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Designing stretchable and skin-conformal self-powered sensors for intelligent sensing and posture recognition is challenging. Here, based on a multi-force mixing and vulcanization process, as well as synergistically piezoelectricity of BaTiO3 and polyacrylonitrile, an all-in-one, stretchable, and self-powered elastomer-based piezo-pressure sensor (ASPS) with high sensitivity is reported. The ASPS presents excellent sensitivity (0.93 V/104 Pa of voltage and 4.92 nA/104 Pa of current at a pressure of 10–200 kPa) and high durability (over 10,000 cycles). Moreover, the ASPS exhibits a wide measurement range, good linearity, rapid response time, and stable frequency response. All components were fabricated using silicone, affording satisfactory skin-conformality for sensing postures. Through cooperation with a homemade circuit and artificial intelligence algorithm, an information processing strategy was proposed to realize intelligent sensing and recognition. The home-made circuit achieves the acquisition and wireless transmission of ASPS signals (transmission distance up to 50 m), and the algorithm realizes the classification and identification of ASPS signals (accuracy up to 99.5%). This study proposes not only a novel fabrication method for developing self-powered sensors, but also a new information processing strategy for intelligent sensing and recognition, which offers significant application potential in human—machine interaction, physiological analysis, and medical research. [ABSTRACT FROM AUTHOR]

Minuscule pressure/stress detection with high sensitivity can recognize and deal with potential hazards timely, which is crucial for guaranteeing the security of human and stability of social functioning. Lithium niobate (LiNbO 3) single crystal possessing excellent piezoelectric and ferroelectric properties is suitable for fabricating piezoelectric pressure sensors. Therefore, in this paper, the pressure sensors based on LiNbO 3 single crystals with parallel connected structure were researched. Sensors with parallel connected structure can improve the sensitivity from 4.86 V/N of single sheet structure to 8.71 V/N under the stress between 0.01 N and 0.2 N at 30 °C. Both types of the sensors can detect the minuscule stress low to 0.01 N and minuscule pressure generated by balloon pump, blowing largely or slowly. The influence of temperature on sensors was also researched, and the results exhibited that sensors performed well from 30 °C to 60 °C and still sustained high sensitivity of 5.26 V/N of parallel connected structure and 3.71 V/N of single sheet structure at 60 °C. Besides, the response time of sensors to the pressure of balloon pump is 60 ms under different temperature. These excellent properties indicate the great potential applications of fabricated sensors in practical minuscule pressure/stress detection. [ABSTRACT FROM AUTHOR]

Highly skin-conformal wearable tactile sensors with high sensitivity and wide measurement range are promising for physiological signal monitoring, personalized recognition and human-machine interaction. In this paper, we report a hybrid piezoelectric-triboelectric sensor (HPTS) primarily composed of polarized micro-frustum-arrays structure lead-zirconate-titanate and polydimethylsiloxane (PZT&PDMS) composite film (m-PZT&PDMS) and m-Cu film, which can simultaneously generate the coupling of piezoelectric effect and triboelectrification by the contact-separation working mode. Combining the hybrid effect, micro-frustum-arrays structure and high piezoelectric constant material, the HPTS presents excellent sensitivity and wide measurement range. The HPTS can reach a sensitivity of 15.43 V/kPa when triboelectric effect performs in the pressure of 0 kPa–100 kPa, and 18.96 V/kPa when both the piezoelectric and triboelectric effects work in the pressure range of 100 kPa–800 kPa. In addition, the HPTS is largely based on the PZT&PDMS film being directly in contact with the skin, showing excellent skin-conformal characteristic. It also demonstrates good linearity, fast response time and high stability. These characteristics are attractive for sensing radial artery wave, monitoring the slide and touch of a finger, and detecting the strong pressure of limb movement. Hence, this work provides a new strategy by applying a highly skin-conformal piezoelectric-enhanced triboelectric nanogenerator with high sensitivity and wide measurement range as a wearable tactile sensor, exhibiting immense potential in medical research, personalized recognition and human-machine interaction. Based on the contact-separation working mode, the highly skin-conformal piezoelectric-enhanced triboelectric nanogenerator was fabricated with excellent sensitivity (18.96 V/kPa) and wide measurement range (0 kPa–1300 kPa), which presents immense potential in medical research, personalized recognition and human-machine interaction. Image 1 • Due to the use of m-PZT&PDMS film as the main body, the HPTS is able to provide more conformal and comfortable contact with irregular human skin and withstand complex deformations. • The developed hybrid nanogenerator has high flexibility, excellent sensitivity and wide measurement range. • The polarized m-PZT&PDMS film exhibits excellent output performance because the high piezoelectric modulus of PZT nanofibers, high weight ratio of PZT to PDMS and the optimized polarization parameters. • The highly-conformal HPTS shows the high sensitivity (18.96 V/kPa) and wide measurement range (0 kPa–1,300 kPa) to reliably and simultaneously detect weak and strong external forces in real-time, such as pulse waves and body movements. [ABSTRACT FROM AUTHOR]