All-printed soft triboelectric nanogenerator for energy harvesting and tactile sensing. (December 2020) - Li, Hui
Abstract: Rapid advancements in flexible and multifunctional electronics bring challenges to the corresponding power suppliers. Soft triboelectric nanogenerator (TENG), as a promising route to satisfy the demands of various self-powered sources and energy harvesting devices, has been developed in this study via facile all-printing method. The nanogenerator features a thin film with micro patterned friction silicone layers, which is fabricated through direct ink writing technology. Wrinkled silver electrode is sandwiched and protected by silicone layers, and constructed through prestrain, release, and buckling process based on inkjet printing technology. As an experimental result, TENG with 100% prestrain produces the maximum output voltage of 44.16 V at the frequency of 5 Hz and external force of 10 N, higher than the pristine nanogenerator. The output voltage of these TENGs could be enhanced slightly when it is stretched to a certain degree. The as-prepared TENG can work for biomechanical energy harvesting driven by human motions and instantaneously power 20 commercial Light Emitting Diodes (LEDs). Moreover, the all-printed soft TENG arrays show potential applications in tactile sensor for touch perception. Our work opens a new idea for fabrication of flexible and wearable TENG based on printing technology to shorten fabrication cycle, simplify individual design and make it more accessible for practical application. Graphical abstract: In this work, we present an all-printed soft triboelectric nanogenerator that is designed to harvest small mechanical energy. Based on the direct ink writing technology, the friction layer can be fabricated with regular micro structures to enlarge the surface area, and to protect the sandwiched electrode inside as well. The wrinkled silver electrode is constructed on the prestretched friction layer according to the inkjet printing process. The assembled TENG with an activation area of 10 × 10 mm 2, operating in the contact-separation mode, can achieve an output voltage of 44.16 V at the prestrain 100% with the applied force of 10 N and frequency of 5 Hz. A power density of 1.03 W/m 2 could be produced correspondingly to drive 10 commercial LEDs connected in series. In addition, TENG can also be applied to monitor the movements of waist, foot and elbow for biomechanical energy harvesting, and the printed arrays have the potential application in mapping the touch location as tactile sensor. This simple, low-cost, controllable and reliable approach to TENG device based on all-printing technology provides new dimensions for rapid manufacturing of energy harvesters and wearable self-powered sensors. Image 1 Highlights: Flexible and stretchable triboelectric nanogenerator was proposed based on all-printing method. Micropatterned friction surface was constructed via direct ink writing. Wrinkled silver electrode was fabricated through inkjet printing. The powerful TENG is a promising candidate for portable and wearable biosensors.