CMOS integration of inkjet-printed graphene for humidity sensing
de, Luca A
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Santra, S., Hu, G., Howe, R., de, L. A., Ali, S., Udrea, F., Gardner, J., et al. (2015). CMOS integration of inkjet-printed graphene for humidity sensing. Scientific Reports, 5 (17374)https://doi.org/10.1038/srep17374
We report on the integration of inkjet-printed graphene with a CMOS micro-electro-mechanical-system (MEMS) microhotplate for humidity sensing. The graphene ink is produced via ultrasonic assisted liquid phase exfoliation in isopropyl alcohol (IPA) using polyvinyl pyrrolidone (PVP) polymer as the stabilizer. We formulate inks with different graphene concentrations, which are then deposited through inkjet printing over predefined interdigitated gold electrodes on a CMOS microhotplate. The graphene flakes form a percolating network to render the resultant graphene-PVP thin film conductive, which varies in presence of humidity due to swelling of the hygroscopic PVP host. When the sensors are exposed to relative humidity ranging from 10–80%, we observe significant changes in resistance with increasing sensitivity from the amount of graphene in the inks. Our sensors show excellent repeatability and stability, over a period of several weeks. The location specific deposition of functional graphene ink onto a low cost CMOS platform has the potential for high volume, economic manufacturing and application as a new generation of miniature, low power humidity sensors for the internet of things.
S.S. acknowledges Department of Science and Technology (DST), India for Ramanujan Fellowship to support the work (project no. SR/S2/RJN-104/2011). This work was (partly) supported through the EU FP7 project MSP (611887). T.H. acknowledges support from the Royal Academy of Engineering through a fellowship (Graphlex).
EC FP7 CP (611887)
External DOI: https://doi.org/10.1038/srep17374
This record's URL: https://www.repository.cam.ac.uk/handle/1810/252560
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Licence URL: http://creativecommons.org/licenses/by/4.0/