A material is photo-active when it is activated by light. Activating means coming alive, which in scientific terms means being able to respond to a stimulus. Just as the heart produces electrical pulses that we can see on an ECG, titanium dioxide responds to light by generating radicals, which like electrical pulses can be recorded using a technique called electron paramagnetic resonance (EPR).
And it is precisely through these EPR analyses, conducted in the laboratories of the University of Turin, that for the first time we were able to record the activity of ACTIVE SURFACESTM when illuminated by a LED lamp, concretely demonstrating what happens to a photo-active material when the light comes on.
When pure titanium dioxide is illuminated by a simple visible light, like a LED lamp, the spectrum gives no signal. On the other hand, a constant and periodic signal is recorded when tiny silver nano-particles are deposited on the surface of the TiO2. Silver in fact absorbs the photons in visible light, bringing inert matter to life when a simple LED lamp is switched on.
When the light comes on, the periodic pulse recorded by the spectrum measures the formation of radicals. What does this mean? Radicals, just like the free radicals that form in the human body, are unstable species which, as such, want and need to react. But, while in our body they speed up cell ageing processes, and are therefore a disadvantage (not by chance we try to fight them in every way!), on our materials they trigger and speed up reactions that help to break down harmful substances, bacteria and viruses.
With the patented technology that exploits micrometric titanium dioxide decorated with silver nano-particles, ACTIVE SURFACESTM are activated, fighting pollution when the (natural or artificial) light is on, and now we are able to actually observe this process.