Self‐Powered Optical Switch Based on Triboelectrification‐Triggered Liquid Crystal Alignment for Wireless Sensing

Abstract

Here, a self-powered optical switch (OS) composed of a surface-etched single-electrode triboelectric nanogenerator (TENG) and a polymer-dispersed liquid crystal (PDLC) film is reported. The working principle of the developed OS is that the liquid crystal alignment can be driven by triboelectrificationgenerated voltage, inducing the PDLC film to rapidly switch its initial translucent state to an instantaneous transparent state. An output voltage of 360 V is generated upon the PDLC film when a nitrile rubber film contacts with the TENG at an area of 25 cm 2 and a velocity of 0.4 m s −1 . As such, a wide dimming range with the relative transmitted light intensity from 0.05 to 0.85 can be achieved for the OS. Enabled by the unique mechano-electro-optical reaction, the effects of a series of structural parameters on the performance of the OS are methodically studied. Particularly, through integrating the OS with a visible-light-operated signal-processing circuit, a complete wireless sensing system with a fully power-free sensing node is developed. The paradigms of hand touching and foot stepping triggered wireless alarms are demonstrated, explicitly showing great potential for the system in many possible interactive human-machine interface applications, such as surveillance, security systems, remote operation, and automatic control.

Progress inTENGtechnology—A journey from energy harvesting to nanoenergy and nanosystem

“…102 As to the sustainable wearable HMIs, human-machine interaction is reported regarding in cyberspace or controlling of advanced robots in 2017. 103 Meanwhile, the TENG technology also has augmented a wide range of optical functions including light emission, photodetection, and optical modulation for the realization of applications including self-powered luminescence, smart display, wireless communication, personal privacy protection, motion monitoring, the self-powered optical wireless transmission (in 2019), 104 and even further nanophotonic modulation by integrating TENG with AlN nanophotonics (in 2020). 105 As a promising technique for energy harvesting from the ambient environment, TENG has shown great advantages as a power supply for IoT in simple structure and with unique advantages (high efficiency, high energy density, cost-effectiveness, and good reliability).…”

“…Besides polymer dispersed liquid crystal, self-powered elastomer-based tunable displays are also realized by TENG. 104,256 The voltage output from TENG induces rippling of the elastomer that varies its transparency. Recently, TENG has been successfully applied for nanophotonic modulation.…”

Adaptive optical beam steering and tuning system based on electrowetting driven fluidic rotor

“…In contrast to beam steering by light refraction, the beam steering by tuning the reflecting membrane orientation via EWOD can significantly mitigate the dispersion and aberration of optical signals during transmission, leading to an insertion loss as low as~1.5 dB. (2) Innovative rotary electrodes are designed for EWOD actuation and hence hub rotation with a large beam steering range. The annulus-shaped EWOD electrodes enables the reflecting membrane fulfill a full loop of rotation without the limitation of contact angle saturation 23 .…”

“…D uring the past two decades, the development of multifunctional sensing networks, swift signal transmission systems, and advanced wireless communication techniques has grown rapidly. Their applications are ubiquitous in our daily lives, ranging from optical switches [1][2][3] , laser beam security networks 4 , in-home WiFi antenna networks 5 , global positioning systems (GPS) 6 to autonomous vehicle remote control 7 . To make these advanced sensing and telecommunication networks feasible in a more complex environment, a higher level of beam signal transmission standards, e.g., avoidance of signal mitigation over a longer transmission distance and alleviation of the multi-path fading phenomenon, needs to be carefully addressed.…”

Self-powered user-interactive electronic skin for programmable touch operation platform

“…On the basis of the fact that humans cannot directly obtain information in electrical signals, the process of giving feedback to human in HMI relies on the human-perceivable signals such as visible light, sound, and force (10)(11)(12)(13). Visible light is generally considered as the best candidate because of its higher spatial resolution and intuitiveness, such as using a display screen (14,15). However, with the rapid development of wearable devices, artificial prosthetics, and robotics, the traditional interactive medium is difficult to meet the needs in terms of flexibility, portability, and low power consumption (16)(17)(18)(19)(20).…”