Performance transition in droplet-based electricity generator with optimized top electrode arrangements

Harvesting electrical energy from water droplet is a sustainable and promising way to meet challenges in energy scarcity. The water kinetic energy has been successfully harvested into electricity energy by droplet-based electricity generator (DEG). By virtue of its novel transistor-like design with a top electrode, the DEG achieves a high instantaneous power density basing on bulk effect instead of interfacial effect. Despite this, how top electrode arrangement influences the electricity generation as a basic question is still obscure. Here, we study the impact of top electrode arrangement on the output performance of DEG. A transition between open system and closed system is found in the generator when the top electrode arrangement changes at vertical and horizontal direction. Such transition is further analyzed from the working mechanism, droplet dynamic behavior and output performance. Finally, an optimal top electrode arrangement is acquired, which will provide guidance in DEG design. We envision that such optimal top electrode arrangement of DEG will open new pathway for efficiently harvesting water droplet kinetic energy.