If we examine the structure of a typical photovoltaic module on section, we will realize that the different layers have their own optical properties and affect the incoming light each one in a different way.
The way light interacts with a panel depends on the wavelength and angle of incidence. We can generally distinguish the following basic cases of light transmission in a solar panel:1. The sun’s rays are reflected without transmission.
2. The rays are spread at the air-glass surface and absorbed via the glass.
3. The rays are reflected at the glass-pocket meeting point and then are either reflected back to the interior, or spread out in the air.
4. Perfect condition: The rays are absorbed completely by the solar cells.
5. The rays are reflected in the sac- solar cell meeting point.
6. The rays are absorbed by the rear module or reflected by it.
The importance of light transmission through the protective glass without any obstacles to the optimum function of the module is obvious. Above all, case 1 must be prevented, in which the light does not spread at all in the glass. Solarskin™, on the one hand enhances the anti-reflective properties of the panel, because of the uniform micro-asperity profile that it develops in it and on the other hand helps the unobstructed light transmission through the glass, because its surface is kept clean more easily. The final result is to keep the PV module running at peak performance and its long-term preservation.
Solarskin™ protects the glass and prevents pollutants from entering the substrate, because it creates an invisible barrier of thickness at most 100 nm over the surface. This means that any force that causes scratching or abrasion may remove pollutants easier.
When this force is rainwater (or the cleaning’s crew), then all the inorganic pollutants are directly removed, since the water only dissipates inorganic pollutants and not organic.
The inorganic pollutants (oxides and other types of inorganic pollutants) represent the majority of the pollutants. Rain however, apart from the dissolving capacity water has, performs mechanical tension. Therefore, the stronger the rain, the better is the cleaning of the module after the application of Solarskin™. The gradient assists this effect even more, since water entrains with mechanical tension the pollutants away from the surface. Besides the inorganic, the mechanical impulse of the rain entrains the organic pollutants too, which normally requires special cleaners. In case of drought, washing with tap water, even without any cleaner, the owner can clean the modules easily knowing that they would definitely be cleaned at 100% of any inorganic pollutants and 95% of organic pollutants. Similarly, the cleaning crew will do the job even sooner and with even better results. Without Solarskin™, however, it is totally impossible to achieve such a high cleaning result.
In the surface’s chemistry, before the chemical reaction of a substance with the substrate takes place, there are two phases: first the physical adsorption (which develops weak attractive forces) and secondly, the chemical sorption (the strong form of adhesion). Imagine that a pollutant is adsorbed, like all pollutants, at first naturally and not chemically, on the surface of a module. With Solarskin™ even wind is sufficient to remove it. If the pollutant remains for some time on the module (from a few seconds until several hours) the second stage will inevitably follow, which is the chemical sorption. This occurs only when Solarskin™ has not been applied; thus, depending on the conditions and the type of the pollutant, cleaning would be even more difficult, so that perfect cleaning results can NEVER be achieved. With Solarskin™ though, chemical sorption is completely prevented and the pollutants either drop from the inclined surface and fall to the ground due to gravity, or remain temporarily upon the surface, until a blow of strong wind, or until it rains, or until the cleaning crew comes and easily remove them with plain water. In other words,it is a simple natural phenomenon.