Limits...
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

Sensing reproducibility of (a) one sensor during 5 sensing cycles (at 50% RH), (b) long-term stability, and (c) sensing variation of three different identical sensors.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4663628&req=5

f8: Sensing reproducibility of (a) one sensor during 5 sensing cycles (at 50% RH), (b) long-term stability, and (c) sensing variation of three different identical sensors.

Mentions: Reproducibility of a sensor at different sensing cycles and of sensing over a long period are also investigated. We measure response of different sensors with the same design to investigate performance variations between the devices. All the sensors use 0.40 gL−1 ink and are tested at room temperature. The reproducibility of response is demonstrated at 50% for five cycles; Fig. 8(a). The long-term stability of the sensor is investigated over a 4-week period. We do not observe a significant variation (~4%) of response at 30, 40, 50 and 60% during this period; Fig. 8(b). The performance variation is investigated by measuring the response for three separate but identical sensors when exposed to different conditions, with a maximum variation of ~13%; Fig. 8(c). Figure 8(c) also shows a linear response of the sensors. We believe the variation could be further improved by optimizing the sensing layer and graphene flake dimensions for the development of reliable, reproducible, low power and compact sensors.


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)

Sensing reproducibility of (a) one sensor during 5 sensing cycles (at 50% RH), (b) long-term stability, and (c) sensing variation of three different identical sensors.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f8: Sensing reproducibility of (a) one sensor during 5 sensing cycles (at 50% RH), (b) long-term stability, and (c) sensing variation of three different identical sensors.
Mentions: Reproducibility of a sensor at different sensing cycles and of sensing over a long period are also investigated. We measure response of different sensors with the same design to investigate performance variations between the devices. All the sensors use 0.40 gL−1 ink and are tested at room temperature. The reproducibility of response is demonstrated at 50% for five cycles; Fig. 8(a). The long-term stability of the sensor is investigated over a 4-week period. We do not observe a significant variation (~4%) of response at 30, 40, 50 and 60% during this period; Fig. 8(b). The performance variation is investigated by measuring the response for three separate but identical sensors when exposed to different conditions, with a maximum variation of ~13%; Fig. 8(c). Figure 8(c) also shows a linear response of the sensors. We believe the variation could be further improved by optimizing the sensing layer and graphene flake dimensions for the development of reliable, reproducible, low power and compact sensors.

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