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With the arrival of the Internet of Things era, the demand for tactile sensors continues to grow. However, traditional sensors mostly require an external power supply to meet real-time monitoring, which brings many drawbacks such as short service life, environmental pollution, and difficulty in replacement, which greatly limits their practical applications. Therefore, the development of a passive self-power supply of tactile sensors has become a research hotspot in academia and the industry. In this review, the development of self-powered tactile sensors in the past several years is introduced and discussed. First, the sensing principle of self-powered tactile sensors is introduced. After that, the main performance parameters of the tactile sensors are briefly discussed. Finally, the potential application prospects of the tactile sensors are discussed in detail. [ABSTRACT FROM AUTHOR]

Flexible sensors are the essential foundations of pressure sensing, microcomputer sensing systems, and wearable devices. The flexible tactile sensor can sense stimuli by converting external forces into electrical signals. The electrical signals are transmitted to a computer processing system for analysis, realizing real-time health monitoring and human motion detection. According to the working mechanism, tactile sensors are mainly divided into four types—piezoresistive, capacitive, piezoelectric, and triboelectric tactile sensors. Conventional silicon-based tactile sensors are often inadequate for flexible electronics due to their limited mechanical flexibility. In comparison, polymeric nanocomposites are flexible and stretchable, which makes them excellent candidates for flexible and wearable tactile sensors. Among the promising polymers, conjugated polymers (CPs), due to their unique chemical structures and electronic properties that contribute to their high electrical and mechanical conductivity, show great potential for flexible sensors and wearable devices. In this paper, we first introduce the parameters of pressure sensors. Then, we describe the operating principles of resistive, capacitive, piezoelectric, and triboelectric sensors, and review the pressure sensors based on conjugated polymer nanocomposites that were reported in recent years. After that, we introduce the performance characteristics of flexible sensors, regarding their applications in healthcare, human motion monitoring, electronic skin, wearable devices, and artificial intelligence. In addition, we summarize and compare the performances of conjugated polymer nanocomposite-based pressure sensors that were reported in recent years. Finally, we summarize the challenges and future directions of conjugated polymer nanocomposite-based sensors. [ABSTRACT FROM AUTHOR]

Simplified fabrication technology and excellent sensing performance are highly desired for the development of flexible and user-friendly wearable sensors. However, there is usually a trade-off between the simplicity of the fabrication technology and the sensing performance of the device. Recently, paper-based wearable sensors have attracted much attention due to their excellent flexibility, simplified preparation, and low cost etc. However, the pressure sensitivity of the paper-derived sensors is far from satisfactory. In this work, a strategy of pencil graphite frottage (PGF) is reported by employing sandpaper as template and a pencil sketch technique to achieve functional printing paper as pressure-sensitive layers for electronic skin (e-skin). As a result, the e-skin prepared by our PGF technique shows excellent reproducibility and pressure sensing performance, including a maximum sensitivity of 7202.2 kPa−1, a fast response time of 25.0 ms, and an excellent durability over 20,000 loading/unloading cycles, and high ambient stability (> 6 months). For application demonstration, the e-skins are applied to monitor human wrist pulses, acoustical vibration and information encryption. Furthermore, pressure sensing arrays are developed and employed to map the spatial pressure distribution, indicating potential application in intelligent robots and prosthetics. It is believed that the fabrication strategies proposed in this work can bring insight onto the other area of bionic e-skin and multifunctional sensor devices. • Simplified fabrication technology and excellent sensing performance of paper-derived tactile sensors. • High performance tactile sensors achieving a high sensitivity of 7202.2 kPa−1. • E-Skin for health monitoring and information encryption. [ABSTRACT FROM AUTHOR]