Luminescent pigments – very exciting!

The physicochemical explanation of photoluminescence can be very intricate, but to get an idea of how it works one can say that it involves electrons which are very excited to meet photons.

When a photoluminescent object is subjected to light -it will glow. This works due to that electrons of the object absorb the energy of the light, or rather of the photons. This excites the electrons and the electrons “jump” up. When the electrons are “jumping” down again the object will reemit light, but at a different wavelength. This causes a change of colour.

So, what is the difference between phosphorescence and fluorescence? An easy way to distinguish between phosphorescence and fluorescence is the ability to afterglow. For fluorescence, the afterglow is basically non-existent whereas phosphorescent objects can glow for several hours after they have been illuminated. So, how does this work? Both phenomena work as mentioned before by giving electrons a boost of energy. For phosphorescent objects, these materials are able to store this energy for a longer time. Therefore, they can have an afterglow for several hours. For fluorescent objects these are only glowing while being illuminated. One can make the comparison between a safety sign for emergency exits which might be visible through the night compared to bank notes under UV-light.

W&F offer several luminescent pigments. Our portfolio includes both fluorescent and phosphorescent pigments. Fluorescent pigments are mainly used for security applications. The pigments with afterglow can be found in safety-passage ways and exit guidance systems in public buildings, hospitals, factories, stations and tunnels, as well as on trains, airplanes and ships. These are also safe to use in toys.

Now wasn’t this exciting?!