(Invited) Tunable Elastomeric Optical Gratings Based on Triboelectric Nanogenerators

For people in life, the existence of triboelectrification usually is a kind of negative effect, especially in winter. However, the team of professor Zhong Lin Wang of Georgia Institute of Technology in the United states invented Triboelectric nanogenerator (TENG) to fully utilize this kind of effect. TENG can convert mechanical energy in the environment into electrical energy, which based on the principle of triboelectrification and charge induction, such as waves, sounds, muscle contractions, mechanical vibrations, etc. The charge separation between the two layers of polymer films will lead to the formation of potential difference. In addition, not only the fabrication process of TENG is simple and low cost, it also can be used in large-scale production. At the same time, it has excellent durability and plasticity, so TENG can be easily combined with other devices. Therefore, TENG and its applications are an important research direction of nanoenergy. Here we have designed TENG for different applications. Listed below is two applications in electrostatic manipulations based on TENG: 1. Integrate a TENG with electrostatic actuation system (EAS) to manipulate the movement of micro-droplets and fine solids. The mechanical triggering of the TENG produces a very high electrostatic field inside the electrostatic actuator, producing a Coulomb force that drives tiny objects (liquid or solid) in the electrostatic actuator. Therefore, the tribomotion of TENG can be used as a driving source and control signals of electrostatic actuators.2. Based on dielectric elastomer actuator (DEA), tunable optical gratings (TOGs) and TENG combined so that the grating period can be controlled by dielectric elastomer actuator. Therefore, a self-powered TOGs system can be implemented, with TENG as the power and control module for its system. In combination with unique output performance of the TENG, three different TOGs systems were designed and used to compress or expand the spacing of the grating array by driving the dielectric elastomer actuator.