Researchers have built a hybrid device that generates electricity from both sunlight and falling raindrops by layering a triboelectric nanogenerator on top of a halide perovskite solar cell. The work, described in the journal Nano Energy, solves a persistent problem: perovskite cells degrade quickly when exposed to moisture, yet the new design uses that very moisture as a second energy source. With a patent already filed and potential smart-city applications in view, the device signals a practical step toward all-weather renewable power.
The prototype integrates a perovskite photovoltaic stack with a drop-driven triboelectric nanogenerator in a single, compact module. Instead of treating encapsulation as a purely protective add-on, the researchers turned the outer coating into an active component that harvests mechanical energy from rain. According to the peer‑reviewed device report, the combined output from light and droplets is modest at laboratory scale but demonstrates that a single surface can both shield a fragile absorber and serve as a triboelectric interface. That dual role is key to keeping the architecture thin and potentially compatible with building-integrated or lightweight urban installations.
How a Fluorinated Film Does Double Duty
The core innovation is a plasma-deposited fluorinated carbon film, referred to as CFx, that sits on top of the perovskite solar cell. This thin layer serves two roles at once. First, it acts as a moisture barrier, shielding the notoriously water-sensitive perovskite absorber from humidity. Second, it functions as the active triboelectric surface of a drop-driven nanogenerator that converts the mechanical energy of impacting water droplets into electrical current through contact electrification. By combining encapsulation and energy harvesting into a single material, the team avoids stacking separate protective and generating layers, keeping the device compact.
The triboelectric effect itself is straightforward: when a water droplet strikes the CFx surface and then rolls off, the charge transfer between the liquid and the fluorinated film produces a small voltage pulse. Thousands of these pulses, collected over time, add up to usable power. Meanwhile, sunlight passes through the semi-transparent upper structure and reaches the perovskite absorber below, generating steady photovoltaic current. A preprint on the device architecture details how the CFx coating, electrodes, and perovskite layers are arranged to minimize optical losses while still providing enough surface roughness and hydrophobicity for efficient droplet motion. The architecture means the device can produce energy during rain, during sunshine, and during the mixed conditions that are common in many climates but wasted by conventional solar panels.
Durability Numbers That Matter for Perovskites
Perovskite solar cells have long promised high efficiency at low manufacturing cost, but their sensitivity to water has kept them out of real-world deployment. The new hybrid addresses that weakness directly. After encapsulation with the CFx coating, the device maintained around 80% of its initial output after 300 hours of continuous illumination under humid conditions, while simultaneously enduring prolonged droplet exposure. That figure, while modest compared to the decades-long warranties on commercial silicon panels, represents a significant gain for a perovskite device operating in wet environments and suggests that the encapsulant is doing more than just delaying inevitable moisture ingress.
The mechanical resilience is equally telling. The same tests confirmed stable operation after more than 17,000 droplet impacts, suggesting the CFx surface does not degrade rapidly under repeated water contact. The methodology summary indicates that the team used controlled droplet sizes and fall heights to mimic moderate rainfall, enabling reproducible stress conditions. Together, these results indicate that the plasma-deposited coating can withstand the dual stresses of humidity and physical impact well enough to warrant further scaling research, though long-term outdoor field data remain absent from the published record. How the film will respond to UV-induced aging, airborne pollutants, and temperature cycling is still an open question.
Building on a Decade of Solar-Rain Hybrids
The idea of harvesting energy from both sun and rain is not new. A 2015 study in Nano Energy demonstrated an early self-cleaning hybrid module that paired a solar cell with a water-driven triboelectric generator and used superhydrophobic surfaces to keep the panel clean while generating power from droplets. That work established the design rationale for combining optical transparency, water repellence, and triboelectric activity in a single surface, but it relied on robust photovoltaic materials that did not face the same moisture challenges as perovskites.
By 2018, researchers had demonstrated a silicon-based hybrid in which the triboelectric nanogenerator shared an electrode with the underlying solar cell, reducing device complexity and improving electrical coupling. Follow-up efforts pushed toward system integration: one study reported a panel-scale array of triboelectric units laid over photovoltaic modules, while another explored surface texturing strategies that enhanced both droplet mobility and light trapping. Each iteration refined the engineering, but none tackled the specific problem of protecting a perovskite absorber from the very water the triboelectric layer needed to function. That gap is what the current CFx-based design fills, and it explains why the work has drawn attention despite the relatively early stage of testing.
Smart-City Ambitions and Open Questions
The researchers see near-term applications in low-power urban infrastructure. According to a university news release dated February 2026, the team stated that “its implementation in so-called smart cities is feasible, such as in signage, autonomous auxiliary lighting or monitoring.” The same statement notes that a patent has been filed for an “Energy Harvesting Device,” positioning the technology as a candidate for distributed power sources that can be laminated onto street furniture, transit shelters, or building façades where wiring and maintenance access are limited.
Those ambitions, however, rest on assumptions that the current data do not fully verify. No published cost analysis or scalability study accompanies the research, and the durability tests were conducted under controlled indoor conditions that cannot capture the full spectrum of outdoor stressors. Real-world deployment would subject the device to wind, dust, temperature swings, and variable rain chemistry, all of which could affect both the triboelectric output and the perovskite stability in ways that 300 hours of lab illumination cannot emulate. The absence of direct comparative testing against commercial silicon hybrids also leaves open whether the perovskite approach can match the reliability benchmarks set by earlier, more mature technologies, or whether its niche will be confined to applications where weight and form factor matter more than lifetime.
Why All-Weather Harvesting Changes the Value Equation
Even with those caveats, the hybrid’s basic proposition is compelling: instead of treating cloudy, rainy days as dead time for solar assets, the device turns precipitation into an auxiliary power source. In climates with frequent showers or monsoon seasons, the ability to recover some energy from rainfall could smooth out fluctuations in off-grid systems powering sensors, safety beacons, or small communication nodes. The CFx-based architecture is particularly suited to such roles because it leverages the same outer layer for protection and generation, potentially simplifying maintenance and replacement compared with multi-layer stacks that separate encapsulation from triboelectric functionality.
At a broader level, the work underscores a shift in how researchers think about renewable surfaces. Rather than designing single-function modules optimized for peak output under ideal conditions, engineers are increasingly exploring multi-modal interfaces that trade maximum efficiency for resilience and versatility. The CFx-perovskite hybrid is a clear example: its laboratory efficiency and lifetime lag behind mainstream silicon, but it offers a pathway to lightweight, conformable, and all-weather harvesters that could slot into the fabric of smart cities. Whether that promise translates into commercial products will depend on follow-up studies that extend testing into real outdoor environments, refine large-area deposition of CFx films, and quantify how much value intermittent rain-powered generation adds to urban energy systems over the long term.
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*This article was researched with the help of AI, with human editors creating the final content.
