Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stab...Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.展开更多
In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors wer...In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors were fabricated by deposited PAN based LB thin films on the interdigitated electrodes.The gas-sensitivity to NO_2 of PAN based gas sensors with different layers was studied.It is found that pure polyaniline LB films present higher sensitivity,responsivity and reversibility to NO_2 gas compared with polyaniline and acetic acid mixed LB films.The response time of 3-layer and 15-layer pure polyaniline LB films to 20μg/g NO_2 gas is about 10 s and 30 s,respectively.The recovery time of the 15-layer pure polyaniline LB films is close to 5 min.展开更多
Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. T...Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. The photocurrent for the device with 5 μm interdigital spacing is five orders of magnitude higher than the dark current, and the room temperature detectivity is on the order of 2.4 × 1012cm Hz1∕2W-1at 5 V bias. Furthermore,the spectral response of this device possesses strong dependence on the polarization of incident light showing potential plasmonic effects with only microscale dimensions. These experimental data were analyzed using optical simulation to confirm the response of the devices.展开更多
We discuss the efficiency of an electro-optic (EO) polymer sensor with interdigitated coplanar electrodes. The developed EO sensor is used to detect terahertz radiation via EO sampling. Results show that the sensor ...We discuss the efficiency of an electro-optic (EO) polymer sensor with interdigitated coplanar electrodes. The developed EO sensor is used to detect terahertz radiation via EO sampling. Results show that the sensor improves more significantly detection sensitivity than does a sensor with sandwich configurations.展开更多
The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditio...The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditions.In this paper,a ferroelectric model,drawn from the typical interdigital electrode structure of a ferroelectric sensor,is established based on phase field theory,to study the polarization evolution and explore the evolution laws in ferroelectrics.Numerical results show that there appears ferroelectric creep even under an applied electric field below the coercive field value.Also,the configurational force theory is introduced to investigate the mechanical behaviors related to polarization switching in the ferroelectric samples with interdigital electrodes.It is found that configurational force and polarization have similar evolution laws in both time evolving and space distribution.And considering the configurational force as the driving force,it is possible to predict the potential direction of polarization evolution and explore its evolution mechanism in ferroelectrics,demonstrating the configurational force as a useful parameter for describing mechanical behavior during the polarization evolution and a powerful tool for investigating the evolution mechanism of microstructure with coupling effects in ferroelectric materials.展开更多
基金supported in part by the National Natural Science Foundation of China(Grant No.62104056)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ21F010010)+4 种基金the National Natural Science Foundation of China(Grant Nos.62141409 and 62204204)the National Key R&D Program of China(Grant No.2022ZD0208602)the Zhejiang Provincial Key Research&Development Fund(Grant Nos.2019C04003 and 2021C01041)the Shanghai Sailing Program(Grant No.21YF1451000)the Key Research and Development Program of Shaanxi(Grant No.2022GY-001).
文摘Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.
文摘In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors were fabricated by deposited PAN based LB thin films on the interdigitated electrodes.The gas-sensitivity to NO_2 of PAN based gas sensors with different layers was studied.It is found that pure polyaniline LB films present higher sensitivity,responsivity and reversibility to NO_2 gas compared with polyaniline and acetic acid mixed LB films.The response time of 3-layer and 15-layer pure polyaniline LB films to 20μg/g NO_2 gas is about 10 s and 30 s,respectively.The recovery time of the 15-layer pure polyaniline LB films is close to 5 min.
基金supported by the Air Force Office of Scientific Research (Grant No. FA9550-10-1-0136)NASA (Grant No. 242026-1BBX11AQ36A)+1 种基金supported by a University of Arkansas Honors College Undergraduate Research grantthe Microelectronics–Photonics program at the University of Arkansas for the COMSOL license
文摘Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. The photocurrent for the device with 5 μm interdigital spacing is five orders of magnitude higher than the dark current, and the room temperature detectivity is on the order of 2.4 × 1012cm Hz1∕2W-1at 5 V bias. Furthermore,the spectral response of this device possesses strong dependence on the polarization of incident light showing potential plasmonic effects with only microscale dimensions. These experimental data were analyzed using optical simulation to confirm the response of the devices.
基金supported by the National Natural Science Foundation of China(Nos.60871073 and 61201075)China Postdoctoral Science Foundation(No.2012M511507)
文摘We discuss the efficiency of an electro-optic (EO) polymer sensor with interdigitated coplanar electrodes. The developed EO sensor is used to detect terahertz radiation via EO sampling. Results show that the sensor improves more significantly detection sensitivity than does a sensor with sandwich configurations.
基金supported by the National Key R&D Program of China(2021YFA1201200)the National Natural Science Foundation of China(51973188,21774109,and 52203194)+3 种基金the Natural Science Foundation of Zhejiang Province(LR18E030002)the Zhejiang University Education Foundation Global Partnership Fundthe National Postdoctoral Program for Innovative Talent(BX20190297)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2019BT02X105)。
基金The authors are grateful for the support provided by the National Natural Science Foundation of China(Grant No.11772245).
文摘The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditions.In this paper,a ferroelectric model,drawn from the typical interdigital electrode structure of a ferroelectric sensor,is established based on phase field theory,to study the polarization evolution and explore the evolution laws in ferroelectrics.Numerical results show that there appears ferroelectric creep even under an applied electric field below the coercive field value.Also,the configurational force theory is introduced to investigate the mechanical behaviors related to polarization switching in the ferroelectric samples with interdigital electrodes.It is found that configurational force and polarization have similar evolution laws in both time evolving and space distribution.And considering the configurational force as the driving force,it is possible to predict the potential direction of polarization evolution and explore its evolution mechanism in ferroelectrics,demonstrating the configurational force as a useful parameter for describing mechanical behavior during the polarization evolution and a powerful tool for investigating the evolution mechanism of microstructure with coupling effects in ferroelectric materials.