Cleaning glass facades and photovoltaic installations is costly and time consuming. Contamination reduces the yield of solar modules. There are good reasons to investigate surfaces that minimize this effort. Within the European Union-funded NewSkin project (GA: 862100), Fraunhofer FEP has successfully applied crystalline titanium oxide to ultra-thin glass using a roll-to-roll process, and under UV light We achieved a hydrophobic surface that becomes superhydrophilic.
The first results of this showcase of several of NewSkin’s open access upscaling facilities will be presented at the joint Fraunhofer booth (No. C2-528) at BAU 2023 in Munich, Germany from April 17th to 22nd. will be
In 2021, photovoltaics will cover 8.9% of Germany’s total electricity consumption1, generating 50 TWh. Of course, this should and must be increased for a sustainable energy transition. The dirt-repellent, easy-to-clean surface ensures transparency and cleanliness of the façade, ensuring more efficient and consistent energy production for solar and reducing maintenance costs.
“Here, we focus on the photo-induced hydrophilicity of the surface,” he said. The ultra-thin, lightweight glass can later be applied to facades, incorporated directly into solar modules as composites, or even into curved surfaces.”
Titanium dioxide changes its hydrophilicity. Water repellency when exposed to UV light (i.e. sun activation, etc.). Non-irradiated, hydrophobic. It forms water droplets. After irradiation it is super hydrophilic. Moisturizes perfectly. In the case of photoinduced hydrophilicity, the surface changes from hydrophobic to superhydrophilic. Irradiate with UV rays like the sun for 30 minutes.
Due to this effect, no or very little dirt adheres to surfaces with such a titanium dioxide coating. For example, if traffic dust, sand, or other contaminants land on a glass facade or solar panel, it will be washed away via beaded raindrops due to the surface’s hydrophobicity at night. In addition, the alternating hydrophobic and superhydrophilic properties keep dirt from sticking to the surface during the day.
UV-activated titanium oxide also decomposes surface organic molecules through photocatalysis. This produces antimicrobial and sterile surfaces that are of particular interest in relation to medical technology and flexible displays.
Researchers at Fraunhofer FEP have now developed the first coating. Specifically, a 30-cm-wide, 20-m-long roll of thin glass (with a glass thickness of 100 micrometers) was roll-coated with 30–150 nanometers of titanium oxide. to-roll system. This pilot plant for roll-to-roll coating of thin glass (FOSA LabX 330 Glass from VON ARDENNE) is located at Fraunhofer FEP.
One of the challenges of this showcase project is that thin glass is a very new substrate that breaks very easily and is sensitive to thermal and mechanical stresses and therefore has significant handling requirements. Second, titanium dioxide achieves its special properties of hydrophobicity and hydrophilicity only if it is crystalline. For this reason, high temperatures are required during manufacturing. Sputter coating with these requirements could not previously be implemented by roll-to-roll techniques because common substrates such as films could not withstand high temperatures. This is where thin glass offers an alternative.
Thanks to this initiative by NewSkin, Fraunhofer FEP scientists are now able to combine the properties of titanium dioxide and thin glass in an optimal and cost-effective way to bring innovative products to market with the industry. is working on The first successful coating on ultra-thin glass paved the way. Researchers at Nu Skin’s partner, Uppsala University, are also working to translate the results into polymer his films.
In the future, Fraunhofer FEP will also work on layer systems that can be activated not only with UV light but also with visible light. For example, nanoparticle fabrication and embedding, or nitrogen doping are also being explored.
Original: Hydrophilic coatings from rolls – easily retrofit facades and solar panels with ultra-thin glass
Than: Fraunhofer Association
