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CMOS integration of inkjet-printed graphene for humidity sensing.

Santra S, Hu G, Howe RC, De Luca A, Ali SZ, Udrea F, Gardner JW, Ray SK, Guha PK, Hasan T - Sci Rep (2015)

Bottom Line: The graphene ink is produced via ultrasonic assisted liquid phase exfoliation in isopropyl alcohol (IPA) using polyvinyl pyrrolidone (PVP) polymer as the stabilizer.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Indian Institute of Technology, Kharagpur, 721302, India.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

Optical absorption spectrum of graphene ink.To avoid scattering loss, the dispersion is diluted to 10 vol% for UV-Vis-NIR measurement. The inset is the cuvette containing original graphene dispersion.
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f3: Optical absorption spectrum of graphene ink.To avoid scattering loss, the dispersion is diluted to 10 vol% for UV-Vis-NIR measurement. The inset is the cuvette containing original graphene dispersion.

Mentions: Optical absorption spectroscopy is used to estimate the concentration of the dispersed graphene using the Beer-Lambert law (), where is the graphene concentration (gL−1) and is the distance the light passes through the dispersion (m). and are the absorption (a.u.) and material dependent optical absorption coefficient (Lg−1m−1) at wavelength (nm), respectively. Figure 3 shows the optical absorption spectrum of the dispersion diluted to 10 vol% to avoid scattering losses during absorption measurement55. The inset of Fig. 3 shows a photograph of a cuvette containing the undiluted graphene dispersion. The spectrum is mostly featureless as expected, due to the linear dispersion of Dirac electrons5657. The peak in the UV region is a signature of the van Hove singularity in the graphene density of states58. Using α660 nm = 2460 Lg−1m−1 47, we estimate the concentration of graphene in the undiluted dispersion as 0.40 gL−1. We note that the graphene ink is stable, without forming any visible aggregation over several months.


CMOS integration of inkjet-printed graphene for humidity sensing.

Santra S, Hu G, Howe RC, De Luca A, Ali SZ, Udrea F, Gardner JW, Ray SK, Guha PK, Hasan T - Sci Rep (2015)

Optical absorption spectrum of graphene ink.To avoid scattering loss, the dispersion is diluted to 10 vol% for UV-Vis-NIR measurement. The inset is the cuvette containing original graphene dispersion.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663628&req=5

f3: Optical absorption spectrum of graphene ink.To avoid scattering loss, the dispersion is diluted to 10 vol% for UV-Vis-NIR measurement. The inset is the cuvette containing original graphene dispersion.
Mentions: Optical absorption spectroscopy is used to estimate the concentration of the dispersed graphene using the Beer-Lambert law (), where is the graphene concentration (gL−1) and is the distance the light passes through the dispersion (m). and are the absorption (a.u.) and material dependent optical absorption coefficient (Lg−1m−1) at wavelength (nm), respectively. Figure 3 shows the optical absorption spectrum of the dispersion diluted to 10 vol% to avoid scattering losses during absorption measurement55. The inset of Fig. 3 shows a photograph of a cuvette containing the undiluted graphene dispersion. The spectrum is mostly featureless as expected, due to the linear dispersion of Dirac electrons5657. The peak in the UV region is a signature of the van Hove singularity in the graphene density of states58. Using α660 nm = 2460 Lg−1m−1 47, we estimate the concentration of graphene in the undiluted dispersion as 0.40 gL−1. We note that the graphene ink is stable, without forming any visible aggregation over several months.

Bottom Line: The graphene ink is produced via ultrasonic assisted liquid phase exfoliation in isopropyl alcohol (IPA) using polyvinyl pyrrolidone (PVP) polymer as the stabilizer.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Indian Institute of Technology, Kharagpur, 721302, India.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus