Reporters recently learned from the City University of Hong Kong, led by the university’s academic research team, successfully developed a new drop-type generator. The drip generator is equipped with a transistor-like structure, which increases its instantaneous power density by thousands of times compared to similar droplet generators and greatly improves the efficiency of electrical energy conversion. The results were published in the latest issue of the journal Nature.
It is understood that the traditional droplet generator based on the friction and electrostatic induction of the droplet impact surface to generate electricity, but by the surface friction charge limit, this way of power conversion efficiency is low. Two key findings by the research team overcome this problem.
The team member, Professor Wang Jingkai of the City University of Hong Kong, said the two key findings were that the surface static charge generated by the continuous impact of water droplets on the long-term charge-free electro-material, PTFE, would continue to accumulate to saturation levels. The second is that they have developed a unique structure similar to field-effect transistors consisting of an aluminum electrode and a tin oxide (ITO) electrode with a surface with a ptFE film. When the droplets hit the surface of the PTFE/ITO and dispersed on the surface, because the water is conductive, it “connects” the path between the aluminum electrode and the PTFE/ITO electrode, turning it into a full circuit that can be energized. Based on this design, continuous water droplets cause a high density surface static charge to accumulate on the PTFE. At the same time, whenever the water droplets are connected to the two electrodes, all the charges on the accumulation of PTFE are released, generating an electric current. As a result, both instantaneous power density and power conversion efficiency are significantly increased.
“Our research shows that a drop of 100 microliters of water is dropped from a height of 15 cm, producing more than 140 volts, and the generator generates enough electricity to light up 100 small LED lights. Wang said the research could help develop more water resources around the world and could be promoted and installed on surfaces of different liquids and solids in the future, such as ship bodies, coastal shores and even umbrella surfaces, to take advantage of low-frequency hydrodynamic sofe.