Self-cleaning glass: electric fields remove particles from window surfaces

A research team from China's Zhejiang University has developed a self-cleaning glass based on alternating electric fields that can remove dust particles from the glass surface, among other things. According to the scientists, this method is in principle suitable for all glass surfaces, including car windscreens, greenhouses and the glass surfaces of solar cells. Production is said to be inexpensive on an industrial scale.

Cleaning windows and glass surfaces in general, such as solar cells, requires a great deal of effort. Regular cleaning of large glass surfaces on buildings is expensive.

The Chinese researchers' self-cleaning method is said to be comparatively simple, as the scientists write in the study "Coverable Self-Cleaning Glass via Abnormal Transport and Jump of Charged Particles", which was published in Advanced Science. The approach is better than existing self-cleaning methods, which do not work well enough under dry, dusty conditions or require constant maintenance.

Cleaning effect through alternating electric fields

The researchers found that dirt particles on glass surfaces exposed to alternating electric fields can loosen and jump off. This applies to both organic and inorganic particles. However, the effectiveness of the electric fields depends on the field strength and the particle size.

The scientists therefore investigated how these factors influence the movement of the particles. From this, they developed a design for a transparent glass that is only 0.62 mm thick and can clean itself within a few seconds. Around 98 percent of organic and inorganic particles can be removed without the use of water, cleaning agents or chemical substances. The energy required to generate the electric fields is low. In addition, the system does not require any maintenance, meaning that the overall costs are lower than with conventional cleaning.

The electric fields also have another effect: when switched on, they ensure that charged particles in the air are deflected and cannot settle on the surface. According to the scientists, up to 90 percent less dust can settle on a glass surface. This means that the glass surfaces of solar cells in solar parks in dusty desert areas, for example, can also be effectively protected from contamination.

The glass itself is transparent and only influences the incidence of light in the infrared range. The transmission of visible light is only marginally affected.

Manufacturing the glass on an industrial scale is inexpensive because only conventional materials and techniques are used. Electrodes are etched into the glass pane and covered with a thin protective film.

(olb)