microcantilever, followed by the conversion of the ZnO layer into a MOF,” said author David Muñoz-Rojas. “Both the deposition of the ZnO layer and the conversion into MOF are done through gas-based approaches, thus being compatible with clean-room processing and conventional microfabrication techniques.”

In tests, their MOF sensors exhibited gas sensitivity more than 80 times higher than ZnO sensors, with a limit of detection three orders of magnitude lower. The authors plan to continue to improve their devices by further tailoring their responses to specific gas species.

“We plan to explore the full potential of MOF-based microcantilever-gas sensors,” said Muñoz-Rojas. “One important question is how we can improve the selectivity of our sensors. Long-term studies to assess mechanical and chemical stability are also needed.”

Source: “Gas phase growth of metal-organic frameworks on microcantilevers for highly sensitive detection of volatile organic compounds,” by Masoud Akbari, Hamza Mouharrar, Chiara Crivello, Martial Defoort, Eihab Abdel-Rahman, Skandar Basrour, Kevin Musselman, and David Muñoz-Rojas, APL Materials (2024). The article can be accessed at https://doi.org/10.1063/5.0206295 .

This paper is part of the Open Framework Materials Collection, learn more here .