Multifunctional high-performance pressure/proximity/temperature sensors enabled by hybrid resistive-supercapacitive response

The issue of sensitivity attenuation in high-pressure region has been a persistent concern for pressure-sensitive electronic skins.In order to tackle such trade-off between sensitivity and linear range,herein,a hybrid piezoresistive-supercapacitive(HRSC)strategy is proposed via introducing a piezoresistive porous aerogel layer between the charge collecting electrodes and iontronic films of the pressure sensors.Surprisingly,the HRSC-induced impedance regulation and supercapacitive behavior contribute to significant mitigation in sensitivity attenuation,achieving high sensitivity across wide linear range(44.58 kPa^(−1)from 0 to 3 kPa and 23.6 kPa^(−1)from 3 to 12 kPa).The HRSC pressure sensor exhibits a low detection limit of 1 Pa,fast responsiveness(~130 ms),and excellent cycling stability,allowing to detect tiny pressure of air flow,finger bending,and human respiration.Meanwhile,the HRSC sensor exhibits exceptional perception capabilities for proximity and temperature,broadening its application scenarios in prosthetic perception and electronic skin.The proposed HRSC strategy may boost the ongoing research on structural design of high-performance and multimodal electronic sensors.

Fiber-optic Fabry-Prot strain sensor based on graded-index multimode fiber

By using a graded-index multimode fiber （GI-MMF） with a relatively flat index profile and high refractive index of the fiber core, a microextrinsic fiber-optic Fabry Prot interferometric （MEFPI） strain sensor is fabricated through chemical etching and fusion splicing. Higher reflectance of the microcavity is obtained due to the less-curved inner wall in the center of the fiber core after etching and higher index contrast between the GI-MMF core and air. The maximum reflection of the sensor is enhanced 12 dB than that obtained by etching of the Er- or B-doped fibers. High fringe contrast of 22 dB is obtained. The strain and temperature responses of the MEFPI sensors are investigated in this experiment. Good linearity and high sensitivity are achieved, with wavelength-strain and wavelength-temperature sensitivities of 7.82 pm/με and 5.01 pm/°C, respectively.

Multimodal probe for optical coherence tomography epidetection and micron-scale indentation

We present a multimodal ferrule-top sensor designed to perform the integrated epidetection of Optical Coberence Tomognphy(OCT)depth-profiles and micron-scale indentation by all-optical detection.By scarning a sample under the probe,we can obtain structural crosse soction images and identify a region of interest in a nonhomogencous sample.Then,with the same probe and setup,we can immediately target that area with a series of spherical indentation measurements,in which the applied load is known with aμN precision,the indentation depth with sub-/m precision and a maximum contact radius of 100 pm.Thanks to the visualization of the internal structure of the sample,we can gain a better insi ght into the observed mechanical behavior.The ability to impart a small,confined load,and perfomn OCT A scans at the same time,could lead to an altemative,high transverse resolution,Optical Coherence Elastography(OCE)sensor.