Flexible Alternating‐Current Electroluminescence Plunging to Below 1 Hz Frequency by Triboelectrification

Abstract

The basic structure of high-field EL is an alternating-current electroluminescent (ACEL) device, where the electrons in the phosphor or injected by the electrode are accelerated in the crystal and collide with the luminescent center to excite or ionize under the applied electric field, and emit radio light when electrons return to the ground state. [11,12] Compared to the traditional LED, the ACEL device has attracted widespread concerns due to its low power consumption, long service life, and excellent mechanical stability, however, the high frequency and unavoidable high driving voltage required for light-emitting limits the wide application in smart wearable field. Meanwhile, with the rapid development of science and technology, electronic devices have shown a trend of miniaturization, low power consumption, and multi-function, thus it is urgent to find a low carbon, environmentally friendly, and clean energy to get rid of the dependence on traditional power sources. Pioneered by Wang and co-workers, nanogenerators based on the coupling of the triboelectrification and electrostatic induction have been developed in the last few years, [13][14][15] ushering a new era of environmental energy collection and utilization. Unlike traditional chemical batteries, which have a limited lifespan and need to be replaced or recharged frequently. [16][17][18] The TENG have shown unprecedented output performance and advantages in harvest randomly distributed or irregular mechanical energy from the environment into electrical energy, Low frequency, portable power source is one of the key challenges for applications of wearable alternating-current electroluminescent (ACEL) device because it typically requiresa working frequency above 500 Hz. Here, an extremely low frequency self-powered ACEL system is proposed, which consists of a vertical contact-separation triboelectric nanogenerator and a self-made flexible ACEL device. It achieves directly-driven electroluminescence phenomenon in real-time by triboelectrification and works completely self-powered through converting kinetic energy of human body into electricity. The working frequency has fallen from 500 to 1 Hz, i.e., the real frequency needed for electroluminescence has dropped 500 times, which is due to the favorable low-frequency high-voltage advantages of the triboelectric nanogenerator. It delivers a stabilized open-circuit voltage of 160 V and a short-circuit current of 6 µA for applied force of 0.1 N. Meanwhile, a strong blueshift is also observed experimentally with the change of working frequency. Furthermore, a self-powered medical protective gown is demonstrated that is real-time monitoring both the temperature and humidity. This work breaking the bottleneck of high-frequency driving, demonstrates the great potential of self-powered ACEL systems in wearable electronics and medical health.

Active Deformable and Flexible Triboelectric Nanogenerator Based on Super-Light Clay

“…Figure d–f shows the output performance at different frequencies ranging from 0.5 to 2.5 Hz with a uniform contact area of 4 cm 2 . There is no significant change in the open-circuit voltage and the charge transfer amount, but the short-circuit current increases linearly with the increase of frequency, which means a faster contact-separation movement results in a higher current flow Figure g–i shows that the SLC can also generate different output intensities when rubbed with different materials.…”

“…There is no significant change in the open-circuit voltage and the charge transfer amount, but the short-circuit current increases linearly with the increase of frequency, which means a faster contact-separation movement results in a higher current flow. 33 Figure 3g−i shows that the SLC can also generate different output intensities when rubbed with different materials. Compared with these materials, the Kapton rubbed against the SLC has the best performance.…”

Double-Network Hydrogel for Stretchable Triboelectric Nanogenerator and Integrated Electroluminescent Skin with Self-Powered Rapid Visual Sensing

“…Copper-doped zinc sulfide (ZnS:Cu) in the phosphor layer has excellent chemical stability and electroluminescence properties. In particular, ZnS as the primary material while Cu as the luminescent element in the center emits green or blue light upon excitation [29][30][31][32][33]. Emission materials can be easily tuned using doping with different concentrations and types of elements; incorporating and co-doping with different transition metals is an important way to prepare inorganic luminescent materials.…”

Flexible alternating current electroluminescent devices integrated with high voltage triboelectric nanogenerators

“…44,45 Hence, the self-powered ACEL devices based on TENGs have tremendous potential in wearable devices and flexible displays, however little work has been conducted in this regard. [46][47][48] In this work, we firstly demonstrated a flexible TENG based on crumpled aluminum (Al) films with an easy fabrication process and high performance. Instead of using traditional complex lithographic techniques, it is easy and cost-effective to introduce a crumpled surface microstructure.…”