On the nature of space charge and dipolar relaxations in Kapton film

Bhardwaj, Ruchi; Quamara, J. K.; Sharma, B. L.; Nagpaul, K. K.

doi:10.1088/0022-3727/17/5/015

Cited by 14 publications

(4 citation statements)

References 6 publications

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“…The charge fluctuations are probably related to charge traps in the substrate. [32,33] To estimate the sensitivity limit of the devices, i.e. the minimum signal at the gate that can be detected, we calculate the RMS gate noise U RM S using (U RM S ) 2 = f 2 f 1 S I gm 2 df , [34] with f 1 =4 Hz and f 2 =3 kHz, which is the relevant frequency range for biological signals.…”

Section: Resultsmentioning

confidence: 99%

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Flexible graphene transistors for recording cell action potentials

Blaschke¹,

Lottner²,

Drieschner³

et al. 2016

2D Mater.

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Graphene solution-gated field-effect transistors (SGFETs) are a promising platform for the recording of cell action potentials due to the intrinsic high signal amplification of graphene transistors. In addition, graphene technology fulfills important key requirements for for in-vivo applications, such as biocompability, mechanical flexibility, as well as ease of high density integration. In this paper we demonstrate the fabrication of flexible arrays of graphene SGFETs on polyimide, a biocompatible polymeric substrate. We investigate the transistor's transconductance and intrinsic electronic noise which are key parameters for the device sensitivity, confirming that the obtained values are comparable to those of rigid graphene SGFETs. Furthermore, we show that the devices do not degrade during repeated bending and the transconductance, governed by the electronic properties of graphene, is unaffected by bending. After cell culture, we demonstrate the recording of cell action potentials from cardiomyocyte-like cells with a high signal-to-noise ratio that is higher or comparable to competing state of the art technologies. Our results highlight the great capabilities of flexible graphene SGFETs in bioelectronics, providing a solid foundation for in-vivo experiments and, eventually, for graphene-based neuroprosthetics.

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Section: Resultsmentioning

confidence: 99%

“…Thus, we conclude that the noise is mainly dominated by charge fluctuations close to the active area of the graphene transistor whereas access regions play a minor role. The charge fluctuations are probably related to charge traps in the substrate [32,33]. To estimate the sensitivity limit of the devices, i.e.…”

Section: Resultsmentioning

confidence: 99%

Flexible graphene transistors for recording cell action potentials

Blaschke¹,

Lottner²,

Drieschner³

et al. 2016

2D Mater.

View full text Add to dashboard Cite

show abstract

“…The space charge can change the internal electric field, thereby influencing the orientation of the polar groups in PIA, as mentioned in equation ( 7); Moreover, the unsaturated carbonyl groups in the polyimide main chains can act as both trapping centers and dipoles, and the charge released from traps is associated with the onset of dipolar motion. The partial overlap of the bipolar discharge peaks (which means the overlap of activation energy value) also predicted the inseparable physical mechanism of space charge and dipole polarization [31].…”

Section: The Nature Of Dipole Orientation In Pia and Its Influence On...mentioning

confidence: 79%

“…On the one hand, polarization time and polarization temperature can affect the relaxation characteristics in PIA electret: The diploe polarization peaks appeared only when PIA exposed to temperatures above 120 • C and became more pronounced with the elevating temperatures, as shown in figures 4(a) and (d) (there were two inconspicuous negative discharge peaks at 60 • C and 140 • C in the TSD spectrum of the sample charged at 120 • C); And for both samples exposed at 120 • C, the annealed sample exhibited a much prominent negative peak, as showed in figure 4(b). The relationship of dipole relaxation and temperature in PIA electret can be described by the Arrhenius equation ( 8) [31]:…”

Section: The Nature Of Dipole Orientation In Pia and Its Influence On...mentioning

confidence: 99%

Charge transport characteristic and charge stability enhancement mechanism of polyimide aerogel as an ultralight weight electret

Song¹,

Ren²,

Hu³

et al. 2022

J. Phys. D: Appl. Phys.

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In this study, polyimide aerogel is applied as an ultralight-weight and thermally stable electret material, meanwhile its charge transport characteristic and charge stability enhancement mechanism are investigated. It is found that polyimide aerogel can exhibit excellent electret properties at 120℃ after corona charging at room temperature, and its charge stability acquires further promotion after charging at elevated temperatures or heat treatment, which far exceeds conventional polyimide-based electrets. Further research indicates that the outstanding charge retention characteristics of polyimide aerogel originate from the enhanced local defect density, fast retrapping effect, weakened internal electric field by dipole polarization, and prolonged conduction path, which are inextricably linked to its porous structure. In addition, the high gas breakdown strength in the pores of polyimide aerogel effectively limits the breakdown induced conductivity, thereby ensuring high space charge density and large piezoelectric response of polyimide aerogel electrets. Considering the extremely low density and inherently excellent properties of polyimide substances, polyimide aerogel may have promising prospects as an electret in the lightweight sensing and energy conversion devices at elevated temperatures.

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Thermally stimulated depolarization currents in poly(vinyl alcohol) films

1992

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Poly(viny1 alcohol) films were polarized at different electrical field strengths and temperatures. The peak temperature of the TSDC spectra shifted to higher values with increasing polarizing field strength and polarizing temperature. The activation energies and relaxation parameters of the process were evaluated. Based on the results, the origin of TSDC was attributed to space charge polarization with some contribution of dipole orientation. Thermisch stirnulierte Depolarisationsstrome in Poly(vinylalkoho1)-FilmenPoly(vinylalkohol)-Filme wurden bei unterschiedlichen elektrischen Feldstarken und Temperaturen polarisiert. Die Peaktemperatur der TSDC-Spektren verschob sich mit steigender Polungsfeldstarke und Polungstemperatur zu hoheren Werten. Die Aktivierungsenergien und die Relaxationsparameter des Prozesses wurden ermittelt. Auf Grund der Ergebnisse wurde der Ursprung der TSDC der Raumladungspolarisation mit einem geringen von der Dipolorientierung herriihrenden Beitrag zugeordnet. Acta Polymer., 43, 68-71 (1992) Thermally stimulated depolarization currents in poly(viny1 alcohol) films

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On the nature of space charge and dipolar relaxations in Kapton film

Cited by 14 publications

References 6 publications

Flexible graphene transistors for recording cell action potentials

Flexible graphene transistors for recording cell action potentials

Charge transport characteristic and charge stability enhancement mechanism of polyimide aerogel as an ultralight weight electret

Thermally stimulated depolarization currents in poly(vinyl alcohol) films

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