Self-powered Nanosystems Based On Nanogenerators

Because self-powered nanosystems could power themselves by harvesting energy from the environment and converting it into electrical energy, they can power the functional devices in the system without external power source. As a result, self-powered nanosystems are extremely useful in many fields such as military reconnaissance, environmental monitoring, intelligent traffic control and human health monitoring. Nanogenerator is one of the devices which could be used as the power source of a self-powered nanosystem as they can convert the wasted mechanical energy in the environment into electrical energy. In recent years, scientists fabricated some self-powered nanosystems with nanogenerators as the power source for the detection of ultraviolet(UV) light, biological molecules, chemical substance and so on. Furthermore, by storing the electrical energy in a capacitance or a cell, the signal could be transmitted wirelessly and displayed qualitatively. Even so, it is still a great problem to detecting self-poweredly and quantitatively in real time with these self-powered nanosystems, without using the detecting equipment which needs external power supply. In this thesis, we try to solve this problem by improving the performance of nanogenerators and decreasing the power consuming of the system.We successfully improved nanogenerators’ performance by orienting the nanowires in a piezoelectric nanogenerator or making oblique nanowires on the surface of a triboelectric nanogenerator or injecting charges into a triboelectric nanogenerator. Using these methods, the nanogenerators’ open circuit voltage and short circuit current were increased to 1.9, 2.0, 1.7 times and 1.6, 2.6, 2,1 times against before, respectively. In this way, a nanogenerator could generate more electrical energy and power functional devices which need more energy supply. Moreover, we fabricated a triboelectric nanogenerator sensitive to UV light as well as a biocompatible piezoelectric nanogenerator which could be driven wirelessly.After that, using a high performance triboelectric nanogenerator, we made a self-powered UV level detecting nanosystem which could show the level of UV light by the number of glowing LEDs; using the triboelectric nanogenerator sensitive to UV light, we fabricated a self-powered UV detecting nanosystem; using the wirelessly driven nanogenerator, we fabricated a self-powered biodetecting nanosystem, which could power an in-vivo biosensor and transmit the data wirelessly. All these nanosystems could work at real time withoutpower storage or any external power supply, thus providing a way for further study of self-powered nanosystems.