A highly sensitive double-layer structured nanodevice for moisture induced power generation

Abstract

With the increasing global energy demand, traditional energy sources are gradually failing to meet society’s needs while also having a potential of being harmful to the environment. As such, energy generating technologies capable of converting ubiquitous environmental energy into usable forms, such as electricity, have received increasing attention. In this research, a power generating device composed of a graphene (G) and titanium dioxide nanowire (TiO2 NWs) double-layer structure is prepared by an electrophoretic deposition method. Since both materials have special nanochannel structures and non-zero zeta potential, they can convert environmental energy into electricity through the diffusion, ionization, and natural evaporation of water. Furthermore, the efficiency of this novel sensor is much higher than their respective single-layer devices. By application of only 6 μl of water, the open circuit voltage (UOC) generated on the G-TiO2 sensor is as high as 1.067 ± (0.008) V. In comparison, TiO2 NWs single layer can only generate a UOC around 500 mV, and graphene itself can only produce a UOC no more than 250 mV under the same condition. Additionally, the effect of different deposition times of graphene on the surface morphology and thickness of graphene film is explored, and the effects of these changes in microstructure on performance is discussed in depth. Aside from power generation, the high sensitivity of the device to different volumes of water brings its use in the detection of trace amounts of water, and its high efficiency of energy conversion suggests a potential application as a power supply. This research not only provides a satisfactory candidate for inexpensive and efficient evaporative power generation, but also builds a foundation for developing new, intelligent, and self-powered electronic technologies.