Researchers in Türkiye have developed a passive dirt-resistant coating for PV panels using oleic acid-modified aluminum oxide nanoparticles applied via a spray coating. Laboratory and field tests showed that the coating reduced dust build-up and initially increased daily energy production, although performance declined under long-term environmental stress.
A research team from Konya Technical University in Türkiye has unveiled a passive anti-pollution solution for solar panels. The approach is based on a thin film of aluminum oxide (Al₂O₃) nanoparticles, modified with oleic acid, which is applied directly to the glass surface of photovoltaic modules using a simple spray coating technique.
“The coated surfaces were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) analyses, and their anti-fouling performance was evaluated under both laboratory and real environmental conditions,” the research team said. “This work aims to improve sustainable and efficient energy production, especially in arid areas where pollution is a significant challenge.”
The team started by synthesizing their anti-pollution solutions using aluminum isopropoxide, nitric acid, acetylacetone, oleic acid, hexane, toluene and isopropyl alcohol. Oleic acid concentrations of 0.5%, 1.5%, and 4.5% were tested, with each solution spray-coated onto glass substrates. Three spray durations were assessed for each concentration: 20, 40, and 80 seconds.
Characterization showed that the optimal coating was achieved with a spray time of 40 seconds and 1.5% oleic acid, yielding a film thickness of 231 nm and a water contact angle of 75.47°, indicating significantly improved surface properties. In comparison, uncoated glass samples showed an average water contact angle of 38.04°.
After optimizing the coating, the researchers applied it to mini solar modules in a laboratory environment. The modules were provided with layers of glass/ethylene vinyl acetate (EVA)/solar cell/EVA/Tedlar polyester (TPT) tailored to the wettability. The tests were carried out in a 1 m³ room with a module tilt of 32.08° and an irradiance of 1,000 W/m² provided by a halogen lamp. Environmental conditions ranged from 25–40 °C, relative humidity from 40–80%, wind speeds from 7.3–27.7 km/h, and dust loading between 0.5–5 g.
To validate performance under real-world conditions, the team installed three optimally coated mini-modules next to two uncoated reference modules on the campus of Konya Technical University. The modules, each containing a single 8 cm x 16 cm PV cell laminated with a 10 cm x 18 cm glass cover, were monitored daily between 7 a.m. and 6 p.m. from July 15 to August 12.
“Laboratory experiments have shown that the coated surfaces accumulate on average 6.9 mg/cm² less dust compared to uncoated surfaces, which translates into a reduction in energy efficiency losses of 0.6% to 3.0%,” the researchers said.
Field tests conducted under real environmental conditions indicated that the coated panels initially achieved higher daily energy yields and generated 0.5–0.8 W more power per day than the uncoated modules during certain periods. However, the researchers reported that the performance of the coated panels began to decline in early August, which they attributed to environmental stressors such as high temperatures, low wind speeds and the presence of hydrophobic pollutants in the air.
The new anti-pollution technology was presented in “A novel anti-pollution approach based on oleic acid-modified Al₂O₃ nanocoatings for photovoltaic panels”, published in Scientific reports. Researchers from Turkey’s Selçuk University participated in the study.
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