Effects of AC frequency on the capacitance measurement of hybrid response pressure sensors
Effects of AC frequency on the capacitance measurement of hybrid response pressure sensors
复制标题
交流频率对混合响应压力传感器电容测量的影响
DOI：
10.1039/d2sm01250b
复制
发表时间：
2022
期刊：
影响因子：
3.4
通讯作者：
Lu, Nanshu
中科院分区：
文献类型：
--
作者：
Li, Zhengjie;Ha, Kyoung-Ho;Wang, Zheliang;Kim, Sangjun;Davis, Ben;Lu, Ruojun;Sirohi, Jayant;Lu, Nanshu
由软压力传感器组成的电子皮肤正在为软机器人、生物集成设备和可变形触摸板提供技术支持。电容式压力传感器(CP)的一个众所周知的瓶颈是灵敏度随着压力的增加而急剧下降。为了克服这一挑战，我们发明了一种混合响应压力传感器(HRPS)，它同时显示了含有碳纳米管(CNT)掺杂的高孔纳米复合材料(PNC)固有的压阻和压电容效应。HRPS由两个导电电极构成，中间夹着一个叠层PNC和一个坚硬的介质层。我们将混合响应简化为一个并联的电阻-电容电路，其输出取决于用于电容测量的交流频率。在这里，通过理论分析，我们发现了一个控制HRPS频率响应的无量纲参数。通过对不同掺杂比例、不同压缩应变、不同交流频率下的HRPS的实验，验证了主曲线的正确性。此外，压阻机构和压阻机构的相对贡献也随着这三个参数的变化而变化。基于这一实验验证的理论，我们建立了一个非常实用的指导原则来选择最佳的交流频率来测量高功率因数合成器的电容。
E-skins consisting of soft pressure sensors are enabling technology for soft robots, bio-integrated devices, and deformable touch panels. A well-known bottleneck of capacitive pressure sensors (CPS) is the drastic decay in sensitivity with increasing pressure. To overcome this challenge, we have invented a hybrid-response pressure sensor (HRPS) that exhibits both the piezoresistive and piezocapacitive effects intrinsic to a highly porous nanocomposite (PNC) with carbon nanotube (CNT) dopants. The HRPS is constructed with two conductive electrodes sandwiching a laminated PNC and a stiff dielectric layer. We have simplified the hybrid response into a parallel resistor–capacitor circuit, whose output depends on the AC (alternating current) frequency used for the capacitance measurement. Herein, through theoretical analysis, we discover a dimensionless parameter that governs the frequency responses of the HRPS. The master curve is validated through experiments on the HRPS with various doping ratios, subject to different compressive strains, under diverse AC frequencies. In addition, the relative contribution of piezoresistive and piezocapacitive mechanisms are also found to vary with the three parameters. Based on this experimentally validated theory, we establish a very practical guideline for selecting the optimal AC frequency for the capacitance measurement of HRPSs.