The utilization of spontaneous capillary driven water evaporation to generate electricity can be considered as a green and potential approach to the energy and pollution issues in very recent years. Various attempts have been made to harvest this green energy in the previous works, which is from the interactions between water molecules and solid materials of nano-structures. However, few literatures reported the capillary driven evaporation phenomena for the device design, especially the effect of geometry was not considered. Therefore, four porous carbon black films with different geometries are inhouse fabricated and tested in present work. It is found that the generated open-circuit voltages in different geometrical films are different accordingly. Through optimizing the geometry of the film, the generated voltage is increased by up to 200% in present experiment. It should be a promising way to improve the output performance of this kind of electricity generation devices. The principle behind this evaporation-induced electricity generation and the effect of geometry on volume flow inside the porous film are then revealed. The findings in this work can be used to guide the design of green evaporation-induced electricity generators.
Keywords voltage generation, capillary driven evaporation, geometry effect, nano porous films