Nanotechnology is the manipulation of matter on an atomic, molecular, and supramolecular scale. When something is small enough in the quantum-realm scale and shows the quantum mechanical effects, we will say it's "nano". The small here we said is in the nanometer scale, which is one over a billion of a meter. Usually, nanomaterials will have an excellent and amazing feature which does not exist in the same but bulk scale material.

Chlorophyll of plants is a typical natural photocatalyst. The difference between chlorophyll to man-made nano photocatalyst is, usually chlorophyll captures sunlight to turn water and carbon dioxide into oxygen and glucose work as photosynthesis, on the contrary man-made photocatalyst creates strong oxidation agent and electronic holes to breakdown the organic matter to carbon dioxide and water in the presence of photocatalyst, light and water, which usually is decomposing process.

Our nano photocatalyst technology acts to keep the surface for self-cleaning in three stages, using three distinct properties: anti-static, photocatalysis and hydrophilicity. First of all, the coated porous surface has the anti-static feature which can make less dust absorbed on it. Then in sunlight, photocatalysis causes the coating to break down organic dirt adsorbed onto the window chemically. When the glass is wet by rain or other water, hydrophilicity reduces contact angles to very low values, causing the water to form a thin layer rather than droplets, and this layer washes dirt away.