Schottky MSM-Structured Tribovoltaic Nanogenerator Enabling Over 25,000 nC Charge Transfer via Single Droplet Impact

Using water droplets to generate electricity is an attractive approach for addressing the energy crisis. However, achieving high charge transfer and power output in such systems remains a major challenge. Here, a tribovoltaic nanogenerator (TVNG) is developed based on a specially designed Schottky metal-semiconductor-metal (MSM) structure. This device is capable of efficiently converting the kinetic energy of water droplets into electricity. To improve performance, a patterned interface layer between the metal and semiconductor is introduced, which helps guide charge flow and control surface conductivity. Upon droplet impact, the mechanical friction between the liquid and the surface generates a potential that activates charge transport across the Schottky barrier. This breaks the equilibrium state and enhances carrier movement. As a result, the device achieves a record-high charge output of 25500 nC from a single droplet, along with an output energy of 5.8 × 10⁻⁶ J. To showcase scalability, a TVNG module with 60 cells on a 3-inch wafer delivers milliamp-level current and charges a 220 µF capacitor to 0.6 V within 2 s. The effects of processing, materials, structure, and droplet properties are studied to guide the future design of high-efficiency Schottky MSM-based TVNG.