Whether water-repellent or UV (UV) resistant, the surfaces have been treated to protect the glass panels and facades from costly and time-consuming cleaning.
Solar panels get dirty. Dust, sand and other materials accumulate on their surface, preventing the sun's energy from reaching the solar cell and causing a massive loss of efficiency of the photovoltaic system. But what to do when cleaning solar modules is not only very expensive but also labor intensive?
Researchers on the NewSkin project have found a way to solve this problem by developing hydrophobic, or water-repellent, surfaces that become superhydrophilic when exposed to UV light.
Unlike hydrophobic surfaces, in which water repels and contracts to form droplets, superhydrophilic surfaces have a very strong affinity for water to diffuse through it, maximizing contact with the material. This can help remove dirt from glass panels and facades more cheaply, reduce maintenance costs, and save more time while increasing solar energy production.
"We focus here on photo-induced hydrophilicity of surfaces," said PhD student Valentin Heiser of the NewSkin Fraunhofer Institute for Organic Electronics project partner, Electron Beam and Plasma Technology FEP (Fraunhofer FEP), Germany, in a press release. press published on the Institute's website. .
“To enhance this effect, for the first time we applied crystalline titanium oxide to ultrathin glass in the reel winding process. It's very effective. Super thin and light glass can be applied to the facade or applied directly. incorporated into solar panels as a composite material and even on curved surfaces."
Without UV radiation, titanium dioxide (TiO 2 ) is hydrophobic and forms water droplets. However, after exposing the TiO 2 coated surface to UV light for about 30 minutes, the Fraunhofer FEP researchers noticed that the surface changed from hydrophobic to superhydrophilic.
As a result, little or no dirt accumulates on the TiO 2 coated surface. The press release goes on to explain: “If, for example, traffic dust, sand or other debris accumulates on glass facades or solar panels, it will be removed by raindrops due to the hydrophobicity of the surface during the night. In addition, the cyclic alternation of hydrophobicity and superhydrophilic properties ensures that dirt does not adhere to surfaces during the day."
The researchers have now developed the first layer. They coated rolls of thin glass 30 cm wide and 20 m long (100 micrometers thick) with 30 to 150 nanometers of titanium oxide in a roll-to-roll system at the Fraunhofer FEP technical center. However, there are still challenges to overcome. Thin glass is a new substrate that is very fragile and very sensitive to thermal and mechanical stress.
In addition, TiO 2 achieves hydrophobicity and hydrophilicity only when it is in the form of crystals, which requires high temperatures during its production. The press release adds: “Until recently, spray coatings with these requirements could not be used in roll technology because conventional media such as foil could not withstand high temperatures. Thin glass offers an alternative here.
The research work carried out as part of NewSkin (Innovation Eco-system to Accelerate the Industrial Uptake of Advanced Surface Nano-Technologies) enabled scientists at Fraunhofer FEP to work on the optimal and cost-effective combination of TiO2 and thin properties. glass. bringing innovative products to market. Researchers from partner university Uppsala in Sweden are also working to transfer their results to polymer membranes.
Further information: NewSkin project website
Excerpt : Solving the Dirty Solar Panel Problem (14 February 2023) Retrieved 20 February 2023, from https://techxplore.com/news/2023-02-solar-panels-dirty-problem.html
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