Fully Flexible Single-electrode Triboelectric Nanogenerator With Micro-nano Structured PDMS

Energy crisis has been more evidence day by day due to energy shortage, whichlimits the world economic development and the human civilized progress. To solvethe problem on energy crisis, recycle energy has to be researched greatly. Some kindsof recycle energy have been applied in our life, such as solar, water, wind, biology andtide. Apart from those energies, there are abundant and random energies with smallenergy density around us, for instance the mechanical energy of human beings, therotational energy of moving cars. It has been an attractive research area on harvestingthose energies.Nanogenerator is a novel device which can harvest energy vibration and convertit into electric energy. There are three kinds of nanogenerators up to now. They arepiezoelectric nanogenerator, pyroelectric nanogenerator and triboelectricnanogenerator. The triboelectric nanogenerator has unique advantages compared withthe former two ones. It can be used to harvest various of energy and can be easilyintegrated into hybrid nanogenerators. The output voltage of triboelectricnanogenerator is larger and it is suitable for massive production due to the cheaperfabrication cost. The working mechanism is the combination of contact electrificationand electrostatic induction. Typical triboelectric nanogenerator is made of twomaterials with different triboelectric series and two electrodes covered on theiroutsides. However, in actual life, not all the friction layers can be covered byelectrode. This issue has been solved perfectly by single-electrode triboelectricnanogenerator. The charges generated by contact electrification drive electronsflowing between electrostatic electrode and ground, forming electric signals. Becausethe skin can be used as a friction surface, the single-electrode triboelectricnanogenerator extends the potential applications of nanogenerator significantly, suchas in touch technology. But the existing single-electrode triboelectric nanogeneratorsbased on the skin consist of polymer materials with micro-nano structures on the top side and electrode on the reserved side. Those micro-nano structures are made by Sitemplate transferring technique and the electrode is either Cu foil or ITO. Moremethods of making micro-nano structures that can be used in triboelectricnanogenerator and the fully flexible characteristic should be investigated for futurevarious and flexible electronic devices. In my work, a fully flexible single-electrodetriboelectric nanogenerators has been made based on micro-nano structured PDMSand silver nanowires.The nanogenerator here is made of PDMS and silver nanowires. On the top sideof PDMS, there are many irregular micro-nano structures which are fabricated byfemtosecond laser ablation, serving as a friction surface. On the bottom side of PDMS,there are overlapped silver nanowires embedded in PDMS which are made bytransferring technique, serving as induction electrode. The device can convertmechanical energy into electrical energy, driven by bared fingers directly withoutapplied voltage and medium. It is a fully flexible device since the fully flexibilities inPDMS and silver nanowires. It has been demonstrated that the micro-nano structuresmade by femtosecond laser is important in enhancing the energy conversionefficiency through comparing the output voltages. Besides, it works well after it isbent500times. And the working mechanism has been verified through a series oftests again. What’s more, as a actually application example, when it is attached onclothes by tape, the fully flexible single-electrode triboelectric nanogenerator stillworks successfully.