Graphene oxide as high-performance dielectric materials for capacitive pressure sensors

Wan, Songming; Bi, Hengchang; Zhou, Yilong; Xie, Xiaoguang; Shi, Shaobo; Yin, Kuibo; Sun, Litao

doi:10.1016/j.carbon.2016.12.023

Cited by 216 publications

(129 citation statements)

References 56 publications

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“…On the other hand, considering the volume fraction for Milli-Q water, equal to V f ∼0.0361 at a weight fraction of 6.5 wt%, we find a value of 2.3 for the dielectric constant of the GO particles in Milli-Q water. Even if the two values found in Milli-Q water and IPA are just estimates of the dielectric constant of the particle, they are still significantly lower than the giant permittivity found in many other papers [7][8][9][10][11][12][13][14][15]30].…”

Section: Resultsmentioning

confidence: 61%

“…As stated by the authors, these giant dielectric constants would arise from the orientational polarization of oxygen-containing groups at the surface of GO planes and along the edges [10,11]. Very large permittivities have also been reported for GO based foams and sensors in absence of humidity [11][12][13][14]. According to the authors, the capacitive behavior of GO paper for sensing shows a strong dependence on temperature and relative humidity.…”

Section: Introductionmentioning

confidence: 88%

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Absence of giant dielectric permittivity in graphene oxide materials

et al. 2019

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Graphene oxide (GO) is considered as a promising component for electronics because of its unique anisotropy, easy processing and sometimes claimed giant permittivity. The latter would arise from an enhanced electronic polarizability due to the presence of functional groups at the surface and edge of GO flakes. As a matter of fact, a number of publications have reported a very large permittivity of GO materials. Nevertheless, the reported values for the intrinsic relative permittivity vary significantly from a few units to several millions. Such variability raises a critical question on the actual and intrinsic permittivity of GO, and on difficulties of measurements due to the polarization of the electrodes. We presently report impedance spectroscopy characterizations of GO solutions with different solvents. We find very large capacitance at low frequencies, in agreement with previous reports. However, we also show that these results can be interpreted without considering a giant permittivity of GO. Actually, a simple equivalent circuit model allows us to confirm that GO does not have a giant permittivity. We conclude that GO can be used as an electrolyte for supercapacitors, or as a precursor for electrically conductive graphene-based materials, but not as an efficient additive to raise the permittivity of solvents or composites for electronics and energy storage applications.

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Section: Resultsmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 88%

Absence of giant dielectric permittivity in graphene oxide materials

et al. 2019

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“…Only one capacitance‐type sponge sensor provided the higher initial sensitivity (0.8 kPa −1 ) . However, the operating stress range was limited within 4 kPa only . Generally, the sponge sensor with a higher sensitivity (0.8 or 0.18 kPa −1 ) had limited operating stress range (0–4 or 0–6.5 kPa), and the sensor with a greater operating range (0–10 kPa) had a smaller sensitivity (0.15 or 0.036 kPa −1 ) .…”

Section: Resultsmentioning

confidence: 99%

Silver Nanoflower Decorated Graphene Oxide Sponges for Highly Sensitive Variable Stiffness Stress Sensors

Khan

Ajmal

Bae

et al. 2018

Small

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Soft conductive materials should enable large deformation while keeping high electrical conductivity and elasticity. The graphene oxide (GO)-based sponge is a potential candidate to endow large deformation. However, it typically exhibits low conductivity and elasticity. Here, the highly conductive and elastic sponge composed of GO, flower-shaped silver nanoparticles (AgNFs), and polyimide (GO-AgNF-PI sponge) are demonstrated. The average pore size and porosity are 114 µm and 94.7%, respectively. Ag NFs have thin petals (8-20 nm) protruding out of the surface of a spherical bud (300-350 nm) significantly enhancing the specific surface area (2.83 m g ). The electrical conductivity (0.306 S m at 0% strain) of the GO-AgNF-PI sponge is increased by more than an order of magnitude with the addition of Ag NFs. A nearly perfect elasticity is obtained over a wide compressive strain range (0-90%). The strain-dependent, nonlinear variation of Young's modulus of the sponge provides a unique opportunity as a variable stiffness stress sensor that operates over a wide stress range (0-10 kPa) with a high maximum sensitivity (0.572 kPa ). It allows grasping of a soft rose and a hard bottle, with the minimal object deformation, when attached on the finger of a robot gripper.

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“…A 1000‐fold times resistance change can be realized within a pressure range of 1–70 kPa. Totally, the fabricated multimeter‐like pressure sensor shows a wide pressure range from <1 Pa to 72 kPa with different ultrahigh sensitivities using different sensing parts (15.22 kPa −1 for 0–300 Pa, 0.22 kPa −1 for 0.09–30 kPa, and 46.67 kPa −1 for 48–72 kPa), which present the prominent advantages in both the sensitivity and pressure range than some previous reports (Table S1, Supporting Information) …”

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confidence: 99%

Ab Initio Design of Graphene Block Enables Ultrasensitivity, Multimeter‐Like Range Switchable Pressure Sensor

Zang

Wang

Xia

et al. 2019

Adv Materials Technologies

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From the weighing instruments in ancient China to the modern high-precision electronic balances and further the in vivo pressure measurements, the pressure determination by using the pressure sensors is absolutely needed in our life. At present, there are many kinds of pressure sensors based on different mechanisms including resistance change, piezoelectricity, capacitance, potential, and other detectable physical quantities as output signals, [1][2][3][4] using multiform pressure sensing materials such as conductive polymers, nanowires, carbon nanotubes, graphene, and so on. [5][6][7][8][9][10][11][12] Particularly the resistance-type pressure sensor, which is based on the correlation between the resistance change and mechanical deformation, has attracted more attention in recent years due to its wide potential applications including soft robotics, wearable devices, touch-on flexible displays, and health monitoring systems. [13][14][15][16] Conventional resistance-type pressure sensors have been widely accepted with rapid development; however, despite the tremendous efforts devoted to the improvement of sensitivity and detection limit, the wide-range detection of pressure still remains as an open issue. As one of the next-generation pressure-sensing materials, graphene has been extensively explored owing to its mechanical flexibility and low detection limit. Nevertheless, it is now suffering from the same issues. [17,18] Typically, a pressure sensor based on a suspended single-layer graphene has been demonstrated to possess a wide pressure sensing range up to 100 kPa but with a low sensitivity (2.66 × 10 −5 kPa −1 ). [19] To build the high-performance sensors with better sensitivity and lower detection limit, vesiculation of the sensing materials has been recognized as a promising solution due to its advantages of high porosity, good flexibility, and excellent robustness under the mechanical strain/stress, especially in the graphene-based system. [20] So far, the controlled reassembly, hydrothermal reduction, freeze drying, and chemical vapor deposition (CVD) growth and other in situ foaming methods have been used to synthesize the graphene foams (GFs) and their congeners (sponges and aerogels) by utilizing the surface activity of the graphene or the graphene oxide (GO) nanofilm. [21][22][23][24][25][26][27] Representatively, Ren and co-workers improved In pursuit of the next-generation pressure sensors, the fabrication of graphene-based devices is considered to be one of the most promising approaches to address the unsatisfied sensitivity within a wide pressure range. Here, an ab initio design based on the graphene block is proposed to realize a high-performance and multimeter-like range switchable pressure sensor. The sensor contains three designed graphene-based foams with different initial resistances, which enable continuous resistance-change behavior induced by the pressure. Specifically, the reduced graphene oxide (rGO) foam-based sensor demonstrates a three times resistance change within the pressure ran...

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Graphene oxide as high-performance dielectric materials for capacitive pressure sensors

Cited by 216 publications

References 56 publications

Absence of giant dielectric permittivity in graphene oxide materials

Absence of giant dielectric permittivity in graphene oxide materials

Silver Nanoflower Decorated Graphene Oxide Sponges for Highly Sensitive Variable Stiffness Stress Sensors

Ab Initio Design of Graphene Block Enables Ultrasensitivity, Multimeter‐Like Range Switchable Pressure Sensor

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