The Effect of Thermal Reduction and Film Thickness on fast Response Transparent Graphene Oxide Humidity Sensors

Papamatthaiou, Sotirios; Argyropoulos, D.-P.; Farmakis, Filippos; Masurkar, Arjun V.; Αλεξάνδρου, Κωνσταντίνος; Kymissis, Ioannis; Georgoulas, N.

doi:10.1016/j.proeng.2016.11.201

Cited by 15 publications

(17 citation statements)

References 2 publications

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“…14 Moreover, their sensing performances are often characterized by slow response and recovery times. 13,15,16 Furthermore, because of the poor conductivity of GO (often below 1 × 10 −4 S/m), 17 high potentials need to be applied to reach readable currents, thus resulting in increased power consumption. 18,19 To T h i s c o n t e n t i s overcome the poor conductivity of GO, electrochemical impedance spectroscopy (EIS), which requires a complex and expensive analyzing device, is also employed.…”

Section: ■ Introductionmentioning

confidence: 99%

“…However, since the interactions between the water molecules and the aforementioned functional groups of GO are rather strong, GO-based humidity sensors suffer from large hysteresis and incoherent behavior over time . Moreover, their sensing performances are often characterized by slow response and recovery times. ,, Furthermore, because of the poor conductivity of GO (often below 1 × 10 –4 S/m), high potentials need to be applied to reach readable currents, thus resulting in increased power consumption. , To overcome the poor conductivity of GO, electrochemical impedance spectroscopy (EIS), which requires a complex and expensive analyzing device, is also employed . On the other hand, rGO is 6–7 orders of magnitude more conductive than GO, allowing the fabrication of power-efficient devices .…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast and Highly Sensitive Chemically Functionalized Graphene Oxide-Based Humidity Sensors: Harnessing Device Performances via the Supramolecular Approach

Anichini

Aliprandi

Gali

et al. 2020

ACS Appl. Mater. Interfaces

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Humidity sensors are gaining increasing attention because of their relevance for well-being. To meet the evergrowing demand for new cost-efficient materials with superior performances, graphene oxide (GO) based relative humidity sensors have emerged recently as low-cost and highly sensitive devices. However, current GO-based sensors suffer from important drawbacks including slow response and recovery, as well as poor stability. Interestingly, reduced GO (rGO) exhibits higher stability, yet accompanied by a lower sensitivity to humidity due to its hydrophobic nature. With the aim of improving the sensing performances of rGO, here we report on a novel generation of humidity sensors based on a simple chemical modification of rGO with hydrophilic moieties, i.e. tetraethylene glycol chains. Such hybrid material exhibits an outstandingly improved sensing performance compared to pristine rGO such as high sensitivity (31 % increase in electrical resistance when humidity is shifted from 2 to 97%), an ultrafast response (25 ms) and recovery in the sub-second timescale, low hysteresis (1.1 %), excellent repeatability and stability as well as high selectivity towards moisture. Such highest key performance indicators demonstrate the full potential of 2D materials when decorated suitably designed supramolecular receptors to develop the next generation of chemical sensors of any analyte of interest.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultrafast and Highly Sensitive Chemically Functionalized Graphene Oxide-Based Humidity Sensors: Harnessing Device Performances via the Supramolecular Approach

Anichini

Aliprandi

Gali

et al. 2020

ACS Appl. Mater. Interfaces

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“…Emerging composite and nanomaterials such as ZnO and Pd-SnO 2 also suffer from the same debilitating disadvantage [7,8]. More recently, graphene and graphene oxide have emerged as a promising material for fast humidity sensing, with response times ranging from 10's of milliseconds to a few seconds, depending on the method of production [9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Ultrafast humidity sensor based on liquid phase exfoliated graphene

et al. 2020

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Humidity sensing is important to a variety of technologies and industries, ranging from environmental and industrial monitoring to medical applications. Although humidity sensors abound, few available solutions are thin, transparent, compatible with large-area sensor production and flexible, and almost none are fast enough to perform human respiration monitoring through breath detection or real-time finger proximity monitoring via skin humidity sensing. This work describes chemiresistive graphene-based humidity sensors produced in few steps with facile liquid phase exfoliation followed by Langmuir–Blodgett assembly that enables active areas of practically any size. The graphene sensors provide a unique mix of performance parameters, exhibiting resistance changes up to 10% with varying humidity, linear performance over relative humidity (RH) levels between 8% and 95%, weak response to other constituents of air, flexibility, transparency of nearly 80%, and response times of 30 ms. The fast response to humidity is shown to be useful for respiration monitoring and real-time finger proximity detection, with potential applications in flexible touchless interactive panels.

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“…Lu et al 5 reported electron transfer from rGO to low-concentration NO 2 , while Hu et al 6 suggested electron transfer from NH 3 to rGO. Sensing of water vapor with rGO has been reported in various articles 7,8,9 , and it has been proposed that the interaction between rGO and water occurs through various mechanisms: 1) electron exchange, 2) proton transport via ionic conductivity and 3) an interlayer swelling effect 10 . The latter mechanism has been reported to cause hysteresis and compromise sensor sensitivity to humidity 11,12 .…”

mentioning

confidence: 99%

“…This was followed by a thermal reduction process under forming gas (H 2 /N 2 :5/95). More details on the process parameters are presented elsewhere 9 . The devices were exposed to high RH (>85%) for at least 450 seconds using a cool mist ultrasonic air humidifier (Capriccio T-253).…”

mentioning

confidence: 99%

Permanent water swelling effect in low temperature thermally reduced graphene oxide

Papamatthaiou

Argyropoulos

Masurkar

et al. 2017

Applied Physics Letters

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We demonstrate permanent water trapping in reduced graphene oxide (rGO) after high relative humidity (RH) exposure. For this purpose, we grew graphene oxide films via spin-coating on glass substrates followed by thermal reduction. The electrical resistance of the planar device was then measured. We observed that resistance is significantly increased after water vapor exposure and remains stable even after 250 days in ambient conditions. Various techniques were applied to desorb the water and decrease (recover) the material's resistance, but it was achieved only with low temperature thermal annealing (180 0 C) under forming gas (H 2 /N 2 mixture). The permanent effect of water absorption was also detected by x-ray photoelectron spectroscopy. Reduced graphene oxide (rGO) has attracted a strong research interest for gas sensing applications in recent years due to its unique electrical and chemical characteristics 1,2,3. Its main advantages among others are good chemical stability over time and ease of functionalization contributing to satisfying selectivity between various analytes 4. The gas sensing mechanism _____________________________

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The Effect of Thermal Reduction and Film Thickness on fast Response Transparent Graphene Oxide Humidity Sensors

Cited by 15 publications

References 2 publications

Ultrafast and Highly Sensitive Chemically Functionalized Graphene Oxide-Based Humidity Sensors: Harnessing Device Performances via the Supramolecular Approach

Ultrafast and Highly Sensitive Chemically Functionalized Graphene Oxide-Based Humidity Sensors: Harnessing Device Performances via the Supramolecular Approach

Ultrafast humidity sensor based on liquid phase exfoliated graphene

Permanent water swelling effect in low temperature thermally reduced graphene oxide

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