Researchers from Spain's Materials Science Institute of Seville (CSIC-US) and the University of Seville recently developed a multifunctional fluorinated polymer (CFₓ) thin film deposited via plasma technology, enabling hybrid perovskite solar cells (PSCs) to harvest energy from both sunlight and raindrops while boosting environmental durability.
This room-temperature, solvent-free plasma process coats PSCs conformally up to 400 nm thick, delivering over 90% optical transparency that preserves champion power conversion efficiency (PCE) at 17.9%. The film's fluorine-rich groups (optimized to 36.4% CF₂ + CF₃ species) repel moisture, allowing cells to retain over 50% initial PCE after 10 days of high humidity-temperature stress and enabling compatibility with commercial UV-curable resins for 15-minute water immersion tolerance. As a triboelectric layer atop an FTO electrode, it converts raindrop kinetic energy via contact electrification and electrostatic induction in a drop-driven TENG (D-TENG) setup.
The integrated PSC/D-TENG maintains 80% performance after 300 hours of humid illumination and operates over 5 hours under 0.5 sun lighting with continuous dripping. Standalone optimized D-TENGs produce open-circuit voltage peaks of 110 V and ~4 mW/cm² power density per rainwater droplet, enduring over 17,000 impacts with 85% output retention; in hybrid mode, it yields 11.6 mA/cm² short-circuit current under 0.5 sun and 12 V peaks per drop. A proof-of-concept prototype, using a custom boost converter, powers LED arrays by charging a supercapacitor from combined solar and rain inputs, ideal for IoT sensors in smart cities or remote sites.
This innovation addresses PSC instability to moisture while synergizing photovoltaic and triboelectric mechanisms in a thin-film stack compatible with direct/inverse architectures, paving the way for robust "solar-rain" panels in variable weather. Funded by ERC's 3DScavenegrs and Next Generation EU's Drop Ener projects, it highlights plasma polymers as scalable encapsulants for multisource harvesters powering low-energy electronics.
